All IGCSE Physics Practicals 2015

IGCSE Physics Practical’s 2015

Practical 100

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Measuring -Part 1 and Part 2 Gear: PART 1 -blocks of various shapes and sizes, micrometer, calipers PART 2 -stopwatch, 60 glass slides, micrometer, calipers, electronic scales, string, meter ruler, pendulum Instructions Record your data in a suitable table Choose one of the blocks and sketch its shape (spend no more than 1 minute to do this) Label each length, width and height; l, w and h Measure each length with your ruler, caliper and micrometer Calculate the volume and surface area of the block. Show your calculations.

Formulae 2 a=l a=lw a = ½ bh 2 a = πr 3 v=l v = lwh 2 v = πr h

area of a square = length of side squared area of a rectangle = length x width area of a triangle = ½ x base x height area of a circle = π x radius squared volume of cube = length of side cubed volume of cuboid = length x width x height volume of cylinder = π x radius squared x height

PART 2 Instructions Use the appropriate instrument or method to measure the following and explain why; 1. 2. 3. 4. 5. 6. 7.

the length of your homework diary ........................... .............. . the width of your homework diary ........................... .............. . the thickness of your student ID card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . the radius of your pen ........................... .............. . length of string that has been wrapped 10 times around your pen . . . . . . . . . . . . . . . . . . . . . . . the thickness of a glass slide ........................... .............. . the period of oscillation for a 25cm length pendulum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Practical 102

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Number of Oscillations of a Simple Pendulum Gear: simple pendulum, retort stand, boss head, clamp, cork with slit, metre ruler, stopwatch Instructions 1. Set up the gear as shown – use a length of about 30 cm. 2. Record it. ______________________________________ 3. Hold the bob about 5cm from vertical. Start the timer when you release the bob at position ‘a’. 4. Stop the timer when it returns to the same point. This is one oscillation. Record this as t and n = 1. 5. Repeat for n =2 (the bob makes two oscillations) One oscillation occurs when the bob moves from a to b to c and back to a. 6. Repeat for other numbers of oscillations. 7. Complete a table as shown; N (number of oscillations) 1 2 3 5 8 11 14

t- time (s)

The length should be taken from the pivot point to the centre of mass of the bob

Plot a graph of t (vertical axis) against n (horizontal axis). Plot a cross ‘x’ at each point Draw a line of best fit (best guess) Use your graph to estimate the time for 10 oscillations

Practical 102

1. 2. 3. 4. 5.

NAME ______________________________________________________

How does the number of oscillations compare with the time taken? Is there a pattern? Is there a formula you could write to relate N and t? Can you use the formula to determine how many oscillations would occur if T = 20 s? Can you use the formula to determine T for 30 oscillations (if possible)?

Practical 104

NAME ______________________________________________________

Macleans College IGCSE Physics Practical

Oscillations of a Simple Pendulum Gear: simple pendulum, retort stand, boss head, clamp, cork with slit, metre ruler, stopwatch In this investigation you are to record the period of oscillation of a simple pendulum. One oscillation occurs when a pendulum bob moves from ‘a’ through b to c and then back to a. The time this takes is called a ‘period’

Instructions 1. Read through these instructions before you begin 1. Set up the gear shown. 2. Set the length of the pendulum to 0.40 m 3. Record 10 oscillations in your table. 4. Calculate T, the period of one oscillation. 5. Repeat for a length of 0.25m 6. Repeat the above using different lengths and record the data on a table as shown Length of pendulum (m) 0.25 0.40

Time for 10 oscillations (s)

Time for one oscillations(s)

Practical 104

NAME ______________________________________________________

7. Draw a graph of Time for one oscillations(s) vertical axis against Length 8. Plot the points accurately with a small ‘x’ for each point on the axes below 9. Draw a simple smooth curve to match the points. your curve does not need to touch any points but an accurate data would)

Time for one oscillations

Length (m) 10. Does your graph suggest that the time for an oscillation is proportional to the length? 11. What you did to make your results as accurate as possible

LO

Measure and describe how to measure a short interval of time Using graph skills

Practical 106

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Density Gear: metal cubes, glass slides, electronic balance, 100 mL measuring cylinder, small items (eg fishing sinkers or stainless steel nuts that fit into measuring cylinder), water, rags, beakers metal

density (kg m-3)

aluminium

2700

titanium

4500

zinc

7135

iron

7850

brass

8500

copper

8930

lead

11340

uranium

18900

gold

19320

tungsten

19600

Instructions Copy and complete the table

Object

1. 2. 3. 4. 5.

length/mm

width/mm

thickness/mm

mass/g

volume /cm-3

Measure the length, width and thickness of a glass slide. Weigh the mass of glass slide with electronic balance (in g) Calculate the density of the glass slide. Use 1000 kg m-3 = 1g cm-3 Determine the density of the metal cubes. Can you identify them? Explain how you would use a measuring cylinder to determine the density of an irregularly shaped object.

density /g cm-3

Practical 106

NAME ______________________________________________________

LO *Describe an experiment to determine the density of a liquid and of a regularly shaped solid and make the necessary calculation *Describe the determination of the density of an irregularly shaped solid by the method of displacement, and make the necessary calculation * use Density = mass / volume

Practical 200

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Describing motion Gear ticker timer, ticker tape, power supply Each student needs 4 x 25cm lengths of ticker tape Produce dots on the tape that show (i) steady speed (ii) higher steady speed (iii) increasing speed (iv) increasing then decreasing speed Glue these tapes into your books and label them. For each tape plot a distance-time graph for the first 20 dots (0.0s – 0.40s). Either; use a different colour for each tape or new graph paper

Extension Produce speed time graphs for your tapes

Practical 202

NAME ____________________________________________________

Macleans College IGCSE Physics Practical Calculating Average Speed Gear: trolley, ramp, metre ruler, stopwatch Aim To calculate average speed 1. Release a trolley from rest 2. Observe the motion.

trolley

3. Assume its speed at the end of the ramp is v final 4. Think of a way to determine its average speed v

ave

5. Write your method so that another y11 student can follow your instructions 6. Try it. 7. Write your results and explain how the average speed is related to the final speed.

Questions A trolley is released from rest at the top end of a 1.8 m track. It has a final speed of 3.6 m/s at the lower end of the track. Qu 1 What was its speed at 0.9 m from the top end of the track? Qu 2 What was the time of travel? Qu 3 What assumption has been made to answer the above questions?

Practical 204

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Distance along a ramp Gear: 1.2 m length ramp, block (10cm), trolley, stopwatch, 1m ruler Instructions

7. Set the gear as shown in the diagram 8. Place the trolley at the top of the ramp. Determine its position on the ramp. ___________ 9. Time the trolley to travel 0.2 m down the ramp. 10. Record in a table as shown Distance travelled / m 0.2 0.5 0.7 0.9 1.0 1.1

Time /s

Acceleration / m s-2

11. Repeat for increasing distances as indicated by the table above. 12. Calculate its acceleration using : a = 2 x distance travelled divided by time squared

7. Plot a graph of distance travelled (vertical axis) against time on these axes 8. Draw a single smooth curve 9. What conclusion can you make regarding the motion of a trolley down a gentle slope? 10. What would be the shape of the speed-time graph of this arrangement?

