cxc Physics lab

TABLE OF CONTENTS SBA

TITLE

EXPERIMENT

SKILL

Exp t. No

PAGE NO

1

Physical Measurements and Units

Finding volume of a Jamaican $20 coin by two different methods

O/R/R /MM

2

Physical Measurements and Units

Finding the area of a leaf

O/R/R A/I

3

Physical Measurements and Units

Finding the density an irregular object

4

Physical Measurements and Units

The effect of length on the period of a pendulum

A/I

5

Physical Measurements and Units

The effect of mass of the weight on the period of a pendulum

PD

6

MECHANICS

MM

7

MECHANICS

Finding the centre of gravity of an irregular object Finding the weight of the meter rule

8

MECHANICS

Verifying Hooke’s Law

9

Thermal Physics and Kinetic energy

Finding specific heat capacity of a metal

10

Thermal Physics and Kinetic energy

Finding specific heat capacity of concrete

11

Thermal Physics and Kinetic energy

Finding the latent heat of fusion of ice

12

Thermal Physics and Kinetic energy

Verifying Boyle’s law

A/I

13

Thermal Physics and Kinetic energy

Verifying Charles’s law

O/R/R

14

Waves and Light

Investigating the relationship between incident light and reflection

M/M

15

Waves and Light

Finding focal length of a convex lens

M/M

16

Electricity and Magnetism

Investigating the relationship between change in the length of a wire and resistance

A/I/ O/R/R

PD

2

17

Electricity and Magnetism

Investigating the relationship between change in the thickness of a wire and resistance

18

Electricity and Magnetism

Investigating the voltage characteristic of a lamp

19

Physics of the atom

Effect of distance (from the detector) on the transmission of beta radiation

20

Physics of the atom

Effect of shielding materials on the transmission of beta radiation

PD

PD

EXPERIMENT #1 TITLE: MEASUREMENTS AIM: Finding volume of a Jamaican $20 coin by two different methods DATE:

Apparatus and Materials 

Jamaican $20.00 coin (5)



Vernier Caliper



100 cm3 measuring cylinder



Pipe water

Procedure VOLUME FROM CALCULATIONS USING THE VERNIER CALIPER 1. The caliper was checked to ensure that when it is closed the readings at zero (0) 2. The diameter of the $20 coin was measured and recorded. 3. The thickness of the same coin was measured and recorded. 4. The formula for volume of a cylinder was used, (4πr2h), where h is the thickness of the coin. 5. The volume of the $20 coin was calculated. Results

Diameter of $20 coin

22.5mm

2.25cm

Thickness of $20 coin

0.25cm

0.250cm

Radius the $20 coin

11.25mm

1.13cm

TABLE SHOWING RESULTS FOR METHOD 1

Calculations for method 1

The volume of the Jamaican $20 coin is 1.34cm3 VOLUME FROM DISPLACEMENT USING THE 100ml MEASURING CYLINDER 1. 50 ml of pipe water was accurately measured into the measuring cylinder. The value was recorded in a suitable table 2. Five (5) $20 coins were added to the volume in the measuring cylinder. 3. A new volume was recorded when all the coins were in the measuring cylinder. 4. The net volume was determined and the volume divided by five (5) to the Average of one $20 coin. Results

Volume

Volume of water

100ml

Volume of 5 coin

105ml

Net volume

5ml

TABLE SHOWING RESLUTS FOR METHOD 2

Calculations for method 2 Net volume = V2 - V1 = 105 – 100 Net volume = 5ml Average volume of one coin Net volume = 5 ml = 1 ml 5

5

Average volume = 1ml

Discussion Both results were the same, this suggest that the experimenter had carried out the experiment with no error . Precautions /Possible sources of errors  Ensure Vernier caliper is set at 0  Ensure measuring cylinder is on a flat surface  Ensure to avoid paradox errors Conclusion This experiment has proven that the volume of the Jamaican $20 is 1.00cm3,using both the Vernier caliper method and the measuring cylinder method.

