Thermocouple

__Creating a Thermocouple__

How are we able to find out how much we actually change the temperature of the sample when we shoot it with the laser? The original method of calculating the temperature change was by using rigorous mathematical calculations that were done by hand. In order to more accurately calculate the temperature change Dr. Kandel had the idea to create a thermocouple. One of the thermocouple wires needed to be made of some random metal; it had to be a metal other than gold so that we could measure a change in voltage when we attached the two tips to the surface of the gold. One wire was to be made of gold so that we could attach it to the gold surface with indium solder. By doing this we could use the entire surface of the gold as one of the two thermocouple metals. By attaching the gold wire with some indium solder we could then just touch the other wire anywhere on the surface of the gold and we would get a reading on the change of voltage which corresponds to a certain change in temperature. We chose to make the other thermocouple wire out of platinum. We chose platinum because we looked online and found that gold-platinum thermocouples have been used before and calibration charts already existed. I had taken readings at several temperatures (in ice, at room temperature, in boiling water, and in an oven at 63 degrees Celsius) and all that was left to do was to do some math and calculate a calibration curve. My work with the thermocouple ended when I was able to get the maximum amount of expansion for the gold when I shot it with the laser (they encouraged me to try taking more before and after images rather than to finish making the thermocouple).

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