It's About Time C

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Re: It's About Time C

Postby Science Zone » January 23rd, 2010, 10:12 am

Can i get a practice test for It's about time. thanks in advance ;)

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Re: It's About Time C

Postby Primate » January 23rd, 2010, 8:19 pm

events 2012 gravity vehicle, robot arm, thermodynamics, tps

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Re: It's About Time C

Postby Melkor6000 » February 7th, 2010, 2:01 pm

Here's an idea that my school might end up using at states.

A Stirling Engine converts ambient heat into kinetic energy in a flywheel via volumetric changes in a cylinder, and a temperature differential between a hot and a cold chamber. If you built a Stirling engine (very precisely, or course, since they are notoriously persnickety to build) and embedded the cold chamber in a cooler of ice, and focused a parabolic mirror onto the hot chamber, the resulting difference in temperature should be enough to get things moving. All you'd need to do was come up with a way to gear it down to read the time more accurately. So essentially, you'd impound a camp oven and a cooler of ice : )

Any thoughts?
2007-2008 Regionals: Boomilever (3rd), Environmental Chem (5th)
2008-2009 Regionals: Fossils (4th), Physics Lab (4th), Alternative Energy (2nd)
2009-2010 Regionals: Astronomy (1st), Fossils (3rd), Mission Possible (6th), Physics Lab (1st), Trajectory (2nd)
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Re: It's About Time C

Postby rockhound » February 7th, 2010, 4:14 pm

Melkor6000 wrote:Here's an idea that my school might end up using at states.

A Stirling Engine converts ambient heat into kinetic energy in a flywheel via volumetric changes in a cylinder, and a temperature differential between a hot and a cold chamber. If you built a Stirling engine (very precisely, or course, since they are notoriously persnickety to build) and embedded the cold chamber in a cooler of ice, and focused a parabolic mirror onto the hot chamber, the resulting difference in temperature should be enough to get things moving. All you'd need to do was come up with a way to gear it down to read the time more accurately. So essentially, you'd impound a camp oven and a cooler of ice : )

Any thoughts?


When you say "camp oven" are you refering to the parabolic mirror or something else? Can a parabolic mirror heat something from flourescent lights?

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Re: It's About Time C

Postby Melkor6000 » February 8th, 2010, 4:50 am

rockhound wrote:
Melkor6000 wrote:Here's an idea that my school might end up using at states.

A Stirling Engine converts ambient heat into kinetic energy in a flywheel via volumetric changes in a cylinder, and a temperature differential between a hot and a cold chamber. If you built a Stirling engine (very precisely, or course, since they are notoriously persnickety to build) and embedded the cold chamber in a cooler of ice, and focused a parabolic mirror onto the hot chamber, the resulting difference in temperature should be enough to get things moving. All you'd need to do was come up with a way to gear it down to read the time more accurately. So essentially, you'd impound a camp oven and a cooler of ice : )

Any thoughts?


When you say "camp oven" are you refering to the parabolic mirror or something else? Can a parabolic mirror heat something from flourescent lights?


Well, that's one thing we're going to test, whether a arabolic mirror can be focused on a 60 or 70 Watt bulb at several feet and have a noticeable difference. It could be that the ice itelf is enough
2007-2008 Regionals: Boomilever (3rd), Environmental Chem (5th)
2008-2009 Regionals: Fossils (4th), Physics Lab (4th), Alternative Energy (2nd)
2009-2010 Regionals: Astronomy (1st), Fossils (3rd), Mission Possible (6th), Physics Lab (1st), Trajectory (2nd)
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Re: It's About Time C

Postby walkingstyx » February 8th, 2010, 3:53 pm

That idea sounds incredibly cool, but not especially good at keeping time. It sounds as though ambient temperature differences could have a huge impact on how well this clock worked, not to mention how difficult it would be to build and the likelihood of it being destroyed in travel. Awesome ideas are fun, but only if they work well. If your goal is to win, I would suggest going with a simple natural harmonic oscillator and calibrating it to death. Our device for Nats last year was a pendulum and Troy's (the winners) was an oscillating spring. Both were very simple, but their operators knew them well enough to keep virtually perfect time. Also, simple devices tend to travel better. Our pendulum survived a car wreck on the way home from State, while some of our complex devices can hardly handle being picked up in the classroom.
Nationals 2010- Astronomy: 4, Physics Lab: 4, Picture This: 4, It's About Time: 10, Optics: 2
Nationals 2009- Picture This: 4, It's About Time: 8, Astronomy: 9
Nationals 2008- Picture This: 2, Boomilever: 14

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Re: It's About Time C

Postby Paradox21 » February 8th, 2010, 6:40 pm

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.
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Re: It's About Time C

