Physic junior cert invesigation 2006

Absolute Zero

Hi , seeing as another guy posted about help on the chemistry part of this investigation ( which gave a lot of help, thanks to a link some one pointed out ) i was wondering if any one knows any links or can help me with the physic part which is Investigate the relationship between the temperature of a rubber squash ball and the height to which it bounces. We will be starting the investigation on monday but out teacher said if any one can come up with some information about this by useing internet , library etc, i would be grateful if any one can help. Thanks Az

ApeXaviour

How high it bounces has to do with it's elasticity (how elastic it is). So elastic bands can be a good alternative display of basically the same principal:
http://www.physlink.com/Education/AskExperts/ae573.cfm
(btw "softer, easier to stretch" means it's becoming less elastic, ie if you pull it apart, or in a rubber ball's case push it together, there's less of a return force)

Here's another website that seem to have done the very experiment you want:
http://galileo.phys.virginia.edu/Education/outreach/8thgradesol/EffectofTemperature.htm

Good google keywords to find more: "elasticity, bounce, temperature"

Sciaran

nice one, your sites for the science coursework proved pefect for the job at hand
keep it up!!

Sciaran

heyy!! just wondering if u know why exactly one needs two squash balls in the physics exp. I take it you read about that happy and sad ball you see, but isn't ok to use one?

ApeXaviour

Sciaran wrote:

heyy!! just wondering if u know why exactly one needs two squash balls in the physics exp. I take it you read about that happy and sad ball you see, but isn't ok to use one?

Well its use is to demonstrate that elasticity isn't solely based on the temperature of the material but the type of material too. If this is not part of your investigation then it is ok to negate it.

So two regular squash balls shown to have similar bounce heights when at room temperature. One placed in a freezer, one in an oven (or on a radiator? Don't want to melt it). Afterwards two balls at different temperatures dropped from same height. Observe difference in bounce height.

Just as an aside: it's best not to drop balls from your hands as this can taint the experiment. Better to roll gently off a desk or from a clamp/trapdoor placed at height.

Geg124

Im not doing this experiment but for my mates. Can you read the height the ball bounces to accuratly?? My mates cant so they are using the video on their mobile to judge it and they have the ball bouncing in front of a metre stick. I think this would work but how did you do it??

ApeXaviour

Geg124 wrote:

Im not doing this experiment but for my mates. Can you read the height the ball bounces to accuratly?? My mates cant so they are using the video on their mobile to judge it and they have the ball bouncing in front of a metre stick. I think this would work but how did you do it??

I didn't do it, the junior cert seems to have changed somewhat since I did it in '99. I'm just helping yis out to procrastinate from studyin for college exams which I'm currently in the midst of

For a demonstration it's enough to see that they are bouncing different heights. But for an experiment you'd need to measure the height. Your mates' suggestion sounds promising. A camera capable of freeze-frame playback (put the vid on the computer and press pause?) and with enough resolution to read the metre stick would be more than accurate enough for your purposes I'd imagine. I'm sure there are many novel ways of measuring it. If you had access to a pen laser for instance, you could drop the ball from the same position multiple times beside a wall. Each time you could adjust the height of the laser (pointing against the wall, in the path of the ball) downwards until it the light on the wall becomes momentarily obscured by the rebounding ball. Then measure the height the laser dot is on the wall when that happens. Do it a couple times for good measure.

Geg124

Thanks for that advice mate but ill think ill tell them to stick with the camera on their phone because it seems easier and also because we wouldnt be able to get a laser pen.

Thanks for your help thought

Killaqueen!!!

wow great sites thanks! we're gonna 'brainstorm' in class on Monday so this stuff is great! I hope no one else in my class finds that great site :P hehehe

whats with the happy/sad ball thing..? I'll read it properly later! thanks!

Killaqueen!!!

I didn't realise I have to do the experiment TOMORROW! I'm so screwed. I've googled and haven't really found anything.

