A new machine every week
Open the box.
See how it moves.
Watch a 40-second short, then play with the machine yourself.
Week 2 · Force
A 40 kg crate hangs from a rope that runs round some wheels. Could you hold it up with a pull like 10 kg?
Pick a pulley. Lift the crate. Count the ropes.
Open PulleysDrag the orange pull arrow down to lift the crate, or tap any part to see what it does.
- Pull needed
- 98 N (like 10.0 kg)
- Crate rises
- 0.00 m
- Rope you pull
- 0.00 m
4 rope parts share the crate: a 1/4 of the pull, but 4 m of rope for every metre it rises.
12 machines, 12 weeks
- WEEK 1Force
The Lever
How a small weight lifts a heavy crate
Out now: play it - WEEK 2Force
Pulleys
How one person lifts a car engine
Out now: play it - WEEK 3Motion
Gears
Why your bicycle has different gears
Coming in week 3 - WEEK 4Force
Ramps and screws
How a ramp beats the stairs
Coming in week 4 - WEEK 5Force
Friction
Why car tyres have grooves
Coming in week 5 - WEEK 6Fluid
Hydraulics
How a tiny push lifts a car
Coming in week 6 - WEEK 7Fluid
Buoyancy
Why a steel ship floats
Coming in week 7 - WEEK 8Force
Centre of gravity
Why some toys always pop back up
Coming in week 8 - WEEK 9Motion
Spinning
Why a moving bike stays up
Coming in week 9 - WEEK 10Energy
Energy
Why the first hill is the highest
Coming in week 10 - WEEK 11Motion
Cranks and cams
Turning spinning into up and down
Coming in week 11 - WEEK 12Heat
The engine
Turning explosions into motion
Coming in week 12
Bonus
Machines in the wild
Famous real machines, built from the same ideas. Same short, same play-first page.
Bonus
Everyday machines
Small machines you own and use, opened up. A short, the answer, and one thing to play with.
- Motion Heavy or light pendulum Which swings faster, a heavy ball or a light one? Play it →
- Energy Newton's cradle Why does only one ball fly out? Play it →
- Motion The click pen How does it know to go in or out? Play it →
- Motion The ticking bike wheel Why does it tick when you stop pedalling? Play it →
- Fluid The toilet cistern How does it refill itself, and know when to stop? Play it →
- Motion The door lock Why does only your key open your door? Play it →
- Force The zipper How do two rows of teeth lock with one pull? Play it →
- Energy The tape measure Why does it stand out stiff, then snap back in? Play it →
- Motion The mechanical watch How does a spring keep time for two days? Play it →
- Heat The car engine How does a spark turn into a turning wheel? Play it →
- Heat The jet engine How does a jet engine push a plane? Play it →
- Force The combination lock How does a dial padlock know the right numbers? Play it →
- Heat The fridge How does a fridge make cold? Play it →
For the curious: posts only, no shorts
The Million-Dollar Problems
In 2000 the Clay Mathematics Institute put a $1 million prize on each of seven problems. One has been solved. Six are still open. Play with each one before you meet its equation.
See all sevenLearn the colour code
Same colour