In Homi Bhabha Practical Exam (Level 2) — For each experiment, you have to carry out the activities and then answer the given questions. However, even though the name is ‘practical exam’ your score mainly depends upon how nicely you write the answers!
And so, here are some tips to help you improve your score –
1. Final answer should be neat and clear.
No cancellation and over-writing in final answer. Digits and decimal points should be very clear.
If you have to change the answer — cancel it completely, leave some space and rewrite the correct answer.
2. UNITS are a MUST
Answers without units carry ZERO marks and a very bad impression!
(The same answers have got zero marks in the first case!)
3. Show formulas and calculations.
If you have used some formula or principle, DO mention it. If you have done some calculations, show them.
Write a couple of steps that will show how you arrived at the final answer. This will tell the examiner that you have indeed found the answer yourself and not copied it from someone else.
4. Measure Accurately, not approximately
While taking the reading, do NOT round off the answer. All measurements should be as accurate as the given instrument allows.
E.g. If the length of the object you have measured is 6.2 cm, you should not round it off to 6 cm. Later if the calculation becomes difficult, at that point you can round off the values and write approximate answer at the end.
E.g. You may write:
Length = 6.2 cm
Breadth = 2.1 cm
Height = 1.1 cm
Volume = L x B x H
= 6.2 cm x 2.1 cm x 1.1 cm
= (approximately) 6 x 2 x 1
= 12 cu cm
5. Check the least count of the instrument
While using measuring cylinder, beaker, spring balance, etc. students often forget to check the least count.
E.g. What reading does this spring balance show?
Students often write the above reading as “410 gm”. But if you observe carefully, the least count is 20 gm – So the reading is actually 420 gm.
6. Write ALL the answers
In Homi Bhabha practical exam some questions are based on the activities of the experiment performed while some questions are based on the theory which you have studied earlier. Even though such theory questions do not depend upon the experiment, they do carry marks.
So do ensure that you answer all the questions.
7. Write scientific answers, not essays!
For descriptive questions like – ‘Explain your method / reason’ or ‘why does this happen?’ – you are expected to write short and scientific answers.
Underline the scientific principle used, if any. Do NOT write long essays like this –
Your answer should be short and logical. English language skills are not important. You can make shortcuts to save time. A good quality answer should have scientific terms which show your understanding.
Do mention the scientific principles involved in the experiment (even if not asked) – e.g. repulsion of magnets, neutralization of acid-base, refraction of light, etc.
8. Read the entire experiment carefully and plan what you are going to do.
A sample experiment:
Take a pinch of Baking Soda and Citric acid in a crucible. Add a few drops of water. What do you observe? Hold a moist blue litmus paper over the crucible. Write your observations and explain with reason.
Most students observe that bubbles start coming out when water is added. They keep watching the bubbles till they stop. Then they read the next line! But now the reaction is over, so it is too late to hold the litmus! So they have to clean the crucible and do the entire experiment all over again.
Secondly they overlook the word ‘moist’ and hold the dry litmus as it is. So it does not react with the emerging gas. And then they dip the litmus into the liquid instead of holding it ‘over the crucible’ – so they end up testing the liquid instead of the gas!
So read carefully.
9. Use Common-sense
E.g. 1 – The sample shown below was kept and the question was – “Which part of this plant is reduced?”
A student said that he could not identify the plant and so he did not answer the question.
But actually the name of the plant was not asked at all. Now the leaves and roots are very clearly visible. So they are definitely not reduced. So ‘stem’ is the only one that must be reduced.
E.g. 2 – A steel spoon and scale was given and the question was – “Hold the spoon at approximately 30 cm from your eye and observe.
One student got the spoon but not the scale. He immediately told the supervisor and a big search was organised for the scale. Finally he got the scale but could not finish writing the answers.
Now, the 30 cm value is anyway approximate. Nobody is going to put one end of the scale in the eye and the spoon exactly at the other end. So what you could do is simply use your regular scale twice to get approximately 30 cm distance.
Remember: Our intention is to DO the experiment and NOT to prove that it is impossible to do it!
E.g. 3 – A small stone was given. Its density was also given. It was asked to find its volume using overflow vessel and then calculate its mass.
A student measured the volume correctly but made some mistake in the calculation and got final Mass = 4 kg.
Now you should have some idea how heavy 4 kg is! And just holding the stone will tell you that it certainly can’t weigh so much.
Similarly, you should have some idea how long is 1 cm, 1 metre, 1 foot, 1 inch, etc.
10. Ignore others around you
Focus only on your task and answers. Don’t bother to see what others are doing.
If someone asks for help in completing their task, bringing / holding something for them, etc. just refuse politely and continue your work.
If the supervisor writes some remark / symbol/ letter on your answer sheet, just ignore it.
If you meet earlier batch students who have completed their exam, don’t ask them “What was there?”, “What was asked?”…
And finally, don’t forget to carry writing material, scale, napkin, and ADMIT CARD. Reach the venue 15-20 minutes before the given time.
ALL the BEST and Enjoy your Practicals!!
Rahul Dilip Ogale
Udita Rahul Ogale