I was wondering, also, how to measure the height accurately. Other than judging solely by your own eyes, there's not much you can do. The video camera option wouldn't be great (as I see it) - even worse if it's on a mobile phone, as most phones don't have good quality video recorders. Mine seems not to play very smoothly, rather to 'jump' at points.

Professional video camera equipment would be ideal, and you could put it in slo mo mode, or put it on your computer and pause it. But this again, isn't a choice for me. (I don't have a video camera, and our experiment is pretty much restricted to the lab)

So what other options are there? I don't see how the laser thing would work How do you get the laser to point exactly where the ball has bonced up to?

This is a very messy investigation..I preferred the Chemistry one. There's so many things that could go wrong, that could lose accuracy. Most importantly, the temperature. After taking the ball out of the boiling water (using tongs) and drying it (water could effect the experiment), you could have lost a few degrees Celcius in heat before you even drop the ball at the top of a metre stick. This would not matter so much, but you have to GRAPH it..pretty accurately. I'm thinking it will be a proportional graph?

arrgh...

Delphi91

Don't get too deep into the investigations.

Measuring the height is not all that difficult - use a tape measure attached to a desk, etc. You won't be expected to have answers which are accurate to 1-2 decimal places.

Forget about the laser idea. Its too complicated and is unneccesary.

Remember that these investigations have to be capable of being done at home by students with no access to lasers, etc.

At the end of the day, all that is being looked for is some evidence of a relationship (if any) between the temp and the height of the bounce.

As for an accurate graph, where does it say that? Why not produce a bar chart? That would show the relationship and wouldn't need a high degree of accuracy.

As for the temp of the ball dropping due to drying it, etc, ignore it. You'll never be able to quantify that as you can't measure the temp of the ball in the first place!! Unless you bore a hole in the ball and stick a thermometer into it, you'll always have to "assume" that the temp of the ball is the same as the temp of the hot water that you used to heat it up. And how accurate is that assumption?

BTW, I am a Junior Cert Science teacher, so I do know what's involved and required.

Killaqueen!!!

wow thanks a lot for your help! The experiment side didn't go TOO bad. I've just figured out there's no way of recording the EXACT relationship between temperature and height (due to many problems..some I listed in my previous post) so the best thing to do is just the basic experiment. Get a metre stick, and judge by eye what height it bounced to. Pretty much simple as that.

As for showing your results. Our teacher said a graph is expected but your idea of a bar chart seems good too. I did a rough graph and it was pretty good. It went up at a constant height (i.e in a straight line) for a good few of the temperatures and then it sort of rounded off. But that's what is supposed to happen I think, because it gets to a temperature where it doesn't affect the ball height as such..and it sort of levels off.

A 'messy' experiment..but pretty easy!

Thanks a lot to everyone who helped in this thread! If you have anymore sites post em, cos I have to do my write up (which is the hardest part I think!) in a ouple of days!

See ya!

xXXshell(",)x X

im writin up d squash ball experiment 2mro...............(eek)i duno wat im spose 2 b doin nd all the gang in my friend's skool hav dis big long complicated write up but im clueless yee sound lyk ye know wat yer on bout?i mean lyk wer ment to write lyk 7pgs bout bouncin a ball............!?!

Delphi91

xXXshell(",)x X wrote:

im writin up d squash ball experiment 2mro...............(eek)i duno wat im spose 2 b doin nd all the gang in my friend's skool hav dis big long complicated write up but im clueless yee sound lyk ye know wat yer on bout?i mean lyk wer ment to write lyk 7pgs bout bouncin a ball............!?!

I'd forget about doing the write-up and learn to spell first, because if you write that report like you've written your post, it will be unreadable!:rolleyes:

Killaqueen!!!

Yeah I hate the write-up's too! Can anyone give me a basic passage on the Kinetic Theory (as relative to this experiment) as our teacher gave us a hint that it'd be good to write a bit about that in the Introduction