# Lesson Plan: Stars Relative Distance

Subject:  Science

Lesson Objective: To understand and contend that the brightness of stars is dependent on their distance from Earth

Next Gen Science Standard:  5-ESS1-1. Support an argument that differences in the apparent brightness of the sun compared to other stars is due to their relative distances from Earth.

Materials:

• 2 flashlights

Starter:

Say:

• Why do you think the sun looks so bright in the sky?  (Allow the students to answer.)

Main:

Say:

• The sun looks so bright in our sky because we are close to it.
• Earth is about 92 million miles away from the sun.  This sounds like it is incredibly far away, and it is.  But, there are other things that are much farther away from Earth.
• The sun is the closest star to Earth.  The next closest star to Earth, Proxima Centauri, is 4.2 light years away. Each light year is about 5.8 trillion miles.
• The farther away from Earth a star is, the fainter it looks in the sky.  I am going to demonstrate this with 2 flashlights.
• Everyone please get up and go stand by the board.  (Place one flashlight that is turned on, very close to where the students are standing.  Place one flashlight that is turned on, as far away from the students as you can.)
• What do you notice about the two lights?  (Allow the students to answer.)
• The light that is closer to you looks brighter.  The light that is farther away from you looks fainter.  That is just how it is with stars and Earth.
• Most stars that we can see are so far away from Earth that we would never be able to travel to them.
• Now, you are going to pretend that someone is trying to convince you that some stars are brighter than others and it doesn’t matter how far away from Earth they are.
• Think about what you would say to them and how you would try to convince them that the distance between the stars and Earth are what makes some stars look brighter than others.
• You are going to write down what your response to that person would be.
• Does anyone have any questions?

Feedback:

Say:

• Who would like to share what you wrote?  (Allow the students to share.)

Written by Kimberly Greacen, Education World® Contributing Writer

Kimberly is an educator with extensive experience in curriculum writing and developing instructional materials to align with Common Core State Standards and Bloom's Taxonomy.