Junkyard Challenge C

[trombonegirl23]

What about a spring? Like a spring scale?

[maggymay]

Our scale is so simple, but we didn't use a spring - sorry I can't help.

Regional was so much easier than having to have 2 ADs ready to go for State - ugh.

I have a question about the coin sorter. Can someone confirm for me that at the State competition, the coins can be fed into the sorter one at a time? I was reading the rules for State and it looks like they don't HAVE to be dumped all at once, they can be dropped into the sorter one at a time.

Thanks.

Oh and good luck trombonegirl23.

[Uncle Fester]

Well, Culebra, it's been quite a while since you've posted. Welcome back.

Event only tests ACCURACY, and not PRECISION. Accuracy is described (simply) as "how close your measurement is to perfection". PRECISION is "repeatabilily of a given measurement", or, put in even simpler terms, "how close multiple measurements are to each other". Since teams placed and measured the mass only once, there's no way possible for precision to be measured, or even estimated. I suppose precision-related data could be collected by requiring a logbook like Wright Stuff, but how many (including me) have fudged data in a logbook? Same-sized objects with different densities could be used, but knowledge of purpose would render "collected data" rather suspicious, to say the least.

I fully expected certain teams to howl about MY accuracy the moment they found out they didn't win. [Pleasantly surprised to find this didn't happen] With some time off from the tail end of the flu and contacts at the met lab of a nuclear power plant I have access to, between a direct NBS mass and a very expensive scale I was able to borrow, I had a known mass within 5mg, even after transferring measurements from standard to scale to test mass.

I discussed buoyancy with the crew. Their initial response was, "Who's going to ask, besides an irate paent wanting to show off and then try to BS a win?" Solution was simple-- Find an object that was relatively porous, with included air an integral part of the object. Ta-daa, cut the error by half-- or more. The more I think about it, the higher I suspect the percentage of trapped air is. I suppose I could take the package, soak it in water (gross) and reweigh it to determine the actual amount of air held captive inside to determine the exact error, but I'm not THAT bored.

Asa far as the real world goes, all the teams except ONE did a certain amount of estimation, guesswork, fudging, whatever. How much, only they know. So really, is buoyancy going to have even the slightest effect on anyone's score? The only one that didn't have an estimation was the inertial scale; they showed me their procedure, collected the date, and ran it through their formula, writing down their answer while I watched-- and they didn't win. In short, I'll bet a paycheck on my accuracy.

[trombonegirl23]

In the Rules its says that you get a point deduction for touching it. Are you allowed to put the mystery object on and then touch something so it activates and starts doing what ever it does to measure it?

[jazzy009]

the mystery object will be put into your device during the building time (approx 30 minutes) then during testing time (ten minutes) you can do whatever last minute adjustments you need and then start the device with something like a pencil...just not you hand or a human body part, then it isnt autonomous. your hand can hold the pencil or push a button, obviously. an example: you have a spring scale and to start it you place the object to be weighed in a basket and lower it with your hand until the spring is holding all the weight...BAD!!!

[maggymay]

You have 30-45 minutes to put your Junkyard Challenge object together. During that construction time you integrate the Mystery Object into your Autonomous Device. You *cannot* touch your AD, once the Assessment part of the Olympiad has started, in any way other than an allowed way. (For instance, in EV, the competitors are only allowed to start the car using a dowel or pencil to push the start button.) With the Coin Sorter, every time you touch the AD, I think you get a deduction. I'm not sure about your turning on the AD and then touching something on the AD so the device will actually work. I think you need to contact your State coordinators to make sure.

(Or you could just decide to take the deduction if everything else on your AD works.)

[call4angel]

http://fotos.fotoflexer.com/28f3d6ffa41 ... cdfca8.jpg

is this a valid design?!?!
im so confused...

[DeltaHat]

http://fotos.fotoflexer.com/28f3d6ffa41 ... cdfca8.jpg

is this a valid design?!?!
im so confused...

Should work. Looks good to me.

[jazzy009]

wait. wouldnt looping the wire through the black thing decrease the amount of weight applied to the spring (i would assume by half) and therefore give you less accurate results? it seems like it would act like a pulley...?

[Flavorflav]

It is a pulley, but it has an IMA of one so it would decrease the force only by the amount of friction, not by half. A question, though - if you have to measure displacement with a ruler, is that considered autonomous? Or do you have to build a ruler into the device?