EXPERIMENT #2 TITLE: MASUREMENTS AIM: To find the area of a suitable leaf using a graph paper DATE:

Apparatus and Materials  Graph paper  pencil  suitable size leaf Procedure 1. A suitable leaf was used, that covered two thirds of the graph paper. 2. The leaf was positioned on the paper, held down firmly and the edges were traced around with a sharp pencil. 3. The graph paper was used to determine the size of the area of the leaf 4. The largest square are 2cm × 2cm =4 cm2 , the next smaller squares are 1 cm × 1cm2 and the smallest square is 2mm × 2mm =0.04cm2 5. The largest squares were labelled “A” and were counted and multiplied by 4 Cm2 6. The smaller squares were labelled “B” and were counted and multiplied by 1cm2 7. The smallest squares were labelled “C” and were counted and multiplied by 0.04m2 8. The areas were recorded and added up to get the total area of the leaf

Calculations

No. of “A” squares =

No. of “B” squares =

22

23

No. of “C” squares =

Total area of leaf =

× 4cm2 =

× 1cm2 =

453

129.12

88 cm2

23 cm2

× 0.04cm2 =

18.12 cm2

cm2

Precautions 

Ensure leaf does not shift

Conclusion Based on the experiment done it was proven that the area of a suitable leaf is 129.12 cm2

EXPERIMENT #3 TITLE: MEASUREMENTS AIM: To find the density of an irregular object using Archimedes principle DATE:

Apparatus and Materials 

100 ml measuring cylinder



Small stone (that can easily fit inside the measuring cylinder)



Pipe water



Triple beam balance or electronic balance



Tissue or hand towel

Procedure 1. The scale was set up and checked to ensure that it is at zero. 2. The mass of the stone was Weighed and recorded. 3. 50ml of water was measured in the measuring cylinder. 4. This was recorded as the initial volume of water. 5. The measuring cylinder was tilted to about 45 and a small stone was rolled down the sides without splashing. It was placed on a levelled surface; the new volume was noted and recorded. 6. This was recorded as the final volume of the water. Calculations Initial Volume of water =50 ml Final volume of water =70.1ml Net volume = Net volume = V2 - V1 = 70.1ml – 50ml Net volume = 20.1ml

Density P =mass/volume =23.9g/20.1ml =1.19g/ml

Precautions  Ensure that meniscus is read from eye level

Conclusion Based on the experiment done, it can be concluded that the density of an irregular shaped object is 1.19g/ml using Archimedes principle.

EXPERIMENT #4: TITLE: MEASUREMENTS AIM: To study how the length of a string affects the period of a pendulum DATE:

Apparatus and Materials  A 60 – 100 cm crochet cord or any other suitable string  A 100g/200g weight  Dark coloured marker  Meter ruler  Protractor Procedure 1. The crochet cord was tied to the weight.90cm between the top of the weight and fingers. 2. A position was marked 5cm down from the top of the cord with a marker. This was treated as the 85cm position. 3.10cm position were accurately marked from this position down towards the weight. 4. Then the cord was held vertically, then a protractor was used to ensure it is at the 90◦ mark. 5. A stop watch was used to time the oscillations, the stop watch was checked to ensure that it is at 0. 6. The cord was displaced by 50◦ and released, ten oscillations were counted at length. 7. The cord was held at the 75cm position. Procedure five was repeated until it has reached the 45cm position.

8. The results were recorded in a suitable table Results

Length (cm) 85

Period 10 oscillation 20.10

One T2 Oscillation (period/10) 2.01

Angle Of displacement 50

Mass of the bob 250

75

18.82

1.882

50

250

65

17.92

1.792

50

250

55

17.19

1.719

50

250

45

16.05

1.605

50

250

TABLE SHOWING RESULTS

Discussion

When length is changed it will take more or less time to oscillate, depending on its length and acceleration due to gravity. Therefore, the period may be varied by changing either two factors .Since acceleration due to gravity is constant on Earth; the only dependent factor is the length of the pendulum. As the length decreases the period becomes faster.

Precautions  Ensure that your eye is level with the centre of the bob when measuring length to avoid parallax error  Ensure that the pendulum swings in one plane only - avoid circular movements

Conclusions Based on the experiment done it can be concluded that a pendulum will exhibit a period that varies depending on its length, as the length decreases the period becomes faster.

EXPERIMENT #5: TITLE: MEASUREMENTS SKILL: P & D DATE: Hypothesis: The mass of the pendulum will affect the period of oscillation of the pendulum Aim: To determine the effects of mass on the period of the pendulum Problem Statement: To plan an experiment to show how the mass of the pendulum affects the period of the pendulum

Apparatus and Materials:       

20g,30g,40g,50g masses string ,ruler Compass retort stand Clamp stop watch

Procedure 1. 2. 3. 4.

