Light and Sound Sources: Year 1 Study Guide
Light and sound are all around us. We can see and hear them because they travel to our eyes and ears.
A light source gives out light. The Sun is our main natural source. Others include fire, glow-worms, torches and lamps. The Moon is not a light source because it reflects the Sun's light. A sound source makes sound, from a bird calling to a drum being hit.
Sound is made when something vibrates. Hold a ruler over the edge of a desk and twang it: you see it vibrate and hear the sound. When it stops moving, the sound stops.
Sources of light and sound
| Light sources | Sound sources |
|---|---|
| The Sun | A guitar string |
| A torch | A bell |
| A candle flame | A voice |
| A glow-worm | A cicada |
Shadows
A shadow forms when an object blocks light. Opaque objects, such as wood or a book, make dark shadows. Transparent objects, like clear glass, let light through. Shadows change in size depending on how close the light is. Outdoors, shadows are longest in the morning and afternoon and shortest around midday in summer.
Shine it at a wall.
Is the shadow dark?
What happens to the shadow?
Label opaque and transparent.
Staying safe with light and sound
Never look straight at the Sun, even with sunglasses. Do not shine torches or lasers into anyone's eyes. Loud sounds can damage hearing, so keep headphone volume low and protect your ears at concerts. Wear a hat and sunscreen in bright Australian sunshine.
Worked examples and common mistakes
Example: Is the Moon a light source? No, it only reflects sunlight. Example: What happens if you pluck a guitar string and then hold it still? The sound stops, since vibrations stop. Common mistakes: thinking a mirror or the Moon makes light, and thinking you see because your eyes shine. We see because light enters our eyes.
Check your understanding: model answers
1. Light: the Sun, a torch. Sound: a bell, a voice. 2. An opaque object blocks the light. 3. You can feel it with your finger, or see rice grains jump on the skin.
✨ Key Takeaways
- A light source gives out light.
- Vibrations make sound.
- Opaque objects make shadows.
- Keep eyes and ears safe.
💬 Questions for Discussion & Reflection
- Name two light sources and two sound sources.
- What makes a shadow?
- How can you tell a drum is vibrating?
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