I came in and worked on analyzing the data from Friday. I entered the heating and cooling data in Excel then plotted them on graphs. After that, I outlined a new piece of copper that would hold the new resistors that came in today. It was a 7.5 Ohm, 20 Watt resistor. After hooking it up to the power supply, I turned it on. The resistor got incredibly hot in 5 seconds. It was even hot enough to melt the lead solder. Matt suggested I add a second resistor in series. I did so then ran it again.The solder melted after about 30 seconds. The new power supply that Prof. Kandel ordered came in near the end of the day.
I outlined the places on the power supply box where Matt would drill holes so as to allow for enough room for the power supply inside it. I sanded the paint off around the holes that Matt drilled to allow for the box to be grounded electrically. I soldered the new resistors onto the new piece of copper that Matt cut for me because the other one was not well-shaped for a sample holder to screw into the back of it. This would prevent scanning because the resistors were too close to where the sample would be placed and would create too large of a physical distance that there would not be enough room inside the scope for it to scan. I also helped Jolae with scanning. I helped her get a feel for the scope and taught her how to better tell if a scan is bad.

I was not allowed to come in to the lab because the air filters were being cleaned and the lab was going to be filled with toxic gas.

I finished assembling the power supply box today. I spent most of the time soldering wires in their rightful place. Afterwards I tested the system. It got fairly hot to the touch. David was using the thermometer so I could not get a reading on actually how hot it was getting. It cooled fairly quickly and water did not boil on it.

I came in today and removed one of the resistors from the circuit so as to increase the temperature. I measured the temperature spike with the system on. I started it with the highest resistance capable by the potentiometer at 75 Ohm and a temperature of 23.5* C. There was no change in temperature. I checked the resistance between the two wires connecting the sample holder to the power supply and found that there was only a resistance of 1.0 Ohm. This was not even close to the 7.5 Ohm that the resistor was supposed to have. I moved the wires to the other resistor that was still on the sample holder. I checked the temperature again. I ran it and it did not change much at high resistance but melted the solder at the lowest resistance. The thermocouple was giving junk readings so Matt suggested I solder it down. The next time I ran it the solder melted and one of the wires came off. Then when I went to attach the wires, one of the leads broke off of the resistor. I tried using the other one that was still
on the sample holder but when I went to solder the wires, one of the leads on that resistor broke. I took a resistor from the sample holder we had used with the power supply we found in the lab yesterday. I soldered it to the current sample holder and attached the Ground and +V wires to the resistor. I reattached the thermocouple and
then turned it on. At about half the resistance, the temperature rose very slowly. AT about 1/4, it rose slightly quicker but still fairly slowly. I felt both the copper and the resistor and both were well over the 27* C reading that the thermocouple was giving. I took the thermocouple off and attached it with solder so it was connected to the resistor. I ran the system and it read the temperature at around 70* C. At this point, the solder began to melt which indicates clearly that the temperature reading was inaccurate. Matt cut the end then tried it again and it worked somewhat better. Our main problem now is that it doesn't heat or cool as fast as we would like.