Practical 205

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Measuring Acceleration Gear: trolley, 1.2 ramp, ticker timer, 12 V a.c. supply, 1m ticker-tape, sticky tape, scissors Aim To analyse acceleration using a ticker timer. The ticker timer produces exactly 50 dots each second. Therefore the time to make two adjacent dots is 0.02 s. From the spacing of the dots, you can work out the acceleration of the trolley. The diagram shows a length of ticker-tape fixed to a trolley. As the trolley rolls down the ramp it pulls the ticker tape.

1 2 3 4

Set up the apparatus as in the diagram. Use 12V ac. Switch on the ticker timer and adjust the wing nut if the hammer does not work. Release the trolley (You may need to try different angles). Remove the tape and cut it into sections 10 dot-spaces long. Stick these side by side in your book/ page. The length of each section of tape shows the distance travelled by the trolley in 0.2 s (see diagram). Choose a ‘slow’ section of tape and measure its length. Work out the average speed of the trolley over that section using this equation: average speed (m/s)

5 6 7

length of section (m) =

time (s)

Choose a ‘fast’ section of tape. Use the above equation again to work out the average speed over this section. Work out the time between your slow’ and ‘fast’ sections. It is 0.2 seconds for every section. So this example shows 0.8 seconds. Calculate the acceleration of the trolley using this equation: acceleration (m/s2)

=

‘fast’ speed – ‘slow’ speed (m) time between sections (s)

Do either 8 or 9 8 Repeat with the ramp angle 2-5o steeper. 9 Describe and sketch a distance time graph if the acceleration was 1 m s-2

Practical 206

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Acceleration due to gravity Gear: ticker timer, 12 V a.c. supply, 0.60 m ticker-tape (for each student), sticky tape, 50 g mass Instructions 1. Set the gear as shown in the diagram (the ticker timer is about 0.5 m above the ground). ticker timer

tape

mass

2. Do a trial run to see if the tape runs smoothly through the ticker timer. 3. Only when the mass is at the highest position and the tape is not twisted and clear of the gaps then turn on the ticker timer. Then release the mass. 4. Repeat until each student has their own ticker tape to analyse i. ii. iii. iv.

Mark the first clearest dot and label it 0.0s Mark every 5th dot and label them 0.1s 0.2s 0.3s etc. (ignore rebounds or double marks) Measure the distance, between each mark (in metre) Calculate the average speed between marks using distance / 0.1 seconds Distance travelled between marks/ m

Time /s 0.0 0.1 0.2 0.3 0.4 0.5 0.6

Average speed/ m s-1

Practical 206

v. vi.

NAME ______________________________________________________

vii.

Plot average speed (vertical axis) against time (be neat, tidy, accurate) Draw a line of best fit (best estimate of a line that passes through maximum number of points with minimum spread) Determine its gradient (use rise over run and include units)

viii.

What does the gradient mean? What is its unit?

Practical 207

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Finding acceleration from a ticker tape Gear: trolley, 1.2 ramp, ticker timer, 12 V a.c. supply, 0.5 m ticker-tape, tape Aim To determine acceleration using a ticker timer. 1. 2. 3. 4. 5.

Mark the first clearest dot (start). Label it 0.0s Mark every 5th dot until end of the tape. Label each mark (0.1s, 0.2s…) Enter time in column 1

6. 7. 8.

Calculate the distance between each mark and enter into column 2. Calculate average speed between marks ( v = (d 2 -d 1 )/0.1 =) and enter into column 3 Calculate the acceleration ( a = (v 2 -v 1 )/0.1 )and enter into column 4

Time (s)

Distance between marks (m) Δd = d 2 – d 1 etc

0.0 0.1 0.2 0.3 0.4 0.5 0.6

Write a conclusion (based on your data)

Average speed between marks (m/s) ave v = Δd/ 0.1

Acceleration (m/s/s) a = (v 2 -v 1 )/0.1

Practical 207

EXAMPLE Time (s)

NAME ______________________________________________________

Distance between marks (m) Δd = d 2 – d 1 etc

Average speed between marks (m/s)

Acceleration (m/s/s) a = (v 2 -v 1 )/0.1

Ave v = Δd/ 0.1

0.0 0.1 0.2 0.3 0.4 0.5 0.6

0.009 0.022 0.031 0.043 0.053 0.067

0.09 0.22 0.31 0.43 0.53 0.67

1.3 0.9 1.2 1.0 1.3

In this example the acceleration fluctuates between 0.9 and 1.3 m/s/s ie approx. 1.1 m/s/s Calculate your acceleration (and uncertainty) from your data

Practical 208

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Measuring g (the acceleration due to gravity) Gear: steel ball bearing free fall adaptor and Pasco photo gate timer Instructions 1. Read through these instructions before you begin 2. Set up a retort and clamp on a table to hold the free fall adapter Release clamp

Height

Pasco photo gate timer

Pressure sensor pad

3. 4. 5. 6. 7. 8.

Practice dropping the ball bearing from the clamp so it hits the sensor pad every time When you are ready then turn on the timer (check it reads zero) Release the ball Record the time and the height Repeat and average Use your average time in the equation s = ut + ½ at2 u = initial speed = zero 9. Try three different heights 10. Make a conclusion

Practical 212 Practical 209

NAME ______________________________________________________

Macleans College IGCSE Physics Practical

Terminal velocity Gear: 2 x 1 meter rulers, stopwatch, A4 paper, paper clips, sticky tape Instructions 1. Read through these instructions before you begin 2. Construct a suitable table for all of your results 3. Measure 2.000 m height. 4. Drop a sheet of A4 paper from the height and record the time to reach the ground 5. Repeat this three times and average the results 6. Fold the paper in half and repeat the measurements 7. Fold again and repeat 8. Continue until you are no longer able to fold the paper (or upto 7 folds) 9. Repeat step 4 and 5 with a paper clip taped to the centre of the sheet 10. Repeat step 10 with the paper completely folded so it has very little surface 11. In each trial release the sheet parallel to the ground (where possible). 12. Write a conclusion for this experiment. Extension Either Design a sheet of A4 paper to maximize the time for the paperclip to reach the ground Explain how these images relate to this practical

1. 2. 3. 4. 5. 6. 7.

Read through these instructions before you begin Construct a suitable table for all of your results Tape a paper clip near the center of an A4 sheet Hold the sheet horizontally 2.000 m above the ground Drop it and time it to reach the floor Repeat this three times and average the results Fold the paper in half and repeat the measurements (leave the paper clip on the outside) 8. Continue until you are no longer able to fold the paper (or upto 7 folds) 9. Plot Size of paper horizontal axis vs time 10. Explain in terms of forces why this pattern occurs

A ball falls from a very high position from rest and reaches terminal velocity. 1. Describe its motion as it reaches terminal velocity 2. Explain how terminal velocity occurs in the ball.

