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Re: It's About Time C

Posted: February 17th, 2010, 7:21 pm
by walkingstyx
Yeah, K'nex and final devices rarely mix well. Also, you might want to try increasing the weight at the bottom to increase the duration. It won't change the period, but it will give it more inertia and decrease the damping factor. You could also try pulling it back a greater angle to start with. Thirdly, when you build it with wood use a bearing or lots of lubricant or something else to decrease friction.

Re: It's About Time C

Posted: February 18th, 2010, 6:17 pm
by Bogoradwee
walkingstyx wrote:Yeah, K'nex and final devices rarely mix well. Also, you might want to try increasing the weight at the bottom to increase the duration. It won't change the period, but it will give it more inertia and decrease the damping factor. You could also try pulling it back a greater angle to start with. Thirdly, when you build it with wood use a bearing or lots of lubricant or something else to decrease friction.


Is the K'nex part only in reference to pendulums? B/c I made a sand thing involving spinning spoons, and the K'nex work wonderfully. It's a standardized unit and it's very pretty and colorful lol

Re: It's About Time C

Posted: February 18th, 2010, 7:05 pm
by Gooblah
Few other quick questions:

1) Would one be allowed a calculator, if an irregular period (as invariably would happen) existed for counting purposes?
2) How would one measure tenths of a second with a pendulum? It seems like one would be just guessing at some point...

Re: It's About Time C

Posted: February 18th, 2010, 7:16 pm
by Bogoradwee
seeing as i haven't tried a pendulum, i can't entirely answer your pendulum question, but i can imagine that they could have attached some thing that the pendulum's path would line up with and it could have markings, allowing specific regions to be specific tenths of seconds.

Re: It's About Time C

Posted: February 19th, 2010, 7:22 am
by Gooblah
Bogoradwee wrote:seeing as i haven't tried a pendulum, i can't entirely answer your pendulum question, but i can imagine that they could have attached some thing that the pendulum's path would line up with and it could have markings, allowing specific regions to be specific tenths of seconds.


That's what I was thinking, but considering the angle changes every time the pendulum completes a period...i guess it could be possible to remember the starting angle and then calculate from there....

Re: It's About Time C

Posted: February 19th, 2010, 10:08 am
by Primate
Gooblah wrote:1) Would one be allowed a calculator, if an irregular period (as invariably would happen) existed for counting purposes?
Nope, you're not allowed to use a calculator at all for the first part of the competition. It's really dumb in my opinion--if you can use an electronic balance for a water clock, why can't you use a four-function calculator for the pendulum? It's not that difficult to just multiply it out, though, in the minute you get between launches. Just make sure you double check.

Now, the first year I did this event, I neglected to read the rules where it said you couldn't use a calculator for Part I. And apparently so did the event supervisors at regionals, so I got away with using it. Ironically, this year, the regionals guy was even worse. The test said "only four-function calculators allowed" (and this is one of the few events where you can use a graphing calculator), but when I told him he could have cared less. He forgot to impound watches, too, until I reminded him...

Gooblah wrote:2) How would one measure tenths of a second with a pendulum? It seems like one would be just guessing at some point...
Yeah, it is. You can get pretty accurate, though, because of the way period is measured. Say you've got a pendulum with a period of exactly one second. (It's a little unrealistic to calibrate something so precisely, but it would be about 10 inches long.) That means that the outswing is half a second, and the backswing is half a second. You can easily subdivide these in half, because you can see if it's passed the equilibrium position or not.

That's an error of .25s at most, which isn't bad at all for the last four trials. For the first trial, you might want to use a pendulum with a period of half a second, which means your error would be around .125s. Conservatively, We'll say the average error is somewhere around .2 seconds per trial, except for the first. Scoring that yields (1 * .4) + (2 * .3) + (2 * .2) + (2 * .1) + (2 * .1) = 1.8, giving you a score of 48.2. That's a win at regionals.

