Expanded Galileo Telescope Activity

This OER was designed by the OU Academy of the Lynx (oulynx.org) in conjunction with the "Galileo's World" (galileo.ou.edu) exhibition at the University of Oklahoma.

This activity is an expanded activity on the Galileo Telescope. For adaptations to other age levels and pedagogical settings, visit the "Galileo Telescope Cluster" below.

Download: Activity Handout

Expanded Galileo Telescope Activity

Part 1 - Lens Activity

A telescope makes uses of both concave and convex lenses to magnify distant objects.

** The only supplies you will need for this activity are a set of concave and convex lenses. **

WarningWhen performing this experiment it is important not to look toward a window, whereby you might accidentally glance toward where the light might be blinding.

  1. Find the plano-convex lens. The plano side is flat. The convex side bulges. Look through the plano-convex lens at an object near by. Does it magnify it or make it smaller?
  2. Find the plano-concave lens.  The plano side is flat, and the concave side is indented. Look through the plano-concave lens at an object on the far side of the room. Does it magnify it or make it smaller?
  3. Position the two lenses in a line at eye-level, with the flat sides facing toward each other.  Try to focus on an object a few feet away.   Hold the plano-concave lens close to your eye, and the plano-convex lens a few inches farther away. Is the object right-side-up or up-side-down?

Part 2 - Galileoscope Activity

** A Galileoscope will be necessary for this activity **

WarningWhen performing this experiment it is important not to look toward a window, whereby you might accidentally glance toward where the light might be blinding.

Pick up the Galileoscope. The lenses of the Galileoscope are more powerful
and clear than those used by Galileo. Nevertheless, this telescope was designed to allow anyone to simulate Galileo’s discoveries.

Try to observe an object across the room.

  • Are objects right-side-up or up-side-down?

  • How difficult is it to observe a distant object?

  • How narrow is the field of view?

  • How steady is your grip?  

Enjoy a PDF of both activities combined together:

Download: Activity Handout

Historical Background to Galileo's Telescope

The earliest known telescope was created in the beginning of the seventeenth century by Hans Lippershey. This "spyglass," as it was originally called, was an instrument whose significance was originally understood in terms of sailing. The spyglass was useful for spotting other ships as well as land features from far away.

Galileo made the telescope famous. When Galileo heard news of the telescope invented in the Netherlands he worked out the underlying geometry and crafted one of his own design. In this work, Galileo produced the first published observations of the heavens made with a telescope. His sensational discoveries included mountains on the Moon, vast numbers of previously undetected stars and four satellites of Jupiter.

See high-quality images from Galileo's book here, https://galileo.ou.edu/exhibits/starry-messenger.

Further OER's on Galileo's Telescope

Use the following OER's to further explore Galileo's Telescope.

Use the following OER's to further explore the Galileo's World exhibition.

Galileo's Telescope Educational Cluster

We want to create variations on this activity that connect the Telescope to a variety of ages. Use the following chart and hyperlinks to find the one to best fit your group.

 Elementary SchoolMiddle SchoolHigh SchoolUndergraduate
Introductory Activity    
 30 Minute Activity 
 One Hour Activity    

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