Tips on carrying out galileo's theory of falling objects in a class environment?

M

moilnir

New member
A tennis ball will fall rather fast. I got my pupils to use plastic cups, these fall slower because there is more friction with the air.
We found a suitable height (7m) on the stairs and dropped them. Using masses from the lab, which we put inside the cups held with Bluetak, we obtained a range of masses.
Timing we used the stop clock on their mobile phones, which is more accurate than the school stop clocks!
The person dropping started the clock, their partner shouted "now" when the cup landed. This did introduce a very slight error - which they mentioned in their report.
We did 3 replications per mass. Any cups that drifted off course or collided with something we ignored.

Then we did "Average speed" = 7m/time (s)

Plotted average speed against mass and, allowing for the crudity of the experiment, got a straight line showing mass did not affect falling speed.

ps All cups were same shape, volume, surface area. The height was fixed so this was, as we say, "a fair test"

GOOD LUCK!
 
my lab partner and I have to carry out galileo's theory of falling objects as a physics experiment in class.

We need to get a safe way of carrying out this experiment so that we can receive permission.

I was thinking of dropping maybe a tennis balls on different levels of the school stairs.
Can you think of or recommend any ways in which we could get the timing of the release of the objects perfectly ?

I was thinking maybe a stop watch.

any useful suggestions would be highly appreciated.


ty
 
Galileo "fooled" gravity by rolling objects from rest down inclined planes and timing their descent (with his pulse!). The advantage of this method (the inclined plane, not the pulse timing method) is that it slows the objects (balls?) down enough that the timing may be made accurately. A stop watch is a good idea. A photo gate or high-speed camera are very good ideas, but you may not have access to either of these. I hope this helps you, good luck!
 
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