A hands-on science lab · age 9

The Magic
Light Box

How does a camera catch light? Build it yourself — 6 missions, 1 badge.

Start
Psst… it's pitch black in here. Tap the lamp!
Mission 1
Turn the lamp on. Now slide your finger — you're the eye catching a ray!

Everything scatters light

The lamp emits light. The rocket scatters it everywhere. Slide your finger to catch a ray!

🔆 lamp emits rays🚀 object scatters rays👁️ eye catches a ray
…then slide your finger!

How does light reach your eye?

💡Aha!

Only lamps & the Sun emit light. Everything else — Moon, cats, YOU — scatters it. Seeing = catching scattered rays.

Mission 2
The oldest camera = a box with one tiny hole. Play with hole size, depth, then snap in a lens!

The box with one tiny hole

Light goes straight. One point on the rocket → one point on the wall. The picture flips upside down!

objectstraight rayspinhole or lensinverted image on sensor
Aperture (hole size)
pinholewide hole
Image distance (box depth)
closefar

Try it yourself

1) When the aperture gets BIG, the image gets…

2) Look at the sensor. The rocket's flame is pointing…

💡Aha!

Tiny hole = sharp, dim. Big hole = bright, blurry. A lens does both: bright AND sharp!

Mission 3
Slide the sensor until all rays from one dot meet again. That's focus!

The lens refracts light back together

Follow the red dot. Rays bend through the lens and must meet again on the sensor. Slide until they do!

one object dotrefracted raysfocus: rays meetblur: circles of confusion
Move the sensor (film plane)
near lensfar from lens
Focus

💡Aha!

Lens: one object point → one image point. Miss the focal plane? Points smear into blur circles. Real cameras auto-focus!

Mission 4
The sensor = tiny light-buckets. Pour light in, read the numbers!

A photo is a grid of numbers

96 light-buckets. Each stores a number 0–9. A photo = a grid of numbers!

photositescollect lightstore numbersRGB filters

👆 Tap a pixel to fill it yourself.

Pixel detective

💡Aha!

96 numbers here → 12,000,000 in a phone! Each pixel has a tiny red, green or blue filter. The camera stores numbers; your screen reads them back as light.

Be a pixel: mix the colour!

Red Green Blue
your mix →
← target

Each pixel has a tiny R, G or B filter. Mix them = every colour you've ever seen!

Mission 5
Freeze the ball 3 times! Too slow = blur. Too fast = dark. Find the sweet spot.

The shutter that freezes motion

The shutter opens, light hits the sensor, shutter closes. A moving ball leaves a streak if the shutter stays open too long!

shutter timeaperturemotion blurexposure = time × aperture × light
Shutter time: 1/250 s
very fastlong exposure
Aperture (light hole in lens)
small holelarge hole

💡Aha!

Short shutter = freeze, but dark. Wide aperture = bright, but blurry at close focus. Real cameras balance all three: time × aperture × ISO.

Mission 6
6 steps from light to file. Tap them in order!

Build the imaging chain

💡You said the whole secret!

Light → lens/pinhole → inverted image → pixels → shutter → file. That's every camera ever made.

Final
Five quick ones. Get them all and the badge is yours.

Question 1 of 5 · score 0

…

…

…

🏅
You did it. You built a camera out of light and numbers. What's your name, explorer?

Official

Explorer
Light-Box Builder · 0/5 on the quiz · 0 mission stars
"I know how a camera catches light."

Your word bag

🏠 Build one tonight

  1. Get a shoebox + grown-up help.
  2. Tape foil over one end. Poke one pin-prick hole.
  3. Tape wax paper on the other end = your screen.
  4. Dark room. Point the hole at a bright window.
  5. Look! The window is upside down on the paper. You made a camera obscura!
⚠️ Never point a pinhole or a camera lens at the Sun. Sunlight in a box gets very hot, very fast.