Lesson Plan: Redshift Physics
This lesson plan includes the objectives, prerequisites, and exclusions of the lesson teaching students how to calculate the radial velocity of a star or galaxy using the amount by which absorption lines in the spectrum of light emitted from it are shifted.
Objectives
Students will be able to
- understand that if a galaxy is moving very fast away from Earth, the light emitted from it will be redshifted,
- understand that if a galaxy is moving very fast toward Earth, the light emitted from it will be blueshifted,
- understand that we can measure the redshift of a galaxy by looking at the positions of emission or absorption lines in its spectrum,
- recognize spectral line patterns in an emission or absorption spectrum and determine whether they have been redshifted or blueshifted,
- determine, based on spectral lines in an emission or absorption spectrum, whether a galaxy is moving away from or toward Earth,
- use in all permutations,
- use in all permutations,
- use in all permutations.
Prerequisites
Students should already be familiar with
- the idea that light is a wave,
- the idea that visible light is a part of the electromagnetic spectrum,
- the basic structure of the solar system, the galaxy, and the universe.
Exclusions
Students will not cover
- gravitational redshift,
- the difference between cosmological redshift and redshift due to proper motion,
- the Doppler effect as applied to waves in a medium.
