Have you ever wondered what a galaxy is? Or what was the Big Bang? Is it possible that life might exist on other planets? These are some of the big questions that researchers from our Institute of Cosmology and Gravitation are trying to answer. Astronomers take the laws of physics that work here on Earth, and use them to understand more about stars, galaxies and even the entire Universe

On this page, take part in a range of interactive activities, including:

  • Learn about Spectroscopy and make your own Spectroscope using just a CD and some cardboard
  • Discover all about light absorption and have a go at matching some elements to create light spectra
  • Test your knowledge as you go with short quizzes

ICG - Introduction to Cosmology

Staff from the Institute of Cosmology and Gravitation, introduce the taster session for the Virtual Summer School.

Light and spectra

Learn more about the visible light spectrum, refraction and diffraction in the video below - and then test your knowledge in a short quiz and have a go at making your own light spectroscope at home!

ICG - Light and Spectra

This short video provides an overview of the light spectrum and how you can make your own light scope at home.

Before you move on, test your knowledge from the video above by answering these multiple choice questions on light and spectra.

Make your own Spectroscope

As explained in the video above, a spectroscope is a device that splits up light into its different components so that you can see the spectrum.

There are a few different ways that you can make a basic spectroscope using a CD and items you have around the house - an empty cereal box, a kitchen roll tube or a piece of dark paper or card.

We think one of the easiest ways to do this is with an empty cereal box. Following the instructions you can download from your Virtual Attendee Hub, you should end up with something that looks a bit like this (don’t worry if it doesn’t look exactly like this, experiment with a design that works best for you!)

Using your CD spectroscope to view spectra

Once you’ve made your CD spectroscope then you’re ready to see some spectra! Point the slit at a source of light and look through the viewing hole. You should see a spectrum. You might need to experiment with how far in the CD is, and the width of the slit to make your CD spectroscope work well.

Take a look at different light sources around you, here’s some examples:

  • different light bulbs
  • a candle
  • a TV (switched on!)
  • a streetlight.

Make sure you don’t point the slit at the Sun (you could permanently damage your eyesight), but instead you can look at a piece of white paper outside during daylight. How many different spectra can you see?


Photographing spectra

You can use your smartphone to take photos of the spectra through your spectroscope. Hold the phone camera lens up to the viewing hole and take a photo. You might need to make the hole a bit better for the camera to work well.

Share your work

Share your spectra photography skills with us by scanning the QR code and uploading your photos!

Spectra in astronomy

In a similar way to how you'll have seen different spectra from different light sources, different objects in space have different spectra as well. This is usually to do with the chemical elements that they are made from.

This next video explains more about why we see different spectra and how they are used by Astronomers to identify whether there may be life on other planets or asteroids in space.

ICG - Using Spectra in Astronomy

Dr Jen Gupta demonstrates how Spectra is used in Astronomy, and asks how it can be used to determine the likelihood of life on distant planets.

Before you move on, test your knowledge from the video above by answering these multiple choice questions on spectra in astronomy.

Absorption spectra activity

We’ve provided the absorption spectra for two planets and the emission spectra for some known elements. Can you work out which planet is most likely to harbour life, based on the elements that are present?

Hint: Think about which elements are present in the earth's atmosphere as this is the only place we know life exists for certain.

Learn how ICG researchers are using spectra to understand the Universe

In the previous activity you’ve seen just one of the many ways that astronomers can use spectra to study distant objects and learn more about the Universe. Here are just some of the other ways that researchers at our Institute of Cosmology and Gravitation are using spectra in their work.

Find out more about Cosmology and related courses

BSc (Hons) Physics

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MMath/BSc (Hons) Mathematics

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BSc (Hons)/MPhys (Hons) Physics, astrophysics and cosmology

Read more