Bungee Drop C

[BuildistFromTheNorth]

Obviously it would be really nice to have a standard drop mech in the rules but since that hasn't happened the least proctors could do for all competitions (specifically for states and Nats) is post a video of how it works. I remember seeing pictures for the drop mech last season and often times it was unclear what was happening...

[blindmewithscience]

So, what materials have been successful in the past? Our previous year's sadly team did nearly no preparation for this event, and the wiki is dismally devoid of information. Also, would you recommend having multiple of the same cords, so that any effects of the cord stretching over the course of a year is minimized?

[JonB]

So, what materials have been successful in the past? Our previous year's sadly team did nearly no preparation for this event, and the wiki is dismally devoid of information. Also, would you recommend having multiple of the same cords, so that any effects of the cord stretching over the course of a year is minimized?

I think many different materials can work for this event. This event seems to be inherently inconsistent (somewhat) despite the materials. I believe this is definitely an event where trial after trial after trial is required. It wouldn't hurt to make a couple of the same bungee and then test- that should tell you if your material is going to stay consistent over time (it probably wont if you keep it all year...).

[liamafrost1]

Does anyone know where to get elastic bang or metal springs that will meet the required k value, i cant seem to find a meter or more elastic material of any kind that has an appropriate k value for the event. Last I could not find anything that was a meter long so i had jerryrig 5 rubber bands tied together. Our testing was incredibley inconsistent, we need a new material and i cant seem to find anyhting on line or in the area that will work. Does anyone have any ideas.

[blindmewithscience]

My team is currently in the process of testing different materials. We're looking at fabric elastic, contest rubber, and latex surgical tubing. The fabric elastic you can get from local craft/fabric shops, the contest rubber from hobby shops (they're mainly used in things like balsa wood airplanes), and latex tubing from stores like Walmart. You can also get any of these online, and you can get them in fairly large sizes.

[chalker]

Does anyone know where to get elastic bang or metal springs that will meet the required k value, i cant seem to find a meter or more elastic material of any kind that has an appropriate k value for the event. Last I could not find anything that was a meter long so i had jerryrig 5 rubber bands tied together. Our testing was incredibley inconsistent, we need a new material and i cant seem to find anyhting on line or in the area that will work. Does anyone have any ideas.

One item you can try is Therabands (used in most Physical Therapy clinics), which come in different resistances. You could try asking for some for free from a local PT clinic or maybe even the athletic trainer at your school. If you want to buy them, they are available at a lot of places, such as Amazon:
http://smile.amazon.com/Thera-Band-Extr ... therabands

P.S. - if you shop Amazon, please consider using Amazon Smile (smile.amazon.com). The prices are the same, but a portion of your purchase goes to a charity of your choice. And Science Olympiad is one of the charities you can choose!

[Nate711]

Hi. I'm wondering if for the elasticity test the proctors hold the cord from the 1m mark and then apply the mass or if they hold the cord from a different place. The rules say the bottom meter is suspended vertically, but it doesn't explicitly say where it will be held from. (I submitted a FAQ, but no response yet). Thanks!

[chinesesushi]

Hi. I'm wondering if for the elasticity test the proctors hold the cord from the 1m mark and then apply the mass or if they hold the cord from a different place. The rules say the bottom meter is suspended vertically, but it doesn't explicitly say where it will be held from. (I submitted a FAQ, but no response yet). Thanks!

What do you mean hold the cord from a different place. The bottom meter (which includes the key ring) should stretch to 1.25 meter or more.

[Nate711]

As in, at which point do they attach the cord to the wall (or stairwell etc)?

[blindmewithscience]

As in, at which point do they attach the cord to the wall (or stairwell etc)?

I assume that they'll take the point that's one meter away from the bottom, attach it to something or hold it, and then attach the 500g mass. Could you explain how the judges could measure how far the bottom meter stretched if they held somewhere other than the bottom meter?