Measure the length of the string to be 20cm Attach the 20g mass to the end of the 20cm string Tie the pendulum onto a clamp attached to a retort stand Place the protractor in your hand and check to ensure that the cord is at the 90◦ mark on the protractor 5. Displace the pendulum by 60◦,release and count ten oscillations, the stop watch should be started simultaneously when the mass is released 6. Repeat the procedures two through five using different masses. 7. Record your results in a table and plot a graph of mass against period

Expected Results and Explanation Length (cm) 50cm

Period 10 oscillation 14.88

One T2 Oscillation (period/10) 1.488

Angle Of displacement 60◦

Mass of the bob 20g

50cm

15.06

1.506

60◦

30g

50cm

15.11

1.511

60◦

40g

50cm

15.24

1.524

60◦

50g

Variables Manipulated  mass Responding  Time taken for oscillations to occur Control  Length of the pendulum  Number of oscillations  Displacement of the pendulum Precautions  Ensure timer is set at zero  Ensure that your eye is level with the centre of the bob when measuring length to avoid parallax error  Ensure that the pendulum swings in one plane only - avoid circular movements

EXPERIMENT #6 TITLE: MEASUREMENTS AIM: To find the center of gravity of an irregular object

THEORY: The center of gravity of a body is defined as the point of application of the gravitational force due to the earth’s attraction on it, or the point on that body where all the weight seems to act

Apparatus:  An irregular shaped object (cardboard) 

Bob

 String  Nail or small screwdriver Procedure 1. Three holes were punched as far as possible from each other, close to the edge of the irregularly shaped cardboard 2. The nail was inserted in a steady overhead board stand. 3. The object was placed over the nail and the loose end of the thread was tied over the object onto the nail. 4. A pencil was used to mark the line where the string falls on the object. 5. The above steps were repeated for the other two holes. Discussion Center of gravity of an object is where all its weight seems to act. The position on the lamina where all lines intersect is called the center of gravity. The lamina was balanced at its intersection point. Precautions  Ensure that the string swings freely across the lamina  Make sure the string come to rest before marking the positions

Conclusion The center of gravity of the lamina was determined by balancing the lamina at its intersection point

EXPERIMENT #7: Finding the weight of the meter rule TITLE: MEASUREMENTS AIM: To find the weight of a meter ruler using the principle of moments

Apparatus and Materials  Meter rule (1)  100g mass  String  Pivot Procedure 1. A string of approximately 30cm of length was tied to a 100g mass. 2. A loop was tied at the other end ,that allowed the string to be move with the 100g mass along the length of the meter rule 3. The string was placed with 100g mass at the 5cm position on the meter ruler. 4. The meter rule was balanced on the pivot.23cm from the same end measured 5cm 5. This length was recorded as l cm and the distance from the 100g mass to the pivot as d cm ,this was recorded in a suitable table 6. This procedure was repeated with the string and mass at the 10cm mark and the new values were recorded in the same table 7. This procedure was continued until the string and mass reached the 30cm mark.

Results

Precautions

Conclusion

Position of the pivot from the same end (cm)

Distance from Position of 100g the 100g mass to mass from one the pivot d (cm) end l (cm)

23.5

18.5

5

26.7

16.7

10

29.8

14.8

15

32.7

12.7

20

35.5

10.8

25

38.5

8.5

30

EXPERIMENT #8: TITLE: MEASUREMENTS AIM: To demonstrate that the extension of a spring is proportional to the applied weight as long as the elastic limit of that spring is not surpassed. Theory: Hooke’s law states that provide the elastic limit has not been exceeded the stretching force on a spring is directly proportional to the extension of that spring. The extension is the difference between the natural length of that spring and the extended length due to the stretching force.

Apparatus and materials  Meter rule (1)  100, 50, 200g masses (two or three of each preferably)  String (50 – 100cm long),  Spiral spring  Clamp  Set square Procedure 1. The ruler was repositioned so that it was right against the spring that was used in test. 2. The reference line was moved to ensure that it lines up with one of the numbers on the ruler. This mark was recorded in a table as the zero position mark. 3. The lowest mass (50g) was attached to a spring with the mouse and the extension value was recorded in table. 4. Step 5 with the other known masses was repeated and the extension values were recorded in the same table. 5. A graph was plotted of force vs extension and then determined if Hooke’s law was obeyed or not.

