Mission Possible C

[andrewwski]

Hey I have a really quick question for everyone, is propane a hazardous liquid?

At STP? No, it's a flammable gas. Compressed? Then it's a liquid. It does appear on the Right-to-Know hazardous substance list...

The standard warning about this not being the place for official clarifications aside, I would not advise you to use propane. I cannot think of a safe way to use propane in this event.

[Plaid Suit Guy 3]

So, the rules state the following:

Mission Possible (9/13/13) 3.i should read: "Only wires, batteries, photo cells, photosensors (e.g., photovoltaic cells, photodiodes, photoresistors, phototransistors), light bulbs, LEDs, homemade solenoids, switches, and up to three motors may be used in the device. No computers, integrated circuits or other electric components are allowed.

Does that mean that no resistors are allowed?

[Kordo]

Answering what a transfer is would be just restating the rules, it probably won't be addressed by any of the national judges. Once you have been in the event and competed you will understand what I mean. This event probably has the greatest learning curve of all of the events. Let me give you an example of a transfer with the list to see if this helps. Suppose I have a light switch wired to a DC motor which when turned on turns a threaded rod that will slide a nut along the rod which flips another switch turning on a light. This would be mechanical (flip switch) to electrical (motor) to mechanical (Rod turning moving the nut) to mechanical ( flip switch) to electromagnetic (light). You would write this as mechanical to electrical, electrical to mechanical, mechanical to mechanical (no points), mechanical to electromagnetic. If anybody thinks I am in error on this let me know but I am very sure this would be an accurate TSL for the described tasks. Notice that I do have a Mech. to Mech. listed and it would have to be on the TSL but would not be given any points but without that transfer you could not get from the initial flip of the switch to the light turning on (this is what they mean in 3h). I hope this helps.

[gorf250]

Answering what a transfer is would be just restating the rules, it probably won't be addressed by any of the national judges. Once you have been in the event and competed you will understand what I mean. This event probably has the greatest learning curve of all of the events. Let me give you an example of a transfer with the list to see if this helps. Suppose I have a light switch wired to a DC motor which when turned on turns a threaded rod that will slide a nut along the rod which flips another switch turning on a light. This would be mechanical (flip switch) to electrical (motor) to mechanical (Rod turning moving the nut) to mechanical ( flip switch) to electromagnetic (light). You would write this as mechanical to electrical, electrical to mechanical, mechanical to mechanical (no points), mechanical to electromagnetic. If anybody thinks I am in error on this let me know but I am very sure this would be an accurate TSL for the described tasks. Notice that I do have a Mech. to Mech. listed and it would have to be on the TSL but would not be given any points but without that transfer you could not get from the initial flip of the switch to the light turning on (this is what they mean in 3h). I hope this helps.

I agree mostly with this (ignoring some interpretations of the seemingly mythical "blackbox rule"), but am confused as to why the first time you use a switch, you call it mech to electrical, but the second time you call it mechanical to electromagnetic. It would seem that you skipped the electricity the second time.

[Kordo]

In the first case the electricity is running the motor, the second time the electricity is creating light. The black box in both cases would be the battery, you cannot count the chemical reaction because you didn't create it (if you used a lemon and made a battery then you could count it). In the first case there are technically more transfers than mechanical to electrical to mechanical, but the motor has always just been an electrical use. If you look at the flow through the transfer try to think of it like the switch is MOVED, starting ELECTRICITY running the motor, the motor MOVES the threaded rod and the nut. You could actually write the rod turning causing the nut to move as a mech to mech and probably should to avoid the possibility of getting dinged on the TSL. If you were to try to count the transfers through the battery motor I would not accept it. A motor would not count as electromagnetic unless you make it just like the battery/lemon scenario.

[gorf250]

In the first case the electricity is running the motor, the second time the electricity is creating light. The black box in both cases would be the battery, you cannot count the chemical reaction because you didn't create it (if you used a lemon and made a battery then you could count it). In the first case there are technically more transfers than mechanical to electrical to mechanical, but the motor has always just been an electrical use. If you look at the flow through the transfer try to think of it like the switch is MOVED, starting ELECTRICITY running the motor, the motor MOVES the threaded rod and the nut. You could actually write the rod turning causing the nut to move as a mech to mech and probably should to avoid the possibility of getting dinged on the TSL. If you were to try to count the transfers through the battery motor I would not accept it. A motor would not count as electromagnetic unless you make it just like the battery/lemon scenario.

If you can't count a battery because you didn't make it, why is it that you can count the motor if you didn't make it?

Furthermore, in your original scenario, you count the second switch as mechanical to electromagnetic spectrum. Why is it not mechanical to electrical to electromagnetic spectrum? The first switch you counted as mechanical to electrical to mech, so why did you ignore the electricity the second time?

[Kordo]

The battery combined with the motor are considered electrical. I have seen the switch to battery to light combined counted as mech to elect. to em. I would suggest asking a clarification to see how the writers recommend this be scored. Until then I suggest playing it safe and count only the light as what you are using to start your next transfer. If you were using the heat from the bulb to start your next transfer you would thermal instead of em. In the rules em is radio, infrared and visible light only.(3e) The motor can only be used as electrical and has always been accepted as an electrical. I know it takes a while to get clarifications but they are the only way to assure how you are scored so make sure you go through the process, they do go over all of the questions asked.

[olympiaddict]

Agreed, clarifications are the way to go. However, unfortunately, i and others submitted clarifications about this when they first opened up and haven't gotten a response so that's why we turned to discussion here

[jroorda]

My students are also waiting on clarifications. I see one major clarification needed in regards to energy transfers.

One could interpret energy transfer in two ways. First, that to be a scoreable energy transfer one must actually convert joules of energy from one form to another. With the term "Energy Transfer" used so much in the rules I could easily see this interpretation being used at our regional unless things are clarified further. Alternatively, one could interpret a transfer as transferring the "signal" (chain of events) from one basic energy from to another. Mandating that a quantity of energy be transferred makes this event much harder, but not impossible. It does not limit one to the energy of the starting event as some have suggested because one can always add non-scoring steps that add more energy between the scoring steps. For instance, an electrical switch would not score as Mech -> Elec. under the first system because none of the mechanical energy that enters the switch leaves as electrical energy, but it still could be used to switch on a motor that converts electrical to mechanical. Similarly, uncovering a light source would not transfer Mech -> Light, but a solar cell could then covert light to electricity. Under the second interpretation all of these would be valid transfers. Hopefully we will soon see this clarified. I suspect the soon-to-be-posted ETL will use transfers that would not be valid under the first interpretation, but I could certainly be wrong.

On the other longstanding debate. I think homemade batteries will be allowed via a FAQ, but until then they could be disqualified. I also would not count a commercial battery as Chem -> Elec not because it is not student made, but because prior to the start of the event the battery already had a voltage difference between the poles which represents a preexisting electrical potential. To count as Chem -> Elec in my book one would need to assemble the battery during the run, so a new electrical potential is created. In other words, to count as Chem to Elec. one must alter the chemistry on the input side.

The "black box" rule in my book only states that all transfers must be visible (as stated in the rules). To extend it beyond this would be reading something into the rules that just doesn't seem to be written there. That said, this is at the discretion of the event supervisor so I would check with them prior to each competition whenever possible.

[olympiaddict]

A thorough but to the point analysis of the major clarification issues we need help with. Thank you!