Science corner

11th November 2005 at 00:00
Sophie Duncan explores refraction

Light travels in straight lines, but when it travels through different media it bends. This is called refraction. Here are ideas to help your pupils investigate how light travels through water, oil and air.

* Take a glass and half fill it with water. Put a pencil or ruler in the glass and look at it from different positions. Ask your pupils to record what they see. They should observe that the pencil appears bent. Light travels more slowly through water than through air. When the light enters or leaves the water it bends.

* Now add some oil to the glass, taking care to add it slowly so it forms a layer over the top of the water. Observe the pencil through the water and through the oil. Can your pupils work out whether light travels more quickly through oil or water?

* You can see refraction more clearly by making your own light-box. Take a shoe box and make a narrow vertical slit in one end. Place a torch so the light travels through the slit into the box. Dim the lights and observe where the light travels. Adjust the torch so the light travels straight through the box. Take a flat-sided glass jar and fill it almost to the top with water. Place it in the centre of the box and again observe the path of the light. Turn the jar of water at different angles and look what happens to the light.

* Once your pupils have experimented with refraction set them this challenge. Place a coin in a plastic bowl on a table. Ask one pupil to back away from the table and stop when they can no longer see the coin in the bottom of the bowl. Ask the class whether they can work out how the coin could be seen without moving the coin, the pupil or the bowl. Hopefully one of them will suggest adding water to the bowl. As you add water to the bowl the coin appears.

Log-in as an existing print or digital subscriber

Forgotten your subscriber ID?


To access this content and the full TES archive, subscribe now.

View subscriber offers


Get TES online and delivered to your door – for less than the price of a coffee

Save 33% off the cover price with this great subscription offer. Every copy delivered to your door by first-class post, plus full access to TES online and the TES app for just £1.90 per week.
Subscribers also enjoy a range of fantastic offers and benefits worth over £270:

  • Discounts off TES Institute courses
  • Access over 200,000 articles in the TES online archive
  • Free Tastecard membership worth £79.99
  • Discounts with Zipcar,, Virgin Wines and other partners
Order your low-cost subscription today