This week's big question:
Why is the sky blue?
Although the light from the sun looks white, it's actually made up of all the colours of the rainbow. Light travels in waves and each colour of light has it's own wavelength - some colours have short waves, while others have long waves. When sunlight reaches Earth's atmosphere, it hits gas molecules and floating dust particles. This scatters the different colours. More short wave blue light is scattered towards our eyes than colours with longer wavelength, making the sky seem blue. Violet has an even shorter wavelength, so you'd expect the sky to look violet. However, human eyes are more sensitive to blue than violet, so we see a blue sky, not a violet one.