O/A Level Physics Practical Precautions
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Hi everyone.
As you know, physics practical is coming... Usually at the end of practicals, there will be a question on what precautions you are supposed to take.... I had such a list from my teacher in sec school on common questions and answers for precautions... But that was so long ago... and I lost it...
Now, I would like to compile another list for everyone to download and use. Would like to seek everyone's help in contributing the questions (and answers) if possible. What is to be done is to state the type of experiment (Mechanics, Thermodynamics, Waves, Electromagnetism)
Example:
Electromagnetism
About connecting circuits:
1) Make sure all connections are tightened and secured to minimize contact resistanceMechanics
About measurements
1) Read directly above the ruler to prevent/minimise parallax errorThanks everyone for the help.
Regards,
Eagle
Owner of Strategic Tuition -
No one cares to share/help?
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forgot already =xx
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Rulers to be kept horizontal using spirit level
Timing is started only when oscillations are steady.
Ensure metre rule used to measure height is vertical by using a set square.
Height is measure using increasing and decreasing values of L.
When measuring height, ensure that the vertical ruler is placed close to the end of clamped ruler, reading at eye level.
Ensure height is measured at the same point.
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Repeat timing for each value of R to reduce random error.
Check the wire connections to ensure that there are no loose connections in the circuit.
The reading on the multimeter is changing rapidly, hence do a few trials before taking the actual measurements.
Check that the reading on voltmeter is zero before closing the switch.
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Originally posted by starmoonsun:
Repeat timing for each value of R to reduce random error.
Should be repeat around 3 timings for n oscillations to obtain an average value of T (period), where n should be of a suitable value, usually 20.
Make small angle oscillations to minimize effect of air resistance and to keep retort stand steady.
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Thanks everyone
Keep the contributions coming...
I will edit and compile them when I find the time
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bump
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Oh no!!! 2 more days to practical )))): any tips?
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tmr is practical !
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Ask mypillowtalk post my msn conversation with him here.Revise with him alot of things.
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Constructing a table.
Always construct with a heading magnitude+ a state symbol.
If your heading doesnt have symbols, always make sure your readings have a symbol.
Example, you write a value of 5.
5 what?
5 monkeys? 5cm? or 5 metres.Marks will be deducted.
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Accuracy.
burette: 0.1cm3
pipette: 0.1cm3
difference between burette and pipette.
burette: measures readings of up to 0.1cm3, like 23.5cm3 ect.
pipette: measures SET volumes - 25cm3, 10cm3, 15cm3.
Measuring cylinder: 1cm3 accuracy - dont be a blur cock and write 1.0cm3 - marks will be deducted for in accurate accuracy.
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Measuring lengths:
check for zero errors.
you can do so by closing the jaws of the apparatus, and look at the if the "zeros" of the 2 scales are at the same point.
if they are not, then - or + the readings.
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Time:
O level practicals require you to measure up to the nearest second. - from the text book.
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anymore? \: more on chem if can pls
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anyone back?
im from 1st shift
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holy shit chem quite hard!
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Originally posted by Maith:
holy shit chem quite hard!
quite hard? wtf it is really wtf.
never expect the last question to be just conclusion. made me study all the shit like gas collection. the copper colours.planning experiment thingy.
and the error for physics, according to my teacher, is the ruler must be constantly horizontal.
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Originally posted by deteq:
quite hard? wtf it is really wtf.
never expect the last question to be just conclusion. made me study all the shit like gas collection. the copper colours.planning experiment thingy.
and the error for physics, according to my teacher, is the ruler must be constantly horizontal.
wtf! lolololol then my error qn sure wrong liao. I put parallex error thingy..);
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mine i put parallex and zero error. both are wrong
chem the observation part too high marks liao i also dont know what to write. frankly, if i pass my practical i think it will be because moderation.
bo bian liao. must pia for theory paper le.
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die liao lar
i say do more test then take average for phy
chem i tink is test for cloride and iodide
cos put starch turn blue then black
then white ppt cnnt dissolve
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last part is ammonia gas which i failed to notice.
anyway i still dont understand.why bother testing for anything if they at the start already tell us solid T is only 3 elements Br,K and O.
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Originally posted by deteq:
last part is ammonia gas which i failed to notice.
anyway i still dont understand.why bother testing for anything if they at the start already tell us solid T is only 3 elements Br,K and O.
i think they wanted us to find out what ppt is produced and what gas is present i guess..\:
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omg.. i tot i saw zinc !! and when i was washing the test tube, i saw white fume coming out. its just crap~~