Light, Shadows and Colour: Year 5 Study Guide
Light helps us see, and it behaves in predictable ways.
Light is a form of energy that travels in straight lines from a source. A luminous object (the Sun, a lamp, a candle) makes its own light. Other objects, like the Moon and a book, are seen because they reflect light into our eyes. Light travels very fast, about 300 000 kilometres per second, so it takes about eight minutes to reach us from the Sun.
Materials can be transparent (light passes through, like clear glass), translucent (some light passes through, like baking paper) or opaque (no light passes, like wood). An opaque object blocks light and makes a shadow.
Reflection and refraction
A smooth, shiny surface such as a mirror gives a clear reflection. A rough surface scatters light in all directions. When light passes from one material to another, such as from air to water, it changes direction. This is called refraction, and it is why a straw in a glass of water looks bent. Lenses use refraction to focus light in glasses, cameras and microscopes.
| Term | What happens | Example |
|---|---|---|
| Reflection | light bounces off | mirror, still pond |
| Absorption | light is taken in and becomes heat | dark clothes in sun |
| Refraction | light bends | straw in water, lens |
| Transmission | light passes through | window glass |
Shadows
A shadow forms when an opaque object blocks light. The shadow is longer when the light is low (morning and late afternoon) and shorter when the light is high. A shadow is also bigger when the object is closer to the light source. Shadow puppets use these ideas.
Torch or the Sun.
Between light and screen.
Move the object closer.
Shadow length.
Colour
White light is made of many colours, which can be seen when it passes through a prism or raindrops to make a rainbow: red, orange, yellow, green, blue, indigo and violet. A red object looks red because it reflects red light and absorbs most others. Never look directly at the Sun or shine lasers into eyes.
Worked example and common misconceptions
Example: To test which materials are opaque, shine a torch at each and see what reaches a screen. Common misconceptions: thinking we see because light comes from our eyes, that shadows are objects themselves and that mirrors make light. Fair tests change one variable and keep all else the same.
Check your understanding: model answers
1. For example, the Sun. 2. Light bends (refracts) when it moves from water to air. 3. Around midday, when the Sun is highest.
✨ Key Takeaways
- Light travels in straight lines.
- Opaque objects make shadows.
- Reflection bounces; refraction bends.
- White light contains many colours.
💬 Questions for Discussion & Reflection
- Name a luminous object.
- Why does a straw look bent in water?
- When is your shadow shortest?
Print a science experiment report →