THE SHAPE OF THE RAINBOW

Rainbows are spectacular rays of colour.

We can normally see them in the shape of arc.

But in fact, rainbows are in the shape of a circle.

We can’t see the whole circle because the horizon gets in the way and allows us to see only a half of the rainbow.

High in the sky, for example if you travel by the plane, you can sometimes see a full rainbow circle.

If you stand high in the mountains, you can sometimes see a full rainbow circle in a valley.

You can also try an experiment with a garden hose to see the full rainbow circle. The sun must be behind you and water droplets in front of you.

The centre of the rainbow is called the anti-solar point.It is the shadow of your head when you stand between the sun and the rainbow.

We can see coloured light only from raindrops that are at the proper angle from you and the sun. It is 40-42 degrees.

If we draw a shape between those raindrops,it will be an arc or a circle.

So, the rainbow is a circle aroundthe anti-solar point.

When the sun is lower, the rainbow is higher.

And when the sun is higher, the rainbow is lower.

Sometimes you can see an upside-down rainbow.

It happens when the sunlight is bent in ice crystals instead of raindrops.

By class 5

Základní škola, Kroměříž, Komenského nám. 440