Matter and Electrons

Goal: To Measure emissivity from a light bulb and determine its blackbody properties.

Be sure that you play with the two student exercises so that you understand Planck's distribution formula.

Materials

• A Crooke's radiometer (can be purchased for under $10 )
• A Leslie's cube (commercial ones can be purchased for $10-25, epending on suppliers and quality. ). You can also make a substitute Leslie's cube using a square metal container, and painting one side matte black, one side shiny black, one side white, and leaving one side as shiny metal. It should be large enough to hold a small 40W lightbulb and socket. Make a "floor" and lid of aluminum foil to retain the heat, with a hole in the floor for the socket cord. Make a hole in the lid so that you can suspend a thermometer above the light bulb.
  

Procedure

1. Follow the instructions at Web Physics 320 Lab.

Data Handling

1. Use the data handling instructions with the lab procedures.

ALTERNATIVE LAB Goal: to observe changes in blackbody radiation at different temperatures.

Change the temperature of the blackbody and observe what happens to the emitted light.

Report

1. Describe your experiment in sufficient detail that another similarly equipped student could perform your tests.
2. Include your assessment that the light bulb acts/doesn't act as a blackbody over various temperature ranges.

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