Practical 212

Jumbled sentences SORT THESE SENTENCES INTO TWO PARAGRAPHS TO ANSWER THE QUESTIONS Some of the sentences are wrong and must be discarded 1) At terminal velocity friction is balanced by the weight of the object. 2) Initially the acceleration is 9.8m/s/s. 3) Initially the friction is much much smaller than the weight so acceleration is high 4) Initially the speed increases at a decreasing rate. 5) It eventually reaches terminal velocity which is its maximum speed. 6) Since friction is proportional to speed the friction grows and eventually it balances the weight 7) So the forces are no longer unbalanced 8) So unbalanced force = 0. 9) Terminal velocity is independent of the shape of the object 10) The acceleration drops to 0 when it is travelling at terminal velocity. 11) The speed remains constant throughout the whole journey 12) This occurs due to friction (this force is due to drag or air resistance)

velocity

Time Without air resistance

velocity

time with air resistance

The speed increases at a decreasing rate. It eventually reaches terminal velocity which is its maximum speed. Initially the acceleration is 9.8m/s/s. Initially the friction is much much smaller than the weight so acceleration is high The acceleration drops to 0 when it is travelling at terminal velocity. This occurs due to friction (this force is due to drag or air resistance)

Practical 212

Since friction is proportional to speed the friction grows and eventually it balances the weight So the forces are no longer unbalanced So unbalanced force = 0. At terminal velocity friction is balanced by the weight of the object. For a human terminal velocity is about 50 m/s With a parachute this may be reduced to about 5 m/s Link

Practical 220

NAME ______________________________________________________

Macleans College IGCSE Physics Practical f=ma

Equipment: Trolley, pulley, string, 20 g slotted masses, stopwatch Instructions 1. 2. 3. 4.

Set up the gear as shown below Measure the height, h, of the 20g mass above the floor (in metres) Time the mass to reach the floor (and pull the trolley from rest) Use a=2h/t2 to work out the acceleration in ms-2 trolley pulley bench mass

Mass (kg) 0.02 0.04 0.06 0.08 0.10 0.12

Weight (N) 0.2 0.4

height (m)

Acceleration ms-2

10. Plot a graph of weight (vertical axis) against acceleration

Practical 220

NAME ______________________________________________________

Weight (N)

0.0 Acceleration (ms-2)

11. What can you conclude about the weight and acceleration of the trolley? 12. Explain how we could improve this experiment

LO Plot extension/load graphs and describe the associated experimental procedure

Practical 221

NAME ______________________________________________________

Macleans College IGCSE Physics Practical A = f/m Equipment: Trolley, pulley, string, 20 g slotted masses, 5x50 g slotted masses, stopwatch, electronic balance Instructions 1. 2. 3. 4. 5.

Set up the gear as shown below Calculate the total moving mass ( trolley, all slotted masses and the 20g mass) Measure the height, h, of the 20g mass above the floor (in metres) Time the mass to reach the floor (and pull the trolley from rest) Use a=2h/t2 to work out the acceleration in ms-2 trolley

50 g masses pulley

bench 20 g mass

6. Write your results in the table 7. Remove a 50g mass from the trolley and repeat the above 8. Continue until after all 50g are removed Total moving mass (kg) Weight (N)

height (m)

Time (s)

Acceleration ms-2

10. Plot a graph of acceleration (vertical axis) against total moving mass

Practical 221

NAME ______________________________________________________

Acceleration (ms-2)

0.0 total moving mass (kg)

11. What can you conclude about the total moving mass and acceleration of the trolley? 12. Explain how we could improve this experiment

LO Plot extension/load graphs and describe the associated experimental procedure

Practical 240

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Hooke’s law Equipment: clamp, retort, spring, metre ruler, 50 g slotted masses Instructions 1. 2. 3. 4. 5. 6. 7.

Set up a retort stand with a clamp Suspend one end of the spring to the clamp Attach a 50 g base weight to the other end. Record the position of the base in a table as shown Complete the table below Calculate Load ( = mass x 10 ) Calculate Extension (= new position – original position ) Mass (kg) 0.05 0.15 0.20 0.35 0.40 0.50

Position (m)

Load (N) 0.5

spring

weight

Extension(m) 0

10. Plot a graph of extension (vertical axis) against load

extension (m)

0.0

1.0

2.0

3.0

4.0

5.0

load (N)

Practical 240

NAME ______________________________________________________

11. What can you conclude about the load and extension of the spring? 12. Predict the extension if a load of 2.5N was used. 13. Predict the load required to give an extension of 0.095m 14. Predict the mass required to give an extension of 0.115m 15. Describe Hooke’s Law 3.03 16. Does a ‘limit of proportionality’ exist for this spring? 17. Explain your answer

Duplicate graph if required

extension (m)

LO Plot extension/load graphs and describe the associated experimental procedure

Practical 248

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Equilibrium 1 Equipment: metre ruler, 50 g masses, pivot (thin card, two wooden blocks), electronic balance, objects to weight (eg keys, pencil case, metal cubes (large), wooden block to support larger objects

Instructions 1. Make up a table to enter your data 2. Balance the ruler on the pivot over the 50.0 cm mark (approx.) (if necessary move the ruler until it balances or add tape at one end) 3. Place the 50 g mass at the 30.0 cm mark 4. Place your object on the rule and slide it left or right until it balances 5. Measure the length ‘Y” 6. Use the relationship m 1 d 1 = m 2 d 2 to determine the mass of the object 7. Measure objects with an electronic balance 8. Determine the percentage error using 100% x mass from calculation / mass from balance 9. Repeat for 5 other items (eg pencil, scissors)

LO Demonstrate understanding that weights (or masses) may be compared using a balance Tabulating results

Practical 249

Macleans College IGCSE Physics Practical Equilibrium 2 Equipment: metre ruler, 50 g slotted masses, pivot (thin card, two wooden blocks)

Instructions 1. 2. 3. 4. 5. 6. 7.

Read through these instructions before you begin Balance the ruler on the pivot over the 50.0 cm mark (approx.) (if necessary move the ruler until it balances or add tape at one end) Place the 150 g mass at the 30.0 cm mark Place the 100 g mass at the 60.0 cm mark Place the 50 g mass on the ruler so they all balance Record the results in a table as shown Position of pivot = 50.0cm ACW = anti clockwise CW = clockwise

Position of 150g 100g 50g 30cm 60cm ?

Distance from pivot 150g 100g 50g 10cm 10cm ?

Moment about pivot 150g 100g 50g 3000 gcm 1000 gcm ? ACW CW

Total moment zero

8. Repeat for 4 other balanced situations (vary position and/or mass) 9. Draw a force diagram of one of your situations and show the calculation for the net moments about the pivot point (ref p50) EXTENSION

Build a balanced toy and take a photo of it

LO Perform and describe an experiment (involving vertical forces) to show that there is no net moment on a body in equilibrium

Practical 260

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Locating the Centre of gravity Gear: card, scissors, pin or nail, plumb line Aim: to determine the position of the centre of mass of a plane lamina (or card) Instructions 1) 2) 3) 4) 5) 6)

Cut out a shape on cardboard so that it has an area of about half a page Make a hole near the edge of the card Put the pin or nail through the hole so the card freely hangs from it Hold a ‘plumb line’ next to the hole. Trace the vertical line on to the card. Use a ruler to mark the line clearly

7) Make another hole in a different part of the card (try rotating 120o) 8) Repeat and obtain a different line on your card 9) Find their intersection – this should be its cog

10) Repeat with a third hole 11) If you have been working carefully, this line should pass through the same point as the other two. 12) To check your result, hold the card horizontal on your fingertip. 13) If your finger is directly below your cog then the card should balance. 14) Explain why the card balances at the cog

LO Perform and describe an experiment to determine the position of the centre of mass of a plane lamina

Practical 280

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Explain the Toy Gear: variety of toys, stopwatch, ruler, tape, 10g masses Instructions Choose a toy. Observe how it is used. Spend a few minutes thinking about the energy used and produced. For example Does it use elastic energy? If so where and what does it do? Where did it originate? Was gravity needed? How many energy conversions were involved? What would be needed to make the toy work ‘better’? Prepare a 3-5 minute speech to explain the physics of the toy

Test your ideas by altering some parameters (not permanent) -for instance tape 0.5 g mass to its side - increase the slope of the ramp slightly -change the surface material (carpet instead of table top)

Practical 282

NAME ______________________________________________________

Macleans College

IGCSE Physics Practical Loop the loop track & marble Gear: track, marbles, ruler Instructions marble

1.

