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Rulers of the Universe

This suite of three classroom activities is about distances in the Universe. Designed for grades 6-12, this group of activities provides a foundation for understanding how big and far away objects in the Universe are, as well as how astronomers have figured out these measurements. The three activities can all be done independently, and do not necessarily need to be done in a particular order. However, we recommend the following sequence: 

  1. Size and Scale of the Universe
  2. Parallax
  3. Inverse Square Law of Light

Size and Scale of the Universe
Size & Scale of the Universe 

The Universe is very, very big. One cannot reasonably create a scale model of the Universe that includes all of its components—from people to superclusters—and simultaneously scales their distances and sizes. This activity attempts to overcome that difficulty by examining the Universe at different realms.


Parallax Thumb
Parallax

One method that astronomers use to measure distances to far away objects is called parallax. This activity introduces students to the concept and has them make measurements of distance and parallax angle to determine their relationship. The activity can be done using a ruler, string, astronomical images and other items easily found in a classroom.

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Inverse Square Law of Light Thumb
The Inverse Square Law of Light

We all know that a light, such as a candle or a streetlight, looks dimmer the farther away from it we get. This classroom activity gives an easy way for students to measure the relationship between distance and brightness. Once students discover the relationship, they can begin to understand how astronomers use this knowledge to determine the distances to stars and far away galaxies.

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