You’re going to be a science explorer!
Great job! You're learning important safety equipment words.
We use many transparent materials in homes, buildings and cars. Transparent materials allow us to see things.
Glass is a transparent material. Some glass is very strong. People are walking on glass on this bridge.

Transparent materials allow light to pass through them. We can see things clearly through them. Often transparent things protect our eyes or protect us from the weather.
Glasses and goggles help us to see clearly. They are made from transparent materials.

1. Why are dark sunglasses no help when we are indoors?

In some places the Sun is very bright. It would hurt your eyes badly. This snowboarder needs very dark goggles.
The goggles need to be a little opaque.
2. Why do the goggles need to be a little opaque?
3. Why should the goggles not be too opaque?
Think like a scientist
You will need: transparent coloured plastic, scissors, a flashlight
You can use more layers of coloured plastic to make even darker sunglasses.
Zara is testing the layers of coloured plastic to see how dark sunglasses could be.
She records the results like this:
| Layers of coloured plastic | How dark? | Notes |
|---|---|---|
| 1 | a little dark | This would be good on a sunny day. |
| 2 | darker | |
| 3 | ||
| 4 |
Predict which will be the darkest set of layers.
Now carry out tests on different numbers of layers of coloured plastic.
Was your prediction correct?
Record your results. Is there a pattern in the results?
Which would be make a good pair of sunglasses for a very bright day?
If you wore these at night, would you be able to see?
Why should you never look at the Sun, even when you are wearing sunglasses?
Complete this conclusion.
Every layer we add makes the sunglasses __________ .
Astronauts work in space where the Sun is very bright. They need a transparent material for their visors so that they can see.
But the visor needs also to stop the sunlight hurting the astronaut’s eyes. This astronaut’s visor is so dark we cannot see her face.
We can only see the reflection of her hands.

4. Why don’t astronauts wear sunglasses inside their helmet?
5. If you wore an astronaut’s visor in class, how would the room look?