The purpose of this lesson is to gain an
understanding of the techniques astronomers use to measures the distance
to and speed of distant stars and galaxies.
Students will explore the techniques astronomers use to measure the
distance to, composition of, and speed of distant stars and galaxies
through a series of hands-on activities using desktop light sources.
Students learn how to take and graph scientific data, and to interpret the
results. Students have the option of choosing from several differnet
Internet research project designed to allow further exploration of the
ideas contained in the hands-on activities.
- Inverse Square Law (Part 1)
- Students will measure the variation of the brightness of a
light with distance and compare their results to the inverse square law.
- Students will discuss the use of the inverse square law to measure
distance to a light.
- Light and Spectra (Part 2)
- By using a diffraction grating or spectrometer, students will
observe that light can be split into different wavelengths, which
correspond to different colors.
- Students will measure the wavelengths at which each of several
elements emit light.
- Students will demonstrate an understanding of the methods
astronomers use to measure the composition of distant stars and
galaxies by identifying some of the gases present in a fluorescent
- The Expanding Universe (Part 3)
- Students will explore the Doppler effect, which describes the
change in wavelength of the light emitted from a moving source.
- Students will understand that the Doppler effect can be used to
measure the speed of distant galaxies, and that the primary evidence
that the universe is expanding is that these galaxies are moving away
from the earth.
- Students will estimate the age of the universe by combining a
distance measurement using the inverse square law with a measurement
of the speed of the galaxy obtained using the Doppler effect.