2.

Place the marble at the top of the track and release. It should roll and complete the track. Repeat at a slightly lower starting height. Continue until the ball cannot finish the whole length of the track. What is the minimum height for which the ball finishes the track without leaving it? Try different marbles. Is the size important? Give several reasons why the ball does not finish the track.

EXTENSION 3. Determine a relationship between the radius of the circle and the minimum height for which the ball can complete the track

Practical 284

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Newton’s Cradle Gear: Newton’s Cradle, ruler Instructions

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Pull one ball back a few centimeters and release to strike the stationary set of balls. Observe the first bounce only. How many balls continued in the same direction? Did it (they) rise to the same original height? Measure and record both heights. Try with different number of balls. How do the heights compare? Did the same number of balls leave compared to the original number of balls that struck the stationary set? Was there any occasion where a different number left the set? Can you think of a reason why (e.g. if two balls strike a set why doesn’t one leave)? What would happen if the balls were made of putty instead of steel?

Animation

Practical 300

NAME ______________________________________________________

Macleans College IGCSE Physics Practical

Hot and Cold Gear: 2 x 250mL beakers stirring rod thermometer Instructions Record the temperature of 20 mL tap water Record the temperature of 20mL warm water Predict the temperature when they combine. Try it. Can you explain the result?

Practical 310

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Thermometers & Ice Aim: to observe temperature changes Gear: Thermometer, ice, jug, stopwatch, Instructions 1. 2. 3. 4. 5. 6.

Place a thermometer in an empty beaker Record the temperature every 15 s for 6 minutes After 60s put the bulb on a cube of ice After 120s the bulb on a cube of ice Add 20mL tap water to the ice and continue recording every 15 s for 2 minutes Add 20 ml hot water continue recording undisturbed every 15 s for 2 minutes

Practical 330

NAME ______________________________________________________

Macleans College IGCSE Physics Practical SPECIFIC HEAT CAPACITY OF WATER Gear: ammeter, power pack, stop watch, thermometer, polystyrene cup, polystyrene lid, measuring cylinder and nichrome wire heating coil. Aim: to find the specific heat capacity of water. Specific heat capacity of water is the amount of energy required to raise the temperature of 1kg of water by a degree Celsius What to do: 1. Set up the equipment as shown below

2. 3. 4. 5. 6. 7.

Measure 50ml of water and pour it in the polystyrene cup. Measure and record the initial temperature of the water. Set the power supply voltage to 12 V DC. Switch on the circuit and start the stop watch concurrently. Record the ammeter reading Switch off the power supply after 5 minutes, stir and record the water temperature.

Results and analysis • Draw a suitable table to record all the results • Calculate the heat energy dissipated by the nichrome coil in 5 minutes • How much heat energy is gained by water • Calculate the specific heat capacity of water. Discussion • Find the “official” value for the specific heat capacity of water and compare it with your calculated value. • List the ways in which the accuracy of the calculated value for the specific heat capacity can be improved.

Practical 350 NAME ______________________________________________________ Macleans College IGCSE Physics Practical

Determining the latent heat of fusion of ice

0.01

Gear: 100mL measuring cylinder; 250mL beaker, scales, thermometer, ice cube, stopwatch 1. Measure the temperature of 100 mL water in a 250 mL beaker (or calorimeter) 2. Determine the mass of an ice cube (weigh on electronic balance) 3. Put the ice cube into the water and stir it until it completely disappears (stir with a stirring rod not the thermometer) 4. Re-measure the temperature 5. Calculate ∆T the difference in the temperatures We know that c = 4200, m = 0.1 kg (= 100 mL) 6. Use H = mc∆T to determine the heat gained by the ice. 7. Use H = mL to determine L (the latent heat of fusion of ice)

Practical 400

Macleans College IGCSE Physics Practical Sound and the oscilloscope Gear: signal generator oscilloscope, microphone, connecter, tuning fork set, large speaker cone (with out the box covering), connecting wires, alligator clips, balloon Aim To observe sound waves and some of their effects Instructions Connect the signal generator to the oscilloscope and speaker. Observe the wave forms produced by different electrical signals and compare them to the sound that you hear. 1. 2.

List two ways that the electrical signal and sound are similar List two ways that the electrical signal and sound are different

Connect the microphone to the oscilloscope and observe the wave forms produced by each sound. These questions refer to the pattern seen on the oscilloscope screen 3. 4. 5. 6. 7. 8.

How are loud sounds different from quiet sounds? Which objects produce simple repetitive waves? Draw a sound wave produced by a tuning fork of low frequency. Draw a sound wave produced by a different tuning fork with a higher frequency. What diagrammatical feature have you drawn to show that the two waves are different? How do the waves that you have drawn differ from a real sound wave?

The Oscilloscope This is a useful device to measure the frequency and voltage of an electrical signal. A spot sweeps from left to right across the screen. A 1 V signal makes the spot move up one 1V. This is found by the amplitude x gain. The frequency can be found from the wavelength x timebase. The gain is the number of squares from the middle of the wave to the top. The timebase is the time for the spot to move right one square. In this example the time base is 10 ms (per square) and the gain is 2 V This signal then represents a peak voltage of 2.3 (squares) x 2 V = 4.6V and a period of 10 (squares) x 10 ms = 100 ms. Since f = 1/T then f = 1 / 0.1 s = 10 Hz Set the timebase to 10 ms on the oscilloscope and set the frequency of the signal generator to 100 Hz. Accurately draw the wave on a grid (your graph paper will do) and state important features.

Practical 410

NAME________________________________________________________

Macleans College IGCSE Physics Practical Types of wave Gear: thin long slinky, wide slinky, stop watch, metre rule Aim To observe two different types of waves

Instructions Make clear labelled diagrams in your practical books 1.

Hold one end of a thin slinky on the ground. Have your partner hold the other end on the ground. Stretch it about 1 m.

2.

Wobble your end perpendicular to the slinky and horizontal with the ground. Make the frequency about 1 Hz.

3.

Observe the slinky just before the wave reaches your partners hand.

4.

Draw this pattern and show two or three waves.

5.

Repeat with a slightly higher frequency – it is important to get the same length of the slinky.

6.

Repeat both several times so that you get an accurate measurement of the wavelengths.

7.

Show the measurements of the wavelengths clearly on your diagram.

8.

Repeat the above and show the wave after the reflection off your partner’s hand.