Results MASS (g)

MASS (kg)

Force (N) [Mass Zero Extension (kg) x 10] value (cm)

Extension (cm)

50

0.05

0.5

0

5

100

0.1

1

0

10

150

0.15

1.5

0

24

200

0.2

2

0

32

250

0.25

2.5

0

44

300

0.300

3

0

50

350

0.350

3.5

0

62

Discussion The force vs extension graph gives a straight line which shows that force is directly proportional to its extension. The gradient of the force vs extension give spring constant where spring constant is how stiff or rigid the string is. The table also shows that as the force increase the extension also increases .It was also observed that the graph obeyed Hooke’s law

Precautions

Ensure that the string does not pass it elastic limit

Conclusion Base on the experiment done Hooke’s law was verified because force vs extension reflects a straight line

EXPERIMENT #9: TITLE: Thermal Physics and Kinetic energy AIM: To find the find the specific heat capacity of a metal SKILL: Theory: The specific heat capacity is the heat required to produce a unit temperature rise (1C) in a given unit mass of the substance (1kg or 1g). So by knowing the mass of the substance and the change in temperature, the specific heat capacity of that substance can be evaluated experimentally.

Apparatus and Materials:  Measuring cylinder  Bunsen burner o  100g mass  Small polystyrene cup (3) … (8 or 12 ozs size)  Thermometer  400ml beaker (1)  Tripod stand (if using Bunsen burner)  String (10 – 30 cm long) Procedure 1. The string was tied to the 100g mass 2. Piped water was added to the 400ml beaker until it is between 1/2 to 2/3 full 3. The Bunsen burner, gauze and tripod stand was set up and the 400ml beaker was placed on top of it 4. The mass and string was placed into the 400ml beaker. The string was checked to ensure that it was just barely hanging over the side and not touching or too near the heat source.

5. The water was heated until it began to boil. Then it was allowed to boil gently for 5 minutes. This temperature was recorded in a table 6. During this 5 minute period, 60ml of pipe water was accurately measured with the measuring cylinder and transferred to each of the polystyrene cups.

7. The temperature of the water was measured in each of the cups. These temperature values were recorded in a suitable table. 8. After the 5 minute period, the mass from the boiling water with the string was removed and was gently transferred to one of the polystyrene cups.

9. The mass was moved up and down within the mass of water in the cup and the highest temperature increased on the thermometer was noted. This value was recorded in a table. 10. The mass was then returned to the boiling water and let for another 5 minutes. The mass was transferred to another polystyrene cup and the highest temperature was noted again. That value was noted in the same table. 11. The mass was then returned to the boiling water for the third time and the experiment was repeated for the final time and the temperature value was recorded in the same table Results Specific heat capacity of water = 4200 J Kg-1 C-1 Mass of water =60g Temperature of water before =33˚c Temperature of water after =39.8˚c Mass of metal =100g Temp of metal before =99 ˚c

Heat lost by metal = Heat gained by water Calculations m = is the mass of the substance (Kg) (water or 100g mass), c = specific heat capacity (J Kg-1 C-1) and T = temperature change (C)

m mass x c mass xT mass = m water x c water x T water

Mass of thermometer before = 401.1g

Mass of thermometer after =422g

Final temperature 39C Mass of water

Precautions

Conclusion

EXPERIMENT #10: Finding specific heat capacity of concrete TITLE: Thermal Physics and Kinetic energy SKILL: P & D DATE: Aim: To plan an experiment to determine the specific heat capacity of concrete THEORY: The specific heat capacity is the heat required to produce a unit temperature rise (1C) in a given unit mass of the substance (1kg or 1g). So by knowing the mass of the substance and the change in temperature, the specific heat capacity of that substance can be evaluated experimentally.

EXPERIMENT #11: The latent heat of fusion of ice TITLE: Thermal Physics and Kinetic energy AIM: To find the latent heat of fusion of ice SKILL: Theory: The latent heat of fusion is the heat required to convert unit mass of ice at 0C to the same mass of water at the same temperature. The same amount of heat is released when the process is reversed. This process occurs (in either direction) without a change in temperature. Or to say it in another way, the temperature does not increase or decrease, until the change of state is completed. The value of the latent heat of ice can be determined by completely melting small pieces of ice in a known mass of water. The heat energy required to completely change the ice to liquid would be gained from the surrounding water and so the latent heat of the ice can be deduced from the following relationship: Heat energy gained by the ice = Heat energy lost by the water ,

mice x lice + m ice x cw x Tice = mwater x cwater x Twater

Apparatus and Materials:  Measuring cylinder  Small polystyrene cup (3) … (8 or 12 ozs size)  Thermometer  Electronic balance or triple beam balance  ice Method 1. 2. 3. 4. 5. 6. 7. 8.

The Styrofoam cup was weighed on the scale The water was warmed water to 70C About 60g of water was weighed in the Styrofoam cup The initial temperature of the water was measured and recorded. About 10g of ice was added into this water The mixture was stirred until the ice was completely melted. The new temperature was recorded The Styrofoam cup with the water/ice mixture was reweighed and the value recorded. 9. The weight of the ice added to the water was deduced .

EXPERIMENT #12: Verifying Boyle’s law TITLE: Thermal Physics and Kinetic energy AIM: To verify Boyle’s Law from experimental data SKILL: A/I Theory: Boyle’s law states that the volume of a fixed mass of gas is inversely proportional to the applied pressure at a constant temperature. P  /V or vice versa and consequently P = k/V or k = PV where k is a constant 1

Apparatus and Materials:  Pressure gauge  A sealed tube with air or any other suitable gas Method: 1. The default value on the system at the given temperature was noted and recorded in the table. 2. The pressure was increased by defined amounts e.g. 20kPa or 20 atm on the system and the corresponding change in volume noted. 3. The new values were recorded in the same table. 4. This was repeated 5 more times, each time recording the pressure and volume values in the table. Results Pressure

Volume (ml)

V

15.8 17.4 20.0 22.2 23.8

32.6 29.6 25.7 23.2 21.6

1.63 0.57 0.050 0.045 0.42

Discussion

Precautions

Conclusion

EXPERIMENT #13: Verifying Charles’s law TITLE: Thermal Physics and Kinetic energy AIM: To verify Charles’s law by experimental methods SKILL: O/R/R Theory: Charles’s law states that the volume of a fixed mass of gas is directly proportional to the temperature at a given pressure. V  T and consequently V = kT or k = V/T where k is a constant

Apparatus and Materials:  Volume gauge  A sealed tube with air or any other suitable gas Method: 1. The default pressure value on the system was noted and recorded in the table 2. The pressure was increased by defined amounts e.g. 10 or 20 C atm on the system and the corresponding change in volume was noted. 3. The new values were recorded in the same table. 4. This was repeated 5 – 6 more times, each time recording the temperature and volume values in the table.

Results Pressure

Volume

286.5 296 307 320 340

24.95 26.00 26.78 27.91 29.166

Precautions

Conclusion

EXPERIMENT #14: Investigating the relationship between incident light and reflection TITLE: Waves and Light AIM: To investigate the relationship between incident light and reflection SKILL: M/M Theory: Reflection occurs when a wave hits a boundary and goes back into the medium without crossing the boundary. The laws of reflection states that: 1. The angle of incidence is equal to the angle of reflection 2. The incident ray, the reflected ray and the normal all lay in the same plane 3. When reflection occurs the wavelength of that ray remains unchanged

Apparatus and Materials:  Plane mirror  Common pins  Sharp pencil  Cardboard sheet (8” x 11”) or bigger  Plain paper  Protractor  Small ruler (preferably clear plastic) Method: 1.

A protractor and ruler; were used to draw a horizontal line on the lower third of the plain paper. The paper was placed in the landscape position.

2.

The protractor and pencil were used to draw a normal line in the center of the horizontal line (broken lines). A line was drawn 10 from the normal Two pins were placed at different positions along this line. The mirror was placed in line with the horizontal line so that the normal line was in the center of the mirror On the other side of the normal line, using the reflections in the mirror, the two other pins were aligned so that they appeared as one in the reflection. The pins were removed and a line was drawn through the pin holes. This represented the reflected ray.

3. 4. 5. 6. 7.

8. 9.

The angle of the reflected ray was measured and both the incident and reflected ray angles were recorded in a table The procedure was repeated six more times each time increasing the angle by 10 and recording the results in the same table.

EXPERIMENT #15: Finding focal length of a convex lens TITLE: Waves and Light AIM: To determine the focal length of a convex lens SKILL: M/M Theory: A convex lens is thicker in the middle than the edges. It has the ability to bring incident parallel rays into a single focal point. This focal point can be determined from experiment.

Apparatus and Materials:  Convex lens  Convex lens holder  Light source  White screen  Illuminated object (with a pin or a small mesh in the centre)  Meter ruler  Small ruler (preferably clear plastic) Method: 1. 2. 3. 4. 5. 6.

A protractor and ruler; were used to draw a horizontal line on the lower third of the plain paper. The paper was placed in landscape position. The apparatus was set up in a similar manner to the diagram. The image on the screen was adjusted until a sharp image was seen. The distance of the illuminated object from the lens was recorded as u and the distance of the image on the screen from the lens was recorded as v in a table The distance u was decreased by 5cm and the screen was re-adjusted until the image was again sharp. The v value was re- measured and both u and v were recorded in the table This was repeated for four to five more times and the values were recorded in the table. Using the equation: 1/u + 1/v = 1/f, the value of f was determined from values of u and v in the table.

Results ..u (cm)

v (cm)

1/u (cm-1)

1/v (cm-1)

34

31

1/34

1/31

26

Calculations

Discussion

Precautions

Conclusion

32

1/26

1/32

1/f (cm- f (cm) 1 ) 65/1054 16.2 58/832

14.3

EXPERIMENT #16: Length of a wire and resistance TITLE: Electricity and Magnetism AIM: Investigating the relationship between change in the length of a wire and resistance Theory: The resistance of a wire is directly proportional to the length of a wire as shown by the relationship RL/A. with A being the cross – sectional area of the wire. (R=kL/A), k = resistivity constant

Apparatus and Materials:

 Resistance meter Method: 1. The material to be assessed (Copper, Aluminum etc) was chosen. 2. The thickness of the material … 0.25cm was selected 3. The starting length of the wire and the corresponding resistance for this length was selected. These values were recorded in a table. 4. The length was increased by a steady value e.g. 10cm and the corresponding change of resistance recorded in the same table. Results

R=Resistivity A

0.17 Copper per Cm

Length (cm)

Resistance ()

2.2 4 5.4 7.6 10

1.56 2.43 3.2 5.37 7.07

EXPERIMENT #17: Thickness of a wire and resistance TITLE: Electricity and Magnetism AIM: To investigate the relationship between change in the thickness of a wire and resistance SKILL: P & D DATE: Theory: The resistance of a wire is inversely proportional to the area of a wire as shown by the relationship

EXPERIMENT #18: Voltage characteristic of a Lamp TITLE: Electricity and Magnetism DATE: AIM: To Investigate the voltage characteristic of a lamp Theory: The voltage in a circuit relates to the current and the resistance by the relationship V = I.R, where I = the current flowing through the lamp and R = the resistance of the lamp

Apparatus and Materials:  Voltmeter  Power supply etc Method: 1. A circuit was set up similar to the one below. The current flowing was of a given value but the resistance could be varied by the variable resistor 2. The resistance was increased incrementally for about 5 different values and the corresponding changes in voltage across the resistor in the circuit was noted. 3. These values were recorded in a suitable table 4. The relationship of V to R when I is constant was deduced.

EXPERIMENT #19: Effect of distance (from the detector) on the transmission of beta radiation TITLE: Physics of the atom AIM: To find the effect of distance (from the detector) on the transmission of beta radiation DATE: Skill: Theory: Beta radiation is one of three types of particles emitted from radioactive sources. It is the second most penetrating type of radiation (after gamma) and is absorbed fairly rapidly by air molecules but is still able to travel several cm in air from its source. In this experiment the travel distance of these particles will be assessed.

Apparatus and Materials:  Geiger counter  Beta radiation source etc Method: 1. The level of background radiation was determined before placing the source in front of the detector. 2. The counter was reset and the experiment was repeated three times to get an average count per second for the background radiation. 3. The results were recorded in a suitable table 4. The beta radiation source was placed 30cm from the detector. The counter was reset and used to determine the count rate for the next 10 seconds. 5. This was repeated twice or thrice for this distance and the results recorded in the table. 6. The distance was moved to 25cm and step 5 repeated. 7. The distance was decreased by 5cm until a distance of 10cm was reached, the results were recorded in the table. 8. A graph was plotted showing the average count rate vs distance (x axis) 9. A reasonable discussion and conclusion were written

Source

Distance (cm)

Count Duration (sec)

Count

Average Count Rate

30

10039

25

13876

20

1999

15

30475

10

49821

EXPERIMENT #20: Effect of shielding materials on the transmission of beta radiation TITLE: Physics of the atom AIM: Effect of shielding materials on the transmission of beta radiation SKILL: P & D DATE: Theory: Materials can absorb beta radiation by varying degrees. In some cases, these materials are quite permeable and very little absorption takes place. In other cases, the materials are highly absorptive and very few beta particles can penetrate the material. Plan and design your experiment to show how you would assess this.

Apparatus and Materials: (YOU DETERMINE THE MATERIALS NEEDED FOR THIS EXPERIMENT)

METHOD: (YOU DETERMINE THIS)