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### It's About Time C

Posted: June 9th, 2009, 9:08 pm
Discussion for It's About Time C.

### Re: It's About Time C

Posted: August 3rd, 2009, 6:50 pm
I wish I was still in SciOly to continue on with this event. Oh well.

So does anybody know what the planned changes to the rules are going to be? Are they going to change the size limit? Narrow down how much can be on the test?

### Re: It's About Time C

Posted: August 4th, 2009, 6:05 am
I've always wondered if you can perfect water as the timing device. I briefly tried it last year, and gave up to do other events when it failed. I wonder if I have the time and the mind to experiment with that again this year.

### Re: It's About Time C

Posted: August 4th, 2009, 10:52 am
scienceolympiadist wrote:I've always wondered if you can perfect water as the timing device. I briefly tried it last year, and gave up to do other events when it failed. I wonder if I have the time and the mind to experiment with that again this year.
I also tinkered with water clocks at the beginning of the season. Keeping the water pressure constant was pretty easy to fix, but what I was stumped on was how to account for variations in barometric pressure and other natural variations. I ended up switching to pendulums because they are a lot cleaner and simpler. Of course these same problems occur with pendulums but it seems to have less of an effect. We ended up with a pendulum clock that was almost perfect, only fluctuating with human error. This year, I am going to try to eliminate the human error. Easier said than done.

### Re: It's About Time C

Posted: August 4th, 2009, 1:59 pm
For pendulum...wouldn't the amplitude damper signifcantly over time?

### Re: It's About Time C

Posted: August 5th, 2009, 1:42 pm
scienceolympiadist wrote:For pendulum...wouldn't the amplitude damper signifcantly over time?
Yes, but that's one of the great properties of pendulums. The period of the pendulum is not dictated by the amplitude. So basically, even as the amplitude lessens the period will stay the same as long as you keep the length of the pendulum and the gravity constant.

### Re: It's About Time C

Posted: August 5th, 2009, 7:19 pm
Right, T = 2(pi) * (L/g)^(1/2). But eventually, the amplitude becomes so small that it's hard to discern an oscillation. Then, it just stops moving.

### Re: It's About Time C

Posted: August 5th, 2009, 7:53 pm
scienceolympiadist wrote:Right, T = 2(pi) * (L/g)^(1/2). But eventually, the amplitude becomes so small that it's hard to discern an oscillation. Then, it just stops moving.
Yep, but the longest time trial last year was 5 minutes so you only have to have a discernable oscillation for 5 minutes. It's not hard to do at all.

### Re: It's About Time C

Posted: August 6th, 2009, 7:52 am
Really? I remember I tried something very simple: a string wrapped around a pencil, with a screw at the end of the string. The oscillations dampened after about 10 seconds.

### Re: It's About Time C

Posted: August 6th, 2009, 12:01 pm
scienceolympiadist wrote:Really? I remember I tried something very simple: a string wrapped around a pencil, with a screw at the end of the string. The oscillations dampened after about 10 seconds.
Make sure your string is long enough, and the heavier the weight on the end is, the longer it will take for the pendulum to stop. Make sure that you have a sturdy frame to hold your pendulum on. If your frame isn't sturdy enough, or you just hold it in your hand, the swinging of the pendulum will cause the frame to sway and it will steal some of the kinetic energy which will cause it to dampen faster.