9.

Repeat the above and use a stopwatch to determine the period of ten oscillations then from this determine the frequency.

10.

Repeat for the higher frequency.

11.

Repeat all of the above using the wide slinky except push it forwards and backwards instead of side to side motions.

Extension Determine the speed of the waves from the information that you have drawn and labelled. Research: What is the speed of sound in air and water?

Practical 450

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Reflection Gear: flat mirror, paper, drawing pin board, 2 optical pins, ruler Aim: to determine the position of an image in a flat mirror If you put a pin in front of a flat mirror, you see an image in the mirror. The image appears to be behind the mirror. To find its position, you have to ‘point’ lines at it from two different directions and find out where they meet.

x

Instructions 1) 2) 3) 4) 5) 6) 7)

Put your paper on the drawing pin board. Stand the mirror upright in the middle of the paper. Draw a line along the front of the mirror with a pencil. Insert a pin upright about 10 cm in front of the mirror, x Mark its position on your paper. Put the ruler on your paper -near position A. Rotate your ruler until its edge lines up with the image of the pin (you will see the edge of the ruler in line with the image). 8) Draw a line along the edge of the ruler (line A).

9) Move the rule to position B. 10) Again, move it until one edge lines up with the image of the pin. 11) Draw a line along the edge (line B). 12) Remove the pin and mirror from the paper. 13) Extend the two lines until they cross. This is where the image seems to be. 14) Label this point I. Check your results: 1) Draw a line from X to I and measure halfway. 2) This is where the mirror should be. Measure the difference. 3) Put the mirror and the pin back into their original positions. Hold a second pin upright behind the mirror at the point where your two lines cross. Look into the mirror. You should see the top half of this second pin exactly in line with the image of the first pin. The pin should stay in line with the image even when you move your head from side to side. 4) How accurate were your measurements?

Practical 455

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Multiple Reflections Gear: two flat mirrors, paper, protractor, optical pin, ruler Aim: to determine the equation that relates the number of images, n, with the angle, Ɵ between two flat mirrors Instructions 1) 2) 3) 4) 5) 6) 7) 8) 9)

On a flat sheet of paper mark a mirror line X-Y Mark 5 lines from X so that they form different angles Ɵ; 22.5o ,45o ,60o 72o and 90o Use the 90o lines and put two mirrors on them (they should face each other) Mark an x on the sheet between the mirrors and put the optical pin there. Can you see all three images when you look in any mirror (keep mirrors vertical)? Change the angle and recount the number of images you observe. Continue using other angles Can you make an equation that relates n and Ɵ? What would happen if the mirrors were parallel and facing each other?

X

X

Practical 460

Macleans College IGCSE Physics Practical Tracing light rays through a perspex block Gear: power pack, ray box, perspex rectangular block, single slit, protractor Aim: to observe the path of light in a transparent rectangular block Instructions 1 Place the block in the middle of the paper. Draw round the block to mark its position. 2

Point the ray-box (with a thin beam of light) into the block.

3

Angle the ray so that it goes in and out of the block as in the diagram.

4

Using a pencil, mark the path of the ray going into the block. Two small crosses are good for this – drawn as far apart as possible. Then mark the path of the ray leaving the block.

5

Take the block and the ray box away. Using your crosses as a guide, draw in lines to show the path of the ray as it enters and leaves the block. Join up the lines to show the path of the ray inside the block.

6

Measure the angle of incidence of the ray entering the block (angle θ i in the diagram). Then measure the distance between the paths of the rays entering and leaving the block (distance d in the diagram).

7

Repeat for at least six values of θ i and put your results in a table.

8

Plot a graph of d against θ i. Can you draw any conclusions from the graph?

Practical 460

d/cm 0.8 1.0 1.4 1.8 2.6

theta(degree) 21 28 38 47 57

sin (theta) 0.3583 0.4694 0.6156 0.7313 0.8386

d/cm 0.8 1.0 1.4 1.8 2.6

Practical 10a

Practical 465

NAME ______________________________________________________

Refractive index of a semi-circular block Gear: power pack, ray box, glass semi-circular block, single slit, protractor, graph paper Aim: to determine the refractive index of perspex Instructions 1 Place the block in the middle of the paper. Trace around its edge. 2 Measure the diameter and mark the centre with an A 3 Shine a single ray of light at A 4 Mark the point where it emerges from the block (label) 5 Repeat for 5 different angles 6 Remove the block and draw each ray. 7 Draw the normal 8 Measure i and r for each (write in 9 Calculate sin i and sin r 10 Plot sin i (vertical axis) against sin r 11 Write a conclusion

Practical 10a

Practical 467

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Refractive index of a glass-block Gear: power pack, ray box, perspex rectangular block, single slit, protractor, graph paper Aim: to determine the refractive index of a glass rectangular block Instructions Copy and complete a table such as this

Angle of incidence 10 25 30 40 45 60 75 85 1 2 3 4 5

6 7 8 9 10 11 12

Angle of refraction

Place the block in the middle of the paper. Trace around its edge. Point a thin beam of light into the block (angle of incidence = 30o) Mark the entry point A Mark the point where it emerges from the block (label it 30o) B Repeat for different angles (10, 25, 40, 45, 60, 75, 85) but always use entry point A Remove the block and draw each refracted ray. Measure the angle of each refracted ray Determine sin i and sin r Plot sin i (vertical axis) against sin r Calculate the gradient What does this gradient tell us? Write a conclusion

Sin i

Sin r

A

Practical 470

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Total Internal Reflection Gear: power pack, Light box –single slit Glass blocks (perspex scatter too much light), Students need protractor and paper Aim: to observe total internal reflection by reflection in transparent blocks In this experiment, you pass a ray of light in and out of a right-angled prism so that it reflects off an inside face. Instructions 1

Place the prism in the middle of the page. Draw round the prism to mark its position.

2

Set up the ray box as shown. Make the ray strike one of the short faces of the prism ‘square on’ as in diagram A. How can you do this accurately?

3

Mark the path of the ray going into the prism. Mark the path of the ray leaving the prism. Then mark the point where the ray reflects from the inside face of the prism.

4

Remove the prism and the ray box. Draw in the path of the ray going into, through and out of the prism.

In this part of the experiment, you change the path of the ray so that it reflects off two inside faces. 5

Repeat the steps above – only this time make the ray meet the prism as in diagram B.

6

When light reflects from a mirror, the angle of reflection is equal to the angle of incidence (see diagram C). Is this law also true for light reflected from the inside face of a prism? Use your ray-tracing experiments to find out.

Practical 475

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Critical Angle Gear: power pack, light box (ray box, single slit), semi circular glass block, semi circular (hollow plastic) dish with water. Students need their protractor. Aim: to measure the critical angle of perspex If a ray of light meets the inside face of a glass block as in the top diagram, some of the light is reflected and some is refracted. Increase the angle of incidence and eventually the refracted ray will disappear (90o to the normal) as in the diagram below.

The angle shown is called the critical angle. At greater angles than this, there is no refracted ray. All the light is reflected. In this experiment, you will measure the critical angle of glass, perspex and (possibly) water.

Instructions 1. 2. 3.

4. 5. 6.

