Astronomy 512 - Spring 2006 - Assignment 3
- Observing Thermal Contraction
On the conference table you will find two metal rods - one copper one aluminum.
Measure the thermal contraction [ (delta l)/l ] of each of these rods between
room temperature and 77K. Liquid nitorgen is available in the storage dewar in the lab. Recall the handling precautions.
- Cryogenic Thermal Modeling (in groups)
- a) Make a time dependent thermal model in which you coarsely integrate
the heat flow from a cryogenic reference surface held at 77K through
a simple one-inch diameter rod of 6061-T6 aluminum 3" long that is initially
isothermal at room temperature. This thermal model should be an individual
effort with significant within-group consulting.
- b) Use the liquid-nitrogen dewar in the lab to test this model.
Instrument your 3" part with two or more diode temperature
sensors. Record the temperature change vs. time following the
introduction of liquid nitrogen into the cryostat.
You may use the Lake Shore temperature reference already
installed to measure the temperature of the dewar work surface.
Due Wednesday March 15 (i.e. following Spring Break)