Students will calculate the relationship between the apparent brightness of a luminous object and the distance to the object.

• Activities included

Your students can now determine the luminosity of the sun using a 200 W light bulb. Using a null photometer constructed from paraffin and aluminum foil, a student can compare two light sources to determine the luminosity of or the distance to one of the sources. The photometer is then used to compare a 200 W light bulb with the sun to estimate the sun’s luminosity.

The kit also contains a 1' length of 0.01" optical fiber that, when taped to a flashlight, becomes an 'artificial star'. With an output of one-millionth of a watt, this small source of light is compared to a star in the sky and the distance to the star can be estimated.