See-through
Clear glass lets the light straight through, so you see what is behind it sharply.
See through Lets the light pass, so you can see what is behind.
Step 1: Something to Notice
Watch first. The explanation comes later.
A window lets you see the garden. Bathroom glass lets the light in but you cannot see who is outside. A wall does neither.
All three are in the way of the light. Why are they so different?
Step 2: Find Out
Keep the lamp bright. Change only what is standing in the way.
Step 1 — Predict
A solid block is put in the way. How much light reaches the toy?
Choose what you think will happen. You cannot see the experiment until you do — guessing first is what makes it worth watching.
Step 3: So Here Is Why
Now the explanation, after you have seen it happen.
Cloudy
Frosted glass lets light through but jumbles it on the way, so you see a blur.
Blocked
A wall lets none through. You see nothing behind it, and there is a shadow.
Step 4: A Common Mistake
Lots of people think
“Things are either see-through or they are not.”
Step 5: Windows and Curtains
The same idea somewhere new.
A window is see-through. A thin curtain is cloudy — it lets light in but you cannot see out properly. A thick curtain blocks it.
Step 6: Think It Through
Practice makes it stick.
The Window
Problem 1 of 1
You want to see the garden from inside. Which one do you want in the wall?
What Gets Through?
1 of 3
Which one lets no light through at all?
2 of 3
Which one lets a bit of light through, but not all of it?
3 of 3
Put each one in order, from most light through to least.
- 1
- 2
- 3
Step 7: Quick Check
Show what you know.
Question 1 of 1
Which one is cloudy — some light through, but not enough to see properly?
What You Found Out
- See through: nearly all the light gets past.
- Cloudy: some gets past, but not enough to see properly.
- Blocked: none gets past.
For the grown-up
Three ways light meets an object — Some things let nearly all the light through, like clear glass. Some let a little through, like frosted glass or thin paper. Some let none through, like a wall or your hand.
People pick on purpose — Windows are clear so light gets in. Bathroom glass is cloudy so light gets in and people cannot see through. Curtains block it all for sleeping. Each one is chosen for the job.
See-through — Clear glass and clean water let nearly all the light carry straight on through them. Nothing is stopped and nothing is scattered, so the light arrives at your eye still in order and you see what is on the other side sharply.
Cloudy — Frosted glass, thin paper and a net curtain let light through but knock it about on the way. The light gets in, so the room is bright — but it arrives jumbled, so you see a blur and not a picture.
Blocked — A wall, a door, a thick curtain, your own hand: light hits them and none of it comes out the other side. Nothing gets past, so you see nothing behind them — and there is a shadow on the far side.