Postby texan92 » February 8th, 2010, 6:56 pm

That idea sounds incredibly cool, but not especially good at keeping time. It sounds as though ambient temperature differences could have a huge impact on how well this clock worked, not to mention how difficult it would be to build and the likelihood of it being destroyed in travel. Awesome ideas are fun, but only if they work well. If your goal is to win, I would suggest going with a simple natural harmonic oscillator and calibrating it to death. Our device for Nats last year was a pendulum and Troy's (the winners) was an oscillating spring. Both were very simple, but their operators knew them well enough to keep virtually perfect time. Also, simple devices tend to travel better. Our pendulum survived a car wreck on the way home from State, while some of our complex devices can hardly handle being picked up in the classroom.


Did your pendulum have an escapement?

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Re: It's About Time C

Postby Jazzy09 » February 9th, 2010, 8:44 pm

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.


lololol that is not true
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Re: It's About Time C

Postby Flavorflav » February 10th, 2010, 7:48 am

Jazzy09 wrote:
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.


lololol that is not true

Do you mean that they didn't have their regional competition Saturday, or that it wasn't in Minnesota?

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Re: It's About Time C

Postby Paradox21 » February 10th, 2010, 3:59 pm

No, the scores seemed a little dubious so we looked into it and the scoring was done incorrectly. A team that was .9 seconds off on the 1st time trial would have been docked .9(.4) or .36 but they should have been docked 9(.4) or 3.6 points. It ended up changing some of the overall placements but our team got 1st either way. And it has been reaffirmed, MN is not the most competitive state.
When it comes to the future, there are three kinds of people: those who let it happen, those who make it happen, and those who wonder what happened.

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Re: It's About Time C

Postby walkingstyx » February 10th, 2010, 5:35 pm

Yeah that seemed a little odd, we just won an Ohio invitational with a low 48. Also texan92 we did not have an escapement, we just knew how much our period decayed by.
Nationals 2010- Astronomy: 4, Physics Lab: 4, Picture This: 4, It's About Time: 10, Optics: 2
Nationals 2009- Picture This: 4, It's About Time: 8, Astronomy: 9
Nationals 2008- Picture This: 2, Boomilever: 14

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Re: It's About Time C

Postby saturnian » February 11th, 2010, 7:14 am

walkingstyx wrote:That idea sounds incredibly cool, but not especially good at keeping time. It sounds as though ambient temperature differences could have a huge impact on how well this clock worked, not to mention how difficult it would be to build and the likelihood of it being destroyed in travel. Awesome ideas are fun, but only if they work well.


While some event supervisors may overlook use of electric bulb to create "heat" chamber, it is surely against the rules (no electricity or chemicals). But I agree, the idea is pretty awesome.

Last year, one of my teammates tried to do magnetic device. It was pretty cool too, but did not quite work, and if you think about it - against the rules, since magnets create electromagnetic fields. She was never questioned during invitationals, but once you get to states or nationals, event supervisors may DQ your "clock".

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Re: It's About Time C

Postby saturnian » February 11th, 2010, 7:18 am

walkingstyx wrote:Yeah that seemed a little odd, we just won an Ohio invitational with a low 48. Also texan92 we did not have an escapement, we just knew how much our period decayed by.


You guys were great, and we are happy you could come. Hope you enjoyed the snow :)

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Re: It's About Time C

Postby Gooblah » February 17th, 2010, 9:23 am

What materials did you guys use for pendulum construction?

I tried using a 1/4 diam, 3 in. bolt as the axis, and then hooked that up to a Knex frame for support. Hanging from it was a 1/4 threaded rod that ended in an eyehook, which had about 9 oz attached to it. However, all I'm getting out of the pendulum is ~1.5 mins, way too short for competition.

I'm thinking the time issue is coming from several locations:
1) Dampening of momentum due to frame sway
2) Friction between the axis and the pendulum itself (I used a small knex contraption, with two knex pieces hanging off the axis and then connecting to the pendulum)
3) Air resistance

Issue #1 can be resolved by replacing the frame with wood, I think - currently, it's a wooden base, and then a knex frame is screwed onto it. So by replacing the knex frame with two pieces of wood, i could effectively reduce frame sway.

Issue #3 is negligible, since the pendulum isn't particularly wide.

I tried using string tied to the weight on one end and a simple washer on the other to reduce friction, but the weight simply snapped the string. I'm considering looking into fishing twine or a thing metal rod which I could bend with pliers to replace the threaded rod in the pendulum. Any suggestions?
Events: Remote Sensing, Chem. Lab, It's About Time, Dynamic Planet, Mission Possible, Env. Chem. The latter two I found out I had to do 4 weeks before Regionals. Fun, fun, fun.


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