To Do
Ice Machime
- The electronic ice machines came in yesterday and I have been messing with them since
- They are set to be @ 3°C
- They use these "Miracle Beads" instead of ice to absorb the heat
- We left one on overnight filled 80% with beads with a centrifuge tube with tap water.
- Today, it is hovering about 6-7°C which Koch thinks is alright
- The display says its at 3C and using the temp probe we have, the block is 3-4C
- Things to try:
- Leave the lid off (Koch's Idea). Makes more of a thermal gradient, perhaps causing the block to work harder and cool the beads all the way through
- Too many beads, use less beads (Q=mc(delta)T, so if Q is constant, less m = more delta T)
- Beads + water. The booklet says that this causes the thing to cool faster (1hr instead of 2hrs for beads only)
Trials
- The removal of the lid did nothing to cool down the sample more (on a bright note, it didn't heat up the sample more)
- Running the other ice bucket "naked". The cooling surface got down to 0C (even though the display read 7C)
- Trying something: I put some water from the real ice bucket in the fridge into a tube. The probe said that the fridge water is at 3C. Put the lid on the beads bucket and going to see if the water heats up in about 10mins (if it stays 3C then stuff from the fridge can go in w/o risk of overheating)
- So I guess the 0th law of thermodynamics is still true. Beads 7C, water 7C
- With the 2nd bucket, I have allowed it to cool to a reading of 4C naked. I placed the aluminum pan into the 4C Fridge (reading of 6-7C when removed) and placed that into the 2nd bucket. I will see how cold it gets with just pan (closed lid)
- The display reads 4C and the temperature of the pan (the probe is inside touching the pan with the lid closed) is reading 4C.
- Next thing to try: beads plus water. Filling the empty pan with about the same amount of beads as the first with ~250ml of h20 (tap, since DI water will eat the Al pan)
- So far, I've put 250ml of water into the pan. I'm going to wait a while to see if the machine can bring down that water to 3c (my thinking is that there only a set amount of cooling that this thing can do and if you overload it then the min temp is above 3c)
- About 10 mins in, the display says 7C and the water is at 11C
- 20 more mins (or so) and the reading is 3C. The water is 4c and when you touch the pan (through the water) its 3c. The top of the pan is 5C
- Going to add beads to the water pan now and let it recool. Added about 10% less beads than the first one, letting it recool (initial check, the mix is at 9C)
- Update: the reading is 7 and the mix is about 9
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