Bogoradwee wrote:seeing as i haven't tried a pendulum, i can't entirely answer your pendulum question, but i can imagine that they could have attached some thing that the pendulum's path would line up with and it could have markings, allowing specific regions to be specific tenths of seconds.
You could definitely experiment with something like this, but I would say don't bother. You just won't have time to make such an intensive calculation in a minute. I wish you could bring a chart or something, but you'd have to bring one for each angle--that's like 45 of them. Spending some quality time with your pendulum will be much more beneficial in the long run. You'd be surprised how accurate you can be once you get to know it.

Re: It's About Time C

Posted: February 20th, 2010, 1:33 pm
by genesys
i am very confused with all of this its about time can you please help me as in today with all of this i really need to paass the tests!!!!

Re: It's About Time C

Posted: February 20th, 2010, 2:32 pm
by Sir_L_Jenkins
Unfortunately, it takes time to master time. Unless you have a fancy ocarina, you may be out of luck.

However, if you're looking for some quick resources, wikipedia's good for quick binder making, and maybe some physics review of some mechanics. Otherwise just look at the topics in the rules and search around for that stuff. The official SO site also has some decent resources

Re: It's About Time C

Posted: February 20th, 2010, 9:21 pm
by walkingstyx
genesys: please do not troll. Even if it were possible for several anonymous strangers who post irregularly to prepare you in a single day for an event that requires intensive studying, it would not be nearly as effective as you actually going out and learning information yourself. Additionally, the members of this forum have already complied with your request as much as possible with the creation of the wiki, which is displayed prominently at the top of your screen. Please keep in mind that all forum posts should have a legitimate purpose. Shouting in large red lettering has no possible purpose but to annoy others.

Re: It's About Time C

Posted: February 21st, 2010, 7:49 am
by Bogoradwee
Sir_L_Jenkins wrote:Unfortunately, it takes time to master time. Unless you have a fancy ocarina, you may be out of luck.

However, if you're looking for some quick resources, wikipedia's good for quick binder making, and maybe some physics review of some mechanics. Otherwise just look at the topics in the rules and search around for that stuff. The official SO site also has some decent resources

1. you sir, have just been awarded one internet.
2. the official SO site is VERY helpful.

Re: It's About Time C

Posted: February 21st, 2010, 10:01 am
by SRBHAR01
My invitational test had physics problems like velocity and acceleration.. Which was stupid plus we had to wait 1 hour for the event started so i missed my 2nd event .

Re: It's About Time C

Posted: February 21st, 2010, 10:21 am
by Bogoradwee
SRBHAR01 wrote:My invitational test had physics problems like velocity and acceleration.. Which was stupid plus we had to wait 1 hour for the event started so i missed my 2nd event .

why did you have to wait an hour?

Re: It's About Time C

Posted: February 21st, 2010, 2:36 pm
by Ostonzi
Paradox21 wrote:We had our regional competition on Saturday in Minnesota (not the most competitive state) and I got to see the raw scores for the event and I was amazed at the scores for the time trials. There were at least 5 teams within a 48/50 for the trials. The deciding part really seemed to be the test. Out team got 5th in the time trials with a low 48 score (48.3 I think) but got 1st overall because we did well on the test. As far as I know all of the designs were relatively simple pendulums.


Roflmao. We got 3rd. Where were you guys sitting lol?
Did you guys finish the test? rofllll our water clock thing was just pouring water and watching it. it was so terrible. thank god im not doing this event again.

Re: It's About Time C

Posted: February 23rd, 2010, 12:42 pm
by genesys
:roll: :roll: ]Excuse me walkingstyx. Take no notice on what i put and ill have you know ill do good and i do study okay i just have some certain few problems on some stuff. But thanks anyways for your ubnoxious comment on my big red letters , it is for what i say to catch peoples attention.:/ thank you again so long.

Re: It's About Time C

Posted: February 23rd, 2010, 8:07 pm
by Scrufficus
Hello all. This is my first year in Science Olympiad and i was just wondering if any of you guys could give me some good resources to study from. It would be greatly appriciated.