Teaching overview

Learning points

  • Telescopes on the ground are limited to what they can observe in space, because gases in the Earth's atmosphere block their view.
  • SOFIA is a plane with a telescope attached to it, that can fly above Earth’s atmosphere and observe images that telescopes on the ground are unable to.

Curriculum keywords

  • Space
  • Solar System
  • Earth
  • Light
  • STEM

Spark a discussion

  • What objects are found in our solar system? How do we know they are there?
  • What is an astronomer? What skills do you think you would need to do that job?
  • What kind of instruments and technology do astronomers use to learn about space?
  • Why do we need to use telescopes when studying space?
  • Why do people want to learn about space? Is it important to discover more information about space?
  • What is SOFIA? How does SOFIA work?
  • Can you describe what SOFIA looks like inside and outside?
  • How is SOFIA different to other telescopes?
  • What advantages does SOFIA have over telescopes on Earth?
  • What advantages does SOFIA have over space telescopes?
  • Who works on-board SOFIA?
  • What information is SOFIA able to provide about space? How can SOFIA help with our discoveries about space?

Multimedia toolbox


Show this visual before the film and discuss what we know about space and how scientists gather information about the Universe.

Telescope images

Show this visual before the film and ask the children how they think these images of space were taken.

How do refracting telescopes work?

Show this visual after the film to help the class understand how a simple refracting telescope works.

A scientist who studies the Universe and the objects within it, such as stars and planets.
A scientist who studies the Universe and the objects within it, such as stars and planets.


Show this visual after the film to reinforce key scientific language.


Make a telescope

MAKE a refracting telescope to explore how lenses can make distant objects appear larger.

Open detailed instructions

Other activity ideas

  • RESEARCH different types of telescopes (e.g. radio, infrared, solar, optical) and make an information poster to display in the classroom.
  • DEMONSTRATE refraction by placing a pencil in a glass of water and noting how the pencil appears to “bend,” due to light waves changing direction when they pass between air, water and glass.
  • VISIT an observatory to see the equipment used by astronomers to observe the Universe.
  • DEBATE the importance of space observation and exploration with the class: is it useful and valuable, or a waste of money?
  • RECORD what is visible in the night sky every night for a week or month, and discuss any changes or patterns. What kind of factors affect visibility?
Print this sheet

Make a telescope

Duration: 60 minutes

Resources (per group):

  • 2 convex (magnifying) lenses of different sizes
  • 2 cardboard tubes of different sizes (so the smaller tube can fit inside the larger one)
  • Sticky tape
  • Coloured pens or paints
  • Scissors
  • How do telescopes work? visual (found in the Multimedia toolbox)

Key Learning:

This activity helps the children to understand that refracting telescopes use lenses to refract light and create magnified images.

  1. Organise the class into groups and hand out the resources. Tell them they are going to make simple telescopes.
  2. Discuss with the class what telescopes are and how they work. The purpose is to encourage children to draw upon their existing knowledge and share their ideas. They are not expected to accurately understand how a telescope works. You may want to ask the following prompt questions:
    • Why do people use telescopes?
    • Why can’t we see far away objects with the naked eye?
    • How do objects appear when you look at them through a telescope?
    • How do telescopes use light?
    • What are lenses? What do they do?
    • What happens to light when it passes through a lens?
  3. Explain that we struggle to see objects that are far away in space because our eyes are too small to gather enough light from the objects. The lenses in telescopes are much larger than the lenses in our eyes. This means they can gather more light from an object and produce a magnified image.
  4. Encourage the children to observe the effects of the magnifying lenses by looking through them individually and then together. Ask:
    • How do the lenses change the appearance of objects?
    • How does using one lens compare to using both lenses?
  5. Ask the children to paint the tubes and decorate them using the coloured pens or paints.
  6. Ask the children to place the larger magnifying lens at the end of the larger tube and secure in place using sticky tape.
  7. Ask the children to place the smaller magnifying lens at the end of the smaller tube.
  8. Insert the end of the smaller tube into the larger tube, so that the two lenses are at opposite ends.
  9. Encourage the children to look through the smaller lens and observe how the image changes when the smaller tube is moved in and out of the larger tube. Note: To produce a clear image, they will need to carefully adjust the length of the tube, which changes the distance between the two lenses. The clarity of the image will also depend on the distance between the telescope and the object that is being looked at.
  10. Display the How do telescopes work? visual (found in the Multimedia toolbox) on the whiteboard. Explain to the children that when they point their telescope at an object, light travels in a straight line from the object to the larger lens. The lens gathers and focuses the light, creating an upside-down image inside the tube. The second lens (called the eyepiece) then magnifies the image. This means that an object viewed through a telescope will appear larger than if viewed with the naked eye.

Explaining the science:

This type of telescope is called a refracting telescope. A real refracting telescope would use a different kind of lens to ensure the magnified image is the right way around when viewed. You may want to explain the difference between refracting and reflecting telescopes: Refracting telescopes use a lens to bend, or refract light before it reaches the eyepiece lens, whereas reflector telescopes use two mirrors to gather and reflect light into the eyepiece.

Background information

  • An astronomer is a scientist who studies the Universe and the objects within it, such as stars and planets. Astronomers use scientific equipment, including telescopes and satellites, to collect data that helps us to understand the Universe.
  • A telescope magnifies light from distant objects to produce larger and clearer images. Telescopes allow us to see amazing images of space and discover more about the objects that make up the Universe.
  • There are two types of optical telescope: reflector telescopes and refractor telescopes. Reflector telescopes use two mirrors to reflect light into a lens called the eyepiece. Refractor telescopes use a lens to bend, or refract light before it reaches the eyepiece.
  • Refraction is when light waves change direction as they pass from one medium to another. For example, light will bend when it passes from air into a denser material like glass or water.
  • SOFIA is an airborne observatory that observes astronomical objects including planets, comets, asteroid, stars, solar systems, galaxies and black holes. SOFIA is based on a Boeing 747SP and uses a variety of scientific instruments to gather data. SOFIA can make observations that are impossible for ground-based telescopes, because it is able to fly above the clouds and get a better view of space.


A scientist who studies the Universe and the objects within it, such as stars and planets.
When light bounces off a material.
The bending of light as it travels from one medium to another. When light travels from air into a denser material, such as water, it slows down and refraction occurs.
A curved piece of glass made of a transparent material that refracts (bends) light. Lenses can bend light to make things look bigger than they are.

Explore our resources

Complete your lesson with teaching resources on telescopes from Tigtag.

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Discover free online CPD for primary science from Reach Out CPD.

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