Chemical Clocks

[PM2017]

t does appear that SoCal has issued a state FAQ allowing either approach (altering the chemistry or the associated mechanical action) as valid. It would be extremely helpful to have a national FAQ on this issue (ahem Chalker), however they have been reticent in offering FAQs this year. Hopefully all of this context this helps those who are finalizing designs before the upcoming flood of State tournaments.

This may sound a little irresponsible, as I am the one involved in a SoCal team, and not you, but I can't seem to find a clarification that says this. I used the"Ctrl+f" and typed in chemical, on this page: http://www.socalstatescioly.org/?tab=st ... ifications, but none of them seem to say anything regarding this issue. It doesn't help that the questions are so poorly written either...

Where did you come across this information?

I believe he's citing the question "Are there restrictions on the independent and controlled variables used for the timer demonstration?" If you download the spreadsheet, you'll see that this is a question about rule 4.g.iv.

Ooh. That sounds quite iffy.

[nicholasmaurer]

This may sound a little irresponsible, as I am the one involved in a SoCal team, and not you, but I can't seem to find a clarification that says this. I used the"Ctrl+f" and typed in chemical, on this page: http://www.socalstatescioly.org/?tab=st ... ifications, but none of them seem to say anything regarding this issue. It doesn't help that the questions are so poorly written either...

Where did you come across this information?

I believe he's citing the question "Are there restrictions on the independent and controlled variables used for the timer demonstration?" If you download the spreadsheet, you'll see that this is a question about rule 4.g.iv.

Ooh. That sounds quite iffy.

That is correct. While I agree the FAQ wording is awkward, it essentially means that you can alter any of the variables for the chemical timer, rather than just the chemical process itself (concentrations, temperature, etc.). This would support certain designs that I believe are still questionable nationally without an FAQ.

[Ten086]

So has anyone figured out a way to make a chemical timer if we can’t use electrical sensors...?

[Nletts19]

So has anyone figured out a way to make a chemical timer if we can’t use electrical sensors...?

I’m just using the balloon task as my timer.

[erico.vert]

What reaction are you using for the balloon task then? I tried using baking soda and 5% vinegar and the reaction went too fast to be the timer

[terence.tan]

What reaction are you using for the balloon task then? I tried using baking soda and 5% vinegar and the reaction went too fast to be the timer

try vinegar with lower acidity levels like 3%

[JordanPro]

Many people have been mentioning iodine clocks as a timer. If I could get an infrared laser to shine through the starch solution and then add hydrogen peroxide and the iodine solution to change it to a dark color, could I disrupt the IR beam completing an electrical circuit via a photoresistor to continue onto the next action? Sorry for the length of the question.

[nicholasmaurer]

Many people have been mentioning iodine clocks as a timer. If I could get an infrared laser to shine through the starch solution and then add hydrogen peroxide and the iodine solution to change it to a dark color, could I disrupt the IR beam completing an electrical circuit via a photoresistor to continue onto the next action? Sorry for the length of the question.

Since timers have to be longer than 30 seconds to receive bonus points, and since you can only use electricity in actions lasting less than 10 seconds, I don't think this will work... There is also the 11/14/17 FAQ prohibiting the use of electrical sensors to end timers...

[jinhusong]

My understanding of the sensor ending the timer is you cannot use sensor to end it, but you sure can use a sensor to detect the end of it. You should not adjust the threshold for the time. Of cause, you should not have an internal timer to cheat.

My son's team is using the iodine clock with photo sensor. No problem in Mira Loma and Golden Gate invitations.

[jinhusong]

I feel as long as the ES can see some change, like color, volume, to indicate the end of it.