precautions physics experiments

salman85

would any one be kind enough to tell 2 precautions for

boyle
a vs F
convex/concave lenses/mirriors
heat of fusion / vapourisation

i know some i just wana confirm like

boyle open the tap slowley and wait 2 minutes to keep constant temprature

a vs f level air track, and only change the weight from one place to other
concave/convex parallax, error can occur when judging sharpest image
heat of fusion crush dry ice (dont know 2nd)
vaporisation use dry steam comming from steam trap (dont know 2nd)

Fringe

For the heat ones, insulate all containers.

Peleus

salman85 wrote: »

a vs f level air track, and only change the weight from one place to other

I think there is supposed to be a friction compensating slope in that experiment. i might be wrong.

salman85 wrote: »

concave/convex parallax, error can occur when judging sharpest image

when measuring image/object distance, measure from the CENTER of the lens.

salman85 wrote: »

heat of fusion crush dry ice (dont know 2nd)

that is two.
Crush ice so that it melts uniformly
Dry Ice so that there is no water in the experiment that you havent accounted for in you calculations.

Zonda999

salman85 wrote: »

would any one be kind enough to tell 2 precautions for

boyle

Everytime you let off pressure, wait a minute or two sbefore you read the new pressure off the scale
Cant think of a second for that one

starkinter

Zonda999 wrote: »

Everytime you let off pressure, wait a minute or two sbefore you read the new pressure off the scale
Cant think of a second for that one

Do not allow pressure to become too high because Boyle's Law does not hold at very high pressures or very low temperatures.

benzwOw

quick question:
why glycerol used instead of water in experiments such as "To investigate the variation of the resistance of a metallic conductor with temperature"

raah!

It heats up slower, so there is less difference between the liquid in which the coil is and the coil.

Whe whe whe, in my book, for boyle's it has "be careful not to get oil on your clothes as you are releasing pressure"

Stin

ha, yeah mine has that clothes thing aswell
good luck in your physics test tomorrow raah!:)

mike-gunners

salman85 wrote: »

would any one be kind enough to tell 2 precautions for

boyle
a vs F
convex/concave lenses/mirriors
heat of fusion / vapourisation

i know some i just wana confirm like

boyle open the tap slowley and wait 2 minutes to keep constant temprature

a vs f level air track, and only change the weight from one place to other
concave/convex parallax, error can occur when judging sharpest image
heat of fusion crush dry ice (dont know 2nd)
vaporisation use dry steam comming from steam trap (dont know 2nd)

precautions:
1.boyle's law:
(i) wait a few minutes before reading the volume of air in order to let the air settle at room temperature.
(ii) if the pressure gauge reads atmospheric pressure(1.01 X 10^5) when valve is open, then take the pressure reading directly from the gauge
(iii) if the gauge reads 0 pressure when the valve is opened, then atmospheric pressure must be added to the pressure obtained.

2. a ><> F
(i) Compensate for friction by raising one end of the runway so that, with a slight push, the trolley moves with a constant velocity.
(ii) use a frictionless pulley.
(iii) dust the runway and the wheels of the trolley

3.Fusion of ice
(i) warm water is used for two reasons: first reason is that it melts the ice more quickly.the second reason is that it can melt a large amount of ice, thus causing a great change in temperature and reducing percentage error.
(ii) use a low specific heat capacity thermometer when measuring the temperature to ensure less heat loss to the surroundings.
(iii) use lagging/insulation in the beaker to ensure minimum heat loss.

raah!

Stin wrote: »

ha, yeah mine has that clothes thing aswell
good luck in your physics test tomorrow raah!:)

I Stin that.