WALA: How scientists measured and understood light

WALA: How scientists measured and understood light

L.O: to know that scientists have combined evidence with creative thinking to suggest new ideas and explanations for phenomena.

INTRODUCTION

Have you ever seen a rainbow?

What colours are in the rainbow?

What was weather like at that time?

Activity

Making a rainbow using glass prism

Materials

strong sunlight

Tools

glass prism

white cardboard / paper (optional)

adult supervision

What to do

1. Place a piece of white paper on the ground under the sunlight.

2. Put the prism on or above the paper.

3. Rotate and move the prism around until you see rainbow colors on the paper.

Explain how a rainbow forms.

ARISTOTLE

Aristotle was a greek scientist who lived in the forth century BCE.

He Thought Rainbows were caused by clouds reflecting sunlight at certain angles

IBN AL-HAYTHAM

He thought the rainbow was a reflection in a mirror. The cloud was like the mirror, with the sunlight reflecting off the cloud.

ISAAC NEWTON

He was the first English scientist to explain the rainbow accurately. He showed that sunlight is made up of different colours.

Newton used a prism to demonstrate that white light is a mix of colours.

When sunlight passes through a prism, it bends. This is refraction. The angle of bending is different for the various colours of light : red, orange, yellow, green, blue, indigo and violet.

In a rainbow, every raindrop acts as a tiny prism. The sun shines through the raindrops and light is refracted, giving a rainbow.

Conclusion

Go through the main points.