Place the block in the middle of the paper. Draw round the block to mark its position. Find the centre of the semi-circle. Then draw in the normal in line as shown in the diagram (right). Set up the ray box as described in the previous two experiments. Angle the ray as I diagram A, so that it goes straight through the curved faced of the glass block and strikes the centre of the semicircle. Increase the angle until the refracted ray has just disappeared. Mark the position of the ray. The ray is now striking the surface of the block at the critical angle. Remove the glass block and the ray box. Draw in the path of the ray. Measure the critical angle. Repeat the experiment and find an average value for the critical angle.

If time permits repeat for other transparent material. Extension Explain this formula and use it to derive a formula for determining the critical angle. n 1 sinθ 1 = n 2 sinθ 2

Practical 475

NAME ______________________________________________________

Marks Label incident ray and refracted ray Label block AND normal Arrows go towards middle point AND away from middle point Critical angle = 43 or 42 degrees

Practical 480

NAME ______________________________________________________

Macleans College IGCSE Physics Convex lens Equipment: power pack, bulb, lens, lens holder, metre ruler and screen Method: 1. Set up the following

2. 3. 4. 5.

Adjust the position of the lens to get a clear image on the screen. Record x and y in a table as shown below Repeat for five more values of x (caution: some x values may have very large y values). Determine the reciprocal of x and the reciprocal of y 1 + 1 y )

6. Determine the sum of these reciprocals ( x

1 1+1 7. Determine the reciprocal of the sum of the reciprocals ( x y )

Results Copy and complete the table: x

y

1/x

1/y

1 + 1 y x

1 1+1 x y

8. Check the units for each column 9. Determine the focal length of the lens by measuring the distance from the lens to a screen. The image on the screen must be clear and the object must be very far away e.g. music block. 10. Comment on your last column of the table.

Practical 485

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Focal length Gear: thick convex lens, thin convex lens, lens holder, screen (white card), metre rule When parallel rays of light go through a convex lens, they come together at a point called the focus. The distance from this focus to the lens is the focal length.

Rays from anything a long way away are very nearly parallel. If you use a convex lens to focus rays from a distant building or tree, you can see a small image on a screen. If the image is sharp, the screen is at the principal focus. The distance from the lens to the screen is the focal length.

Instructions 1 Arrange the lens, screen and metre rule as in the diagram. Light from a window must be able to pass through the lens and reach the screen. The experiment works best if the lens and screen are in the darkest part of the room, opposite the window. 2

Move the screen backwards or forwards until you see a clear image of a distant tree or building.

3

Measure the distance from the lens to the screen. This is the focal length of the lens.

4

Repeat the experiment at least three times. Find an average value for the focal length.

5

Find out by experiment which has the longer focal length, a thick lens or a thin lens.

6

find out by experiment which gives the bigger image on the screen, a thick lens or a thin lens.

Practical 490

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Dispersion Gear: triangular GLASS prisms, power pack, ray-box with single slit, paper, ruler, screen, protractor Aim Each wavelength of light has a unique refractive index. When white light pass through different material the individual colours can be separated. This is called dispersion. You are to investigate this phenomenon.

Instructions Copy the table into your practical book.

1.

Place the triangular prism in the middle of your page.

2.

Shine a thin beam of white light into the prism so that dispersion is observed. You may need to rotate either the prism or the ray box about the middle of the page.

3.

Carefully draw the outline of the prism and the path of the light rays entering and emerging from the prism.

4.

Draw the probable path of the incident ray if the prism was absent (extend this to the end of your page). This is called the ‘straight through’ line.

5.

Carefully draw and extend the lines for the red, green and violet rays so they are 5-8 cm in length.

6.

Use your protractor to measure their angles from the ‘straight through’ line and record the data into your practical book.

7.

Repeat the above using a different type of prism (either glass or perspex).

8.

List ways to improve your results

Practical 500

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Electrostatics Gear Electroscope, woollen cloth, perspex, plastic, nylon or glass (rods or sheets), OHT sheets Aim To observe some phenomena related to electrostatic charge These activities are weather dependent. They work best on dry days. Humid or damp days give poor results. Instructions

1) Read all of theses instructions before you start 2) Rub a plastic rod with a woollen cloth 3) Hold the plastic near the cap of the electroscope. 4) Observe the leaf. 5) Repeat but this time touch the cap of the electroscope. 6) What difference does this make? 7) Repeat and touch the cap two more times. 8) Does this have any effect?

9) Repeat 1) with perspex and a woollen cloth 10) Do you get the same result? 11) Find and list objects that do have the same effect (state what they were rubbed with). 12) List objects that do not (state what they were rubbed with). Tabulate your results in a sensible way.

Extension Explain what is meant by induced charges (p 180 Pople).

Practical 508

NAME______________________________________________________________

Macleans College IGCSE Physics Practical

* Series or parallel circuit Gear: Power packs, connecting wires, bulbs, voltmeter, ammeter and switch

Carry out the following instructions. Record your observations and readings in your Practical Book. Copy the following table.

Set up Fig. 1.1

Practical 508

NAME______________________________________________________________

Practical 510

NAME ______________________________________________________

Macleans College IGCSE Physics Practical Combined resistance Gear: Power packs, bulbs, voltmeter, ammeter, switch and connecting wires

Practical 510

NAME ______________________________________________________

Practical 510

(k)

NAME ______________________________________________________

Summarise your findings.

Practical 511

NAME ______________________________________________________

Macleans College IGCSE Physics Practical IV graphs Gear: power supply, resistors (lamp, 100 ohm, motor), ammeter, 3 connecting wires Aim To observe current-voltage characteristics for some resistors Instructions 1.

Set up the circuit shown.

2

Draw a circuit diagram for it.

3

Copy and complete this table. Potential difference 0.5 1.0 2.0 4.0 6.0 8.0

Current

Current

Current

4 5 6

Check your current numbers have the same d.p . Include units in your table Plot a graph of current (vertical) against voltage. Repeat for different resistors

7

What can you say about the resistance of a lamp, motor, carbon resistor (?)

Practical 516

NAME______________________________________________________________

Macleans College IGCSE Physics Practical Potential Divider Gear: power pack, voltmeter (DMM), fixed resistor (approx 20 ohm), connecting wire, and rheostat (large). In this experiment you are to investigate the behaviour of a potential divider. Instructions 1. Read the top right hand panel page 245 Pople. 2. Set up the lower circuit using the available rheostat and fixed resistor. 3. Make up a table showing the position of the slider on the rheostat and the output voltage. Show six different positions for the length.

4. Swap the position of the fixed resistor and rheostat. The output voltmeter is across the fixed resistor. 5. Repeat step 3 above. 6. Explain how a rheostat can be used as a potential divider.

