Table of Contents

Dr. Seahorse Creates Rainbows

Dr. Seahorse Creates Rainbows

Brief Description

Autumn is the season of colours: red, yellow and orange leaves are falling from the trees. And in the sky, rainbows! You can make them at home. Have a look!

Materials

A shallow bucket (or watertight pastry mould)

A small flat mirror

A sheet of white paper

Sunshine

Learning Objectives

Sunlight consists of many different colours.

Background Information

Although sunlight seems to be white, it actually is not. It consists of all kinds of colours that together form the colour ‘white’. These colours are unravelled by the water between the mirror and the surface. When a beam of light travels from the air to the water, it bends a little (‘refraction’). It bends even more when it travels back from the water to the air. Some colours bend more than others. Therefore, different colours reach the paper at different positions. The order of the colours of ‘broken white light’ is always the same. This is called the ‘colour spectrum’. You can see the colour spectrum in a rainbow: red, orange, yellow, green, blue, indigo (purple/blue) and violet. Rainbows that you see in the sky are formed by drops of rain that bend sunlight.

Step 1

Fill the bucket with water.

Step 2

Make sure the sunlight falls on the water by putting it near a window or outside.

Step 3

Lay one side of the mirror on the bottom of the bucket and the other against the side of the bucket. The reflective side should be pointing upwards.

Step 4

Now hold the sheet of white paper in front of the mirror at a small distance so it catches the sunlight that is reflected by the mirror.

Step 5

Move the mirror a bit with your free hand so it reflects the sunlight towards the paper sheet. Make sure that the mirror still touches the bottom of the bucket. Do you see what happens on the sheet of paper? (Image 1)

Keywords

Sunlight Colours Refraction Colour spectrum Rainbow

Source

NRC Handelsblad (3 November 2011)

License by-sa