Science

Question 1

What are we going to talk about?

Answer 1

Physics

Question 2

What is colour?

Answer 2

• The light that we see is made up of many different colours
• There are 3 primary colours: red, green and blue. They can be combined in different ways to make every other colour
• The colour of an object is determined by the wavelenght of light that is reflects

Question 3

Sunlight and colour

Answer 3

• White light from the sun is a mixture of colours
• You can use a prism to split white light into a spectrum of colours: red, orange, yellow, green, blue, indigo and violet
• Dispersed means that the colours are separated out
• We can see higher frequencies of light as blue or violet, lower frequencies of light are seen as red and orange. Green light is in the middle

Question 4

Eyes and colour

Answer 4

• Our eyes only detect three colours: red, green and blue
• By combining these colours however, we can perceive many other different colours
• For example, by mixing red light and green light, for example, we can see yellow light. If all three are mixed together we see white light
• Objects absorb and reflect light differently. A lemon reflects yellow light, all the other colours are absorbed and so aren´t seen by our eyes

Question 5

What are light waves?

Answer 5

• Light travels in waves
• Light waves travel in straight lines
• Light waves travel faster than sound waves

Question 6

How does light move?

Answer 6

• Light travels as waves
• Light waves don´t always need something to travel through. They can also travel through outer space or a vacuum
• Light waves travel in straight lines. You can detect them with your eyes, and also with instruments such as cameras. They are reflected by mirrors and change direction when they travel from the air into glass or water
• Light travels very fast. It has a speed of 300 million metres per second in a vacuum
• It only takes 8min and 20s for light to travel from the Sun to the Earth
• Light travels through the air about a million times faster than through sound, which explains why you see lightning before you hear the thunder

Question 7

Features of Waves

Answer 7

• Both water waves and light waves are undulations or ripples of energy that travel in a transverse motion
• Transverse waves

Question 8

Water Waves

Answer 8

• If you throw a pebble into a pond