Practical 521

NAME______________________________________________________________

Macleans College IGCSE Physics Practical Magnet Field of a bar magnet Aim: To observe magnetic field lines around bar magnets Gear: 2 bar magnets, paper, iron filings, flat booklets

Instructions: 1. Place paper over a bar magnet as shown. Sprinkle iron filings. Tap paper. 2. Observe patterns 3. Record field lines Bar magnet under sheet of paper

4. Repeat for the following magnet arrangements (a) S

N

N

(b)

S

N

S

(c)

S

N

S

N

S

N

(d)

S

N

N

S

Practical 525

NAME______________________________________________________________

Macleans College IGCSE Physics Practical Magnetism 2 Aim: To plot magnetic field lines and show their directions using a plotting compass Gear: bar magnet and charm (plotting) compass Instructions: 1. Place bar magnet in the middle of your page & trace the edge 2. Place a charm compass touching the magnet on your page. 3. Slide the compass along the magnet. Observe the arrow changing directions 4. Slide the compass to one corner so that it points away from the magnet. 5. Mark that end of your compass “N” 6. Observe where the tip of the arrow would line up on your sheet. 7. Use a sharp pencil to mark your sheet with a dot “.” where the tip of the arrow would be. 8. Slide the compass so the tail of it is directly over the dot. 9. Repeat steps 6-8 until you are off the sheet or return back to the magnet. 10. Slide the compass to another position on the magnet 11. Repeat steps 6-10 until you have 5-6 curves on both sides of the magnet 12. Draw in the curves and show the direction of the field lines

Step 4

Step 6

S

N

S

N

Your diagram might look like this. Extension: Place a second magnet 20 cm away and repeat the process. What do you think the pattern would appear now?

Practical 540

NAME______________________________________________________________

Macleans College IGCSE Physics Practical Mapping the field round a magnet Gear: bar magnets, paper, small compass (plotting compass) The space around a magnet where you can find its magnetism is called a magnetic field. If you sprinkle iron filings around a magnet, you can see the field pattern. You can also plot the field pattern using a small compass.

1

Put the magnet in the middle of the paper. Draw round the magnet to mark its position. Keep the magnet and paper in the same place for the rest of the experiment.

2

Put a dot on the paper near one end of the magnet. Place the compass so that one end of its needle is next to the dot. Mark the position of the other end of the needle with another dot.

3

Move the compass so that the first end of the needle points to the last dot you made… and so on until you have a row of dots which reaches the magnet again or the edge of the paper. 4

Join up the dots with a smooth curve. You have now drawn a field line.

5

Repeat from a different dot by the magnet. Do this about ten times until you have drawn a full pattern round the magnet.

More things to do 6

Find the field patterns around these magnets:

(a)

(b)

Practical 542

NAME______________________________________________________________

Macleans College IGCSE Physics Practical

Force on a current carrying wire Gear: power pack, large horseshoe magnet, long wire

1. 2. 3. 4. 5. 6. 7.

Place the long wire in the magnet as shown. Switch on briefly. Observe the movement. Reverse the polarity of the power supply. Observe the movement. Reverse the polarity of the large magnet. Is this what you expected?

List three ways to make the magnetic force stronger.

Practical 543

Electromagnetism 1

NAME______________________________________________________________

Macleans College IGCSE Physics Practical

Oerted’s Experiment Aim: To show that the magnetic field is at right angles to the current Gear: long wire, short wire, power supply, charm compass, lamp Instructions Place a compass on the table. Use one long wire (and a short wire) to connect a lamp to a DC power supply. Test that it works- Turn off. Move the long wire over the compass so that the needle is parallel to it. Turn on and determine the direction of the magnetic field. Repeat with the compass above the wire. Try different situations Turn the long wire so it is vertical and place the compass as close as possible to it. Determine the direction of the magnetic field Reverse the polarity and repeat. Does the magnetic field remain in the same direction?

Practical 560

NAME______________________________________________________________

Macleans College IGCSE Physics Practical

Electric Motor Gear: crocodile clip, 2V power supply, Hodson Electric Motor Kit,

Extension: plastercine, string, stopwatch, electronic scales The electric motor is an application of electromagnet force and current. Instructions 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Check that the ‘kit’ contents are complete before you start Align and press the two halves of the rotor together until they ‘click’ (fig.1) Insert axle to ensure rotor spins freely Remove axle and wind the coil with wire. Form the commutator and hold in place with 2 rubber rings (fig. 2) Thread wires through end plate and form the brushes with red and black wire (fig. 3). Fit the two ends to the metal frame with the elastic band (fig. 4). Fit the two magnets with opposite poles facing each other (fig. 5). Fit the axle and fit the rotor between the ends and between the brushes Check that the brushes press gently against the commutator loops. Check that the rotor rotates freely 360o Connect to a 2V DC supply (you may need to give an initial flick to start).

Extension Using a small piece of adhesive tape attach a length of thread 1500 mm long to the rotor tube (opposite end to the commutator). Hold the motor on its side on the edge of a bench so that the string hangs down to the floor and free from obstructions. Tie a small mass to the end of the thread and connect the motor to the power supply. Have some slack in the thread and start the motor. As soon as the mass begins to lift from the floor use a stopwatch to measure the time it takes to raise a mass (eg 10 g) a height of (1 metre, perhaps). Calculate the power of the motor in watts.

Practical 560

NAME______________________________________________________________

fig. 1

fig. 2

fig. 3

fig. 4

fig. 5

Practical 561

Efficiency of a motor

NAME______________________________________________________________

Macleans College IGCSE Physics Practical

Aim: to determine the efficiency of an electric motor.

Gear: DC motor, ammeter, switch (or double throw switch), power supply, spool with cotton and mass, retort stand etc. Instructions 1. Set up a motor in series with an ammeter, switch and 6V DC supply 2. Clamp to a retort stand on a bench. 3. Tape a 1.2 m length of cotton with 10 g mass. 4. Switch on to wind up the mass. 5. Stop immediately 6. Unwind by reversing the terminals (or use a double throw switch) 7. Record the current and voltage as the mass rises (repeat a few times if necessary) 8. Measure the height the mass can travel. 9. Time how long it takes to rise to that height 10. Use E = mgh to calculate work output 11. Use E = VIt to calculate work input

12. Determine the efficiency =

𝑒𝑒𝑒𝑒𝑒𝑒 𝑜𝑜𝑜𝑜𝑜𝑜 𝑒𝑒𝑒𝑒𝑒𝑒 𝑖𝑖𝑖𝑖𝑖

x 100%

13. Repeat using different voltages eg 2V 4V 6V 10V 14. Does the voltage affect the efficiency?

DC Supply

Practical 570

NAME______________________________________________________________

Macleans College IGCSE Physics Practical Capacitor Gear: Y10 electronics kit (with resistors, transistor, capacitors and 9V battery), iron wool In this experiment you are to investigate the behaviour of a capacitor. Instructions 1. Read the bottom half of page 246 Pople. 2. Set up the circuit using an LED instead of the 6V lamp 3. Draw this circuit diagram carefully and label the parts. 4. Observe the LED when the switch is turned on. 5. Reset the capacitor and repeat a few times 6. Record your observations. 7. Explain how the capacitor is used in this circuit. 8. Change the capacitor and explain how the different capacitor affects the circuit.

Practical 571

NAME______________________________________________________________

Macleans College IGCSE Physics Practical LDR Gear: Y10 electronics kit (with resistors, transistor, LDR and 9V battery), iron wool In this experiment you are to investigate the behaviour of a light dependent resistor. Instructions 1. Read the top half of page 246 Pople. 2. Set up the circuit using an LED instead of the 6V lamp 3. Draw this circuit diagram carefully and label the parts. 4. Observe the LED when the LDR is in bright light (under lights) and in the dark. 5. Record your observations. 6. Swap the LDR with the 10 k ohm resistor. 7. Explain how this affects the LED. 8. Draw the circuit diagram carefully and label the parts.

