Scioly.org

I did some testing with my thermo device and was wondering if my results were good. The starting temperature was 70.3 degrees and after 20 minutes fell to 64.3 degrees. After that point the device lost about .2 degrees/minute and after 30 minutes lost 62.4 degrees. Are these results good?

nahor.ah wrote:I did some testing with my thermo device and was wondering if my results were good. The starting temperature was 70.3 degrees and after 20 minutes fell to 64.3 degrees. After that point the device lost about .2 degrees/minute and after 30 minutes lost 62.4 degrees. Are these results good?

What was the volume of water? 100 mL?

Yes, the colume was 100 mL.

Was the 70.3 degrees measured before you poured the water in or after?

The 70.3 degrees was measured after I put the water in.

Had an invitational today, and they measure the water temp before pouring the water. So for a more accurate prediction make sure to measure the water temp before putting the water into your device.

CPScienceDude wrote:Had an invitational today, and they measure the water temp before pouring the water. So for a more accurate prediction make sure to measure the water temp before putting the water into your device.

I would measure the water temp after putting it in and then remeasure it after they put it in at the invitational... at least that's what I did last year

UTF-8 U+6211 U+662F wrote:

CPScienceDude wrote:Had an invitational today, and they measure the water temp before pouring the water. So for a more accurate prediction make sure to measure the water temp before putting the water into your device.

I would measure the water temp after putting it in and then remeasure it after they put it in at the invitational... at least that's what I did last year

Also agree. The people who run the invitational do this because of rule 4.b., especially because it deals with a source bath. However, do to changes in the environment you are in, it's important to also measure inside your device. As previously mentioned, you lose a lot of heat between the soure bath and your device. Because you are in a different space than you do trials in, you should measure both so you can base your predictions off of that. In fact, we do our predictions mostly based on the initial temperature within our device, simply because that temperature will vary even with the same temperature in the source bath.

i want to ask a similar question...
I used 100 mL of water, the source temp was about 63 deg C (only 1 thermometer and did not measure too accurately). The 1st reading in the device was 57.7, which then dropped down to 50.0 after 30 minutes. The air temperature is about 19 deg C (cold house), which is a k-constant of about .00739. I'm considering building a new device with different materials, but am not sure if I will have the time due to work. Should I? If not, are there any quick ways to increase the heat retention so I can lower my k-constant (since it actually counts this year)?

Yes, it is a good k score, but you mean -0.00739, right? To improve your k score, I mean you can't do much other than making a new device. Try using the cotton ball to its full extent. Also, do multiple tests before evaluating your k score. But that is quite a good k score, the best ones are on the order of -0.004.