Description: This demonstration gives a visual metric for how light intensity changes with distance
- Paraffin block photometer
- Clamp on light
- Light bulb
- VariAC to banana plug cable
- Clamp a light to the end of a table.
- Connect the light bulb to the VariAC.
- If a new photometer must be made, take two bars of paraffin was, place a piece of aluminum foil in between them and tie together with rubber bands.
- Turn on both lights.
- By holding the photometer so that each wax block is facing a light source, you can compare the intensity of the light from two sources.
- You may also vary the distance between sources and show that the intensity follows the inverse square law (use one light as a reference source).
- When finished, turn off both lights.
Note: Don’t place the Paraffin block photometer near any hot light sources, as the wax may melt.