Practical 572

NAME______________________________________________________________

Macleans College IGCSE Physics Practical Thermistor Gear: Y10 electronics kit (with resistors, transistor, thermistor and 9V battery), iron wool, beaker of water, hair dryer In this experiment you are to investigate the behaviour of a thermistor. Instructions 1. Read page 247 Pople. Do not set up the circuit. 2. Copy the top circuit diagram on page 247 Pople using an LED instead of the 6V lamp, a 9V battery instead of the 6V supply, a thermistor instead of the LDR and add an ammeter in series with the LED. 3. Set up your circuit and record observations. 4. Use cold water and a hair dryer to change the temperature of the thermistor. 5. Explain how a thermistor changes with temperature.

Practical 573

NAME______________________________________________________________

Macleans College IGCSE Physics Practical Transistors Gear: power pack, ammeter, connecting wire, iron wool, npn transistors (mounted), 6-12V lamp, 2 x 1.5 V cells In this experiment you are to investigate the behaviour of a transistor. Instructions 1. Read page 244 Pople. 2. Set up circuit A on Page 244 Pople and add an ammeter in series with the lamp. 3. Record your observations. 4. Draw circuit B with ammeter. 5. Set up circuit B and turn on then off the 1.5V supply to the base of the transistor. Repeat until you know what that part of the circuit does. 6. Record your observations. 7. Use the terms ‘base–emitter’ and ‘collector–emitter’ to explain the behaviour of an npn transistor.

Practical 580

Macleans College IGCSE Physics Practical Electronic Circuits 1 Set up your circuit with a 1K variable resistor - Draw a circuit diagram for it

LED Red (Up) Black (Down)

Resistor BrownBlackRed (Gold)

Variable Resistor

Transistor White (left) Red (Up) Black (Down)

In light the LDR prevents the LED from working. In dark the LDR allows the LED to work. Describe what happens to the LED when the resistor is turned from minimum to maximum resistance (or vice versa). Determine the resistance when the LED just starts to operate (or when it just stops operating). Explain why.

The transistor turns on when the voltage across Vbe > 0.6V The total V across the fixed resistor and variable resistor is 9V If the resistance of the variable resistor greater than about 84 ohms the voltage is greater than 0.7 V This will cause the transistor to turn on so the LED lights up. If the resistance of the variable resistor less than about 84 ohms the voltage is less than 0.7 V This will cause the transistor to turn off so the LED is off.

Set up this second circuit- use your hand to darken the LDR / use a lamp to provide more light

1

It lights up in the dark

2 1 2 3 4 5 6 7

EXPLAINATIONS LDR has low resistance in light and high resistance in the dark In the classroom the light level is low (darkish) So LDR has high resistance So VLDR = VBE is high (>0.6V) So Transistor turns on So LED is on Shine light (from torch) onto LDR lowers the resistance and may drop V BE below 0.6V so LED turns off

3 With 22K replacing 1K then VLDR has a much smaller V BE so LED probably off or needs less light (from torch) to turn off -

In dark (or in classroom), the LDR has high resistance, so its voltage is > 0.6V so transistor is turned on so LED is on. In bright light (use 12V lamp), the LDR has low resistance, so its voltage < 0.6V so transistor is turned off so LED is off. Summary: LED is on unless LDR in bright light

Replacing the 1k resistor with the 22000Ω resistor means that V LDR has lower voltage initially {it must be much darker so that the LDR resistance is much higher to allow it to get more than 0.6V or more as its share in the potential divider. e.g. 1000Ω : 100Ω = 8.2V : 0.8V 22000Ω : 100Ω = 8.9V : 0.1V (so not enough)}

2 Potentiometer replaces LDR. With the battery switch pressed on, turn the potentiometer slowly one way and the other and repeat. What use is the potentiometer in this circuit? Adjust potentiometer until LED ‘just’ stays on. Remove potentiometer and measure its resistance. This is the largest resistance to ‘just’ turn on the transistor

3 Potentiometer in series with LDR Adjust potentiometer until LED ‘just’ stays on. Move your fingers over the LDR Describe and explain what happens.

4 Temperature control Replace the capacitor with a thermistor Use a hairdryer to turn off the LED. Explain how we can use the hairdryer to turn on the LED.

4 Moisture detector Put the probes in moisture. Try using your fingers

5 Courtesy light Push the button for 2 seconds. What happens after you release the switch?

6 Delay Replace the yellow wire with the 100k potentiometer. Time it to light up. This does not work the second time as the capacitor is now charged up. Discharge it by connecting the + to – of the capacitor for a second (any bare wire will do) Repeat with the potentiometer dial in different positions. Draw a circuit diagram and explain what happens.

8 Relay These will be phased out when ssr (solid state relays) become more easily assessable. Press your finger on the battery switch - the relay clicks and both ‘grain of wheat’ lamps glow. The lamp in the yellow circuit is dim while the other lamp is bright. Take your finger off and the relay clicks off. Repeat slowly and the same happens but repeat quickly and it doesn’t. The relay acts as a latch for the white circuit. Initial push opens the latch so white circuit is open. When the switch is open the white circuit stays off until inductor (relay discharges).

In light the LDR prevents the LED from working. In dark the LDR allows the LED to work. In light, the LDR has low resistance, so its share of the voltage of the potential divider is not enough to switch the transistor on. In dark, the LDR has higher resistance, so its share of voltage is above 0.6V needed to turn the transistor on. The 22000Ω resistor means that it must be much darker so that the LDR resistance is much higher to allow it to get more than 0.6V or more as its share in the potential divider. e.g. 1000Ω : 100Ω = 8.2V : 0.8V 22000Ω : 100Ω = 8.9V : 0.1V (so not enough) 22000Ω : 2000Ω = 8.3V : 0.6V (darker, and transistor switches on)

Resistor 1kΩ

LED

Resistor 1kΩ

LED

Transistor LDR

Resistor 22kΩ 1000µF

LED

Resistor 22kΩ

Relay

Transistor Transistor 1000µF

Motor

Practical 600

NAME______________________________________________________________

Macleans College IGCSE Physics Practical

Radioactivity Gear: drawing pins Radioactive material transforms into different nuclei. In doing so it releases energy in the form of kinetic energy or electromagnetic waves. We will investigate the decay pattern by using drawing pins. The pins that point upwards can be considered as radioactive atoms and the pins that point down (angle) can be considered as decayed atoms. Instructions 1. Count the number of pins supplied to you (approx. 100-200). This is throw “0” 2. Pour them onto your table top. This is throw number “1”. 3. Count the number of pins that are pointing upwards (radioactive atoms) 4. Remove all pins that face down (decayed atoms) 5. Throw again using only radioactive atoms. This is throw number “2”. 6. Repeat several times until all of the pins are used up. 7. Continue the table for as many throws necessary.

Throw number 0 1 2 3 4 5 6

Number of radioactive atoms

Practical 600

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8. Graph the class’s number of “Number of radioactive atoms” on the vertical axis against the “Throw number”. 9. Determine the half life of this by halving the initial number of pins and finding the corresponding time. 10. Repeat for different initial values and finding the corresponding time interval.