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Year 7 Science — Light, shadows and reflection

Tell luminous objects from non-luminous, use the straight-line rule to explain shadows, and give the four properties of an image in a plane mirror.

Name: ________________________

Before you start

A torch, an opaque object and a screen — the three parts of a shadow set-up.

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  1. 1. Torch
  2. 2. Object
  3. 3. Screen
  4. 4. Shadow

Take away any one of the three and there is nothing to see: no light, no object to block it, or no surface for the dark patch to land on. In everyday life a wall, a floor or the ground plays the part of the screen.

  1. 1.Raise your left hand at a plane mirror and the image seems to raise its right. This perceived left-right swap has a two-word name. What is it?

  2. 2.Why does a kaleidoscope show so many different patterns?

    • a) The tracing paper at the end scatters the light into new colours
    • b) Its three mirrors reflect each other's reflections, and turning it rearranges the pieces
    • c) Its single mirror flips the pattern each time it is turned
    • d) The coloured pieces inside change colour as the tube warms

  3. 3.Why is the word AMBULANCE painted reversed across the front of an ambulance?

    • a) So that it looks different from ordinary vehicle lettering
    • b) So that it reads the right way round in the rear-view mirror of the vehicle ahead
    • c) So that it can be read from a great distance
    • d) So that it stays readable when the ambulance is moving fast

  4. 4.A red ball and a blue ball of the same shape are held in the same place in front of a torch. What can you say about their shadows?

    • a) The red ball casts the darker shadow, because red is the deeper colour
    • b) One shadow is reddish and the other bluish
    • c) The blue ball casts no shadow, because blue lets light through
    • d) Both shadows are the same, because changing an object's colour does not change its shadow's colour

  5. 5.What three things do you need in order to see a shadow?

    • a) Sunlight, a coloured object, and a dark room
    • b) A source of light, an opaque object, and a screen
    • c) A mirror, an opaque object, and a screen
    • d) A source of light, a transparent object, and a mirror

  6. 6.Sort each of these by whether it gives out light of its own.

    Groups: Luminous · Non-luminous

    • The Pole Star
    • The Moon
    • A firefly
    • Lightning
    • A mirror
    • The Sun

  7. 7.Why do we see the Moon at night, given that it is a non-luminous object?

    • a) It is lit by the lights of the Earth below it
    • b) It gives out a faint light of its own, weaker than a star's
    • c) It reflects the light the Sun casts on it
    • d) It glows from the heat stored in its rocks

  8. 8.A candle flame shines through a pinhole in a card onto a screen behind it. What does the image look like?

    • a) Upside down
    • b) The right way up
    • c) Too faint to have a shape
    • d) Left and right swapped, but the right way up

Answer key — Year 7 Science — Light, shadows and reflection

  1. 1. lateral inversion
  2. 2. b) Its three mirrors reflect each other's reflections, and turning it rearranges the pieces
  3. 3. b) So that it reads the right way round in the rear-view mirror of the vehicle ahead
  4. 4. d) Both shadows are the same, because changing an object's colour does not change its shadow's colour
  5. 5. b) A source of light, an opaque object, and a screen
  6. 6. The Sun → Luminous; The Pole Star → Luminous; Lightning → Luminous; A firefly → Luminous; The Moon → Non-luminous; A mirror → Non-luminous
  7. 7. c) It reflects the light the Sun casts on it
  8. 8. a) Upside down