Waves, sound and light

On Mars, sound travels slower and fades faster, and the sunset glows blue. This topic starts with echoes and rainbows and climbs to wave speed, the spectrum of light, lenses and telescopes, and the instruments that read the rocks of Mars from a distance.

8 levels. The ages are only a rough guide for parents and teachers; anyone can start at any level.

Level	Rough age	What it covers
Level 1: Echoes and rainbows	5-6	Making sounds, hearing echoes, seeing colours
Level 2: Light and shadow	7-8	Light travels in straight lines, shadows, mirrors
Level 3: Vibrations	9-10	How sound is made and travels, pitch and loudness
Level 4: Sound on Mars	11-12	Why sound is quieter and slower on Mars (about 240 m/s, Earth's 343), what the rover microphones heard
Level 5: Wave speed	12-13	v = fλ, frequency, wavelength, reflection and refraction
Level 6: Light and colour	13-14	The spectrum, why the Martian sky is butterscotch and its sunset blue
Level 7: Lenses and telescopes	15-16	Focal length, magnification, seeing Mars from Earth and Earth from Mars
Level 8: Spectra	17 and beyond	Emission and absorption lines, how rovers read rocks with lasers