Designs

[megan]

Sorry to jump into the conversation, but my partner and I are having lots of difficulty with one of our ETS. We're trying to connect a circuit which is connected to a bundle of steel wool wrapped around fishing line. We need the steel wool to catch fire, burn the fishing line, and then the fishing line will melt and release a catapult with one of our golf balls. Anyways, no matter how many times we try, we can't get the steel wool to consistently catch fire, which makes absolutely no sense since its extrememly flammable whenever we try it outside of the circuit (my partner accidentally had our 9-volt battery and steel wool floating around in his knapsack the other day and they caught fire just fine ). We've tried varried amounts and lengths of steel wool but no consistent results. We also know that the circuit is completed and electricity is running through the steel wool (we tested it with a multimeter). At this point, we're thinking it may be because the circuit wears out the 9-volt battery? We've seen a lot of mission possible machines that use a steel wool component, so if anyone has any advice/experience it would be much appreciated!

[Flavorflav]

Several possibilities. Firstly, 9 volt batteries don't hold all that much charge, so you could be encountering that as you suggest. Secondly, how are you completing the contact with the wool? I saw one yesterday which basically rammed the wool with the battery, contacts first. This is not a reliable method. You should have your previous action close a switch which allows current to run through the wool which is firmly attached to two contacts. You could also switch from steel wool to NiChrome.

[blakinator8]

Solo cups, water bottles, 2 liter soda bottles, yoghurt tubs etc. One of them had built little mini jugs complete with handles out of index cards, which of course are not plastic and never contained a beverage. Lots of appeals, all rejected. We did have a nice little discussion about the definition of the word "handle," though.

Did you penalize people who used a milk jug, but cut off the handle portion?

[megan]

Several possibilities. Firstly, 9 volt batteries don't hold all that much charge, so you could be encountering that as you suggest. Secondly, how are you completing the contact with the wool? I saw one yesterday which basically rammed the wool with the battery, contacts first. This is not a reliable method. You should have your previous action close a switch which allows current to run through the wool which is firmly attached to two contacts. You could also switch from steel wool to NiChrome.

Our circuit is set up so that a container is sitting on top of a button, once the container fills with enough sand it pushes down the button which has two wires coming out of it, then we have a 9-volt battery hooked up to one end of the button with an alligator clip, the other end of the 9-volt is attached to a bundle of steel wool (again with an alligator clip), the other end of the steel wool is attached to the final wire on the original button (with an alligator clip). The steel wool section of the circuit is resting atop our fishing line.

What we've found is that if we leave one end of the steel wool unconnected and just tap it with the wire (while holding down the button so the circuit is complete) it lights up perfectly and melts the fishing line. However, when we have the steel wool connected to both wires, it doesn't burn, just creates a safe, non-volatile circuit

Sorry, if this was really confusing to read.

[MP Fan]

Please note that there is no offense taken at all, to the contrary, I and others involved in the rules making are grateful for participants that speak up and point out things that might be confusing or in error. This event is very complicated, and we are still very early in the overall SciOly season, so unfortunately there might still be some 'kinks to work out'. I would suggest sending in additional FAQs, since we can only post updates when they are in direct response to something someone submitted.

Chalker, I've read all the FAQ's and all the recent comments about whether/when the golf ball(s) need to start below the lowest scoring jug and I'm still confused.

Please state whether/when/which golf ball(s) do need to start below the lowest scoring jug and whether/when/which golf ball(s) do not need to start below the lowest scoring jug.

Thank you!

[blakinator8]

Our circuit is set up so that a container is sitting on top of a button, once the container fills with enough sand it pushes down the button which has two wires coming out of it, then we have a 9-volt battery hooked up to one end of the button with an alligator clip, the other end of the 9-volt is attached to a bundle of steel wool (again with an alligator clip), the other end of the steel wool is attached to the final wire on the original button (with an alligator clip). The steel wool section of the circuit is resting atop our fishing line.

What we've found is that if we leave one end of the steel wool unconnected and just tap it with the wire (while holding down the button so the circuit is complete) it lights up perfectly and melts the fishing line. However, when we have the steel wool connected to both wires, it doesn't burn, just creates a safe, non-volatile circuit

Sorry, if this was really confusing to read.

I would recommend getting some of this nichrome wire: http://jacobs-online.biz/nichrome_wire.htm The thinnest gauge they sell worked well for us, with a 9 volt battery, last year. It costs less than $5, including tax and shipping, and it's easy to use- just cut a short length and coil it around the fishing line.

[chalker]

[
Chalker, I've read all the FAQ's and all the recent comments about whether/when the golf ball(s) need to start below the lowest scoring jug and I'm still confused.

Please state whether/when/which golf ball(s) do need to start below the lowest scoring jug and whether/when/which golf ball(s) do not need to start below the lowest scoring jug.

As always, this is not the place for official statements or clarifications. I've provided my insight in various comments above, but if you are looking for more specifics, I'd suggest you submit a FAQ. Note that the question you pose above is pretty broad and generic and won't likely get the answer you seek. You need to ask very specific things typically.

[chalker]

Our circuit is set up so that a container is sitting on top of a button, once the container fills with enough sand it pushes down the button which has two wires coming out of it, then we have a 9-volt battery hooked up to one end of the button with an alligator clip, the other end of the 9-volt is attached to a bundle of steel wool (again with an alligator clip), the other end of the steel wool is attached to the final wire on the original button (with an alligator clip). The steel wool section of the circuit is resting atop our fishing line.

What we've found is that if we leave one end of the steel wool unconnected and just tap it with the wire (while holding down the button so the circuit is complete) it lights up perfectly and melts the fishing line. However, when we have the steel wool connected to both wires, it doesn't burn, just creates a safe, non-volatile circuit

Sorry, if this was really confusing to read.

The reason likely has to do with surface area of the electrical contacts. By using big alligator clips you are essentially 'spreading' the current out across lots of strands of the steel wool. Instead you want the current to be focused through just a very few strands.

[Flavorflav]

Solo cups, water bottles, 2 liter soda bottles, yoghurt tubs etc. One of them had built little mini jugs complete with handles out of index cards, which of course are not plastic and never contained a beverage. Lots of appeals, all rejected. We did have a nice little discussion about the definition of the word "handle," though.

Did you penalize people who used a milk jug, but cut off the handle portion?

No, that is explicitly allowed by rule 4.a.2, as long as there is 10 cm of jug left.

[Flavorflav]

Please note that there is no offense taken at all, to the contrary, I and others involved in the rules making are grateful for participants that speak up and point out things that might be confusing or in error. This event is very complicated, and we are still very early in the overall SciOly season, so unfortunately there might still be some 'kinks to work out'. I would suggest sending in additional FAQs, since we can only post updates when they are in direct response to something someone submitted.

Chalker, I've read all the FAQ's and all the recent comments about whether/when the golf ball(s) need to start below the lowest scoring jug and I'm still confused.

Please state whether/when/which golf ball(s) do need to start below the lowest scoring jug and whether/when/which golf ball(s) do not need to start below the lowest scoring jug.

Thank you!

I'll give you my 2 cents, if you like: a golf ball must start below the lowest scoring jug to be eligible to earn 2 points, but any golf ball may be used to initiate or complete an ETS.

BTW, Chalker, why do the rules say no impound at Regional? Every competition I have been to or heard about has added it back in. I honestly don't see how you could do any reasonable number of devices without an impound.