Light & Sound — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. You can see clearly through clear glass.
Clear glass lets almost all light pass through, so you see well.
2. A material you can see right through is called transparent.
Transparent materials let light pass through with no blocking.
3. Wax paper lets a little light through, so it is translucent.
Translucent materials let some light through but you cannot see clearly.
4. A thick book blocks all light, so it is opaque.
Opaque materials stop light, so no light comes out the other side.
5. Sound can travel through air, water, and solids.
Sound needs matter to move, so solids, liquids, and gases all carry sound.
6. If you press your ear on a table, you hear taps better.
Sound travels faster through solid wood than through open air.
7. Sound cannot travel through empty space.
With no matter to shake, sound waves have nothing to travel through.
8. Tissue paper is thin and lets some light through.
Thin paper is translucent so a little light passes through it.
9. Light cannot pass through a door because the door is opaque.
Doors are made of solid wood or metal that blocks all light.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Window glass
→ Transparent
Transparent
Tissue paper
→ Translucent thin
Translucent thin
Thick book
→ Opaque solid
Opaque solid
Wax paper
→ Translucent waxy
Translucent waxy
Each material blocks a different amount of light based on how thick or clear it is.