Structure for Writing Sba Labs for Physics

INSTRUCTIONS PHYSICS

FOR

WRITING

SBA

LABS

FOR

Your report must be concise and logically presented. GOOD ENGLISH GRAMMAR, SPELLING and NEATNESS are necessities. If you cannot write legibly, then print your work in block letters. Remember your teacher cannot be expected to give credit for work which cannot be read. Further your report must be written in past tense and passive voice. ABSOLUTELY NO USE OF CORRECTING FLUID/ TIPEX/WIPEOUT. Instead cross out with a single stroke or use a piece of paper of exactly the same type and stick it over the area that needs to be covered. Your labs books shall be properly covered and your name and subject and class must be place on the front cover. Covering should be plain with no print. All labs should have: 1.

A lab number

2.

Date of commencement of the particular lab, in the case of planning and designing labs, date it was given

3. TITLE

4.

AIM – the purpose of the lab

5.

APPARATUS/ MATERIALS – List of all the materials and equipment to be used in carrying out the experiment

6.

DIAGRAM – drawing of the set up of the lab •

Should be done using a RULER and pencil, NO SHADING

• Should be properly labelled • Labels, should be to one end of the page

• All labels should either be in all small letters or all capitals •

All diagram should have a TITLE IN PENCIL AND UNDERLINED

• NO COLOURED INK, PENS, CRAYONS ETC, SHOULD BE PART OF THE DIAGRAM OR LABELS

7.

PROCEDURE - A description of the procedure (method) used. Always write what you did. • Should be in point form. • Should be in PASSIVE VOICE, that is there should be no use of the words I, We, They, Us etc

Eg: COMMAND VOICE : Measure the length of the stool PAST TENSE: I measured the length of the stool PASSIVE VOICE: The length of the stool was measured.

In planning and designing labs, procedure can be written in command voice or passive voice.

8.

OBSERVATION AND RESULTS – the OUTCOME of procedures carried should be presented, without repeating the procedural details. You may discover deviations from ‘expected’ results occur more often than you would prefer. Nevertheless, be honest in what you record.

•

Most results should be placed in table form or using graphs .

• All tables should have proper heading and units •

All tables should have an underlined title eg. Pg 27 – TEXT BOOK –Physics for CXC

• For graphs refer to page 27 – 32 – TEXT BOOK – Physics for CXC

9.

Calculations – Often, calculations involving data (i.e data analysis) are required. Show ALL calculations. •

If the same formula was used more than once, only show one example of the calculation done.

10. Discussion

/Interpretation – Try to present the relationships and generalisations shown by the results. Bear in mind that a good discussion, you ‘discuss’; not simply restate the results and observations. Remember your results do not have to agree with expected results. Show how your results agree or disagree with those expected. REMEMBER TO KEEP THE TENSE IN PASSIVE VOICE AND PAST TENSE.

11. Sources

of Error: State all the possible factors that may affect your experiment

12. Precautions:

What methods did you take to reduce or eliminate those errors stated in your sources of error.

13. Conclusion:

Refer back to the aim of the experiment when drawing conclusion (s).

14. Answers to follow up questions should be placed in your discussion.

Before you submit each report.

1. Ensure that a copy of your report is placed in your notebook, you will be tested on work done in the lab as well as work done in the class. 2. READ it at least once to check for errors and tidiness. You might be surprised that your report is full of errors. 3.

Number all pages, make sure your name is on your SBA book

4. Stable or otherwise secure all loose pages (including tables and graphs) together in sequence.

Example of instructions given for lab exercise Date: Title: Properties of Matter Aim: To determine the relative density of alcohol, oil and salt water Introduction: Relative density is used to determine if a material is denser than water. In the following exercise you will attempt to find the relative density of different materials. Materials Beakers, Oil, Alcohol, Salt solution, Electronic balance scale Method: 1. Find the mass of empty beaker using electronic balance scale 2.

Find mass of beaker with 25mm3 of water

3. Find mass of water. Mass of liquid = mass of liquid and beaker – mass of empty beaker 4. Repeat steps 2 and 3 for the same volume of oil, alcohol and salt water 5. Find the relative density of all four substances 6.

Record all your observations

Questions: What is relative density? How can the relative density of a substance be useful? Example of a lab report: LAB # 1 Date: 12th November, 2008 TITLE: Properties of Matter AIM: To determine the relative density of alcohol, oil and salt water APPARATUS/MATERIALS: 5 beakers, 1 electronic balance scale, salt water solution, oil, rubbing alcohol DIAGRAM:

PROCEDURE: 1. The mass of an empty beaker was found and recorded using an electronic balance scale 2.

A second beaker containing 25mm3 of water was then placed on the electronic balance scale and the mass of the beaker and water was then recorded.

3. The mass of water was then calculated 4. Steps 2 and 3 were then repeated for the same volume of oil, alcohol and salt water 5.

The relative density of all four substances was then found using the formula:

OBSERVATION/RESULTS: Table Showing Mass of Liquid and Relative Density LIQUID USED

Mass of Liquid and Beaker M/ g Water 56.23 Oil 54.14 Alcohol 54.01 Salt water 57.14 Mass of beaker: 31.99g

Mass of liquid Ml/g 24.24 24.13 22.02 25.15

Relative Density 1.00 0.99 0.91 1.04

CALCULATIONS:

Mass of liquid and beaker – mass of beaker = mass of liquid 56.23 g – 31.99g = 24.24g

DISCUSSION: Relative density measures the number of times a substance is denser than water. Relative density is a ratio; it is a dimensionless quantity, which means it has no units. If the relative density of a substance is less than one, then that substance will float on the surface of the water and likewise, if the relative density is greater than one, then the substance will sink when place in water. The theoretical relative density of water is 0.8 but in this is experiment it was found to be 0.91. This can be attributed to the fact that the alcohol used was not pure; rubbing alcohol contains other chemicals which may have altered its density.

Sources of Error: Systematic Error Random Error

Precautions: Electronic balance scale was zeroed before any readings were taken Electronic balance scale was placed on a flat- levelled surface to prevent systematic error Readings were repeated to reduce random error

CONCLUSION: The relative density of oil, alcohol and salt water was found to 0.99, 0.91 and 1.04 respectively.

Please note, in Planning and Designing labs, instructions are not given. You will have to design the investigation and plan the most sensible sequence of steps for carrying it out.

A situation will be given. You are expected to: Develop an appropriate hypothesis which will be place after the title Hypothesis: a scientific theory to be tested based on the problem. Procedure can be written in command voice or passive voice

You are expected to clearly identify the different variables

• Manipulated variable – the variable that will be changed in order to obtain different readings • Controlled variable – the variable that remains constant through out the experiment • Responding variable – the variable that is measured after the manipulated variable has been altered. This can be place in your discussion. REMEMBER everything else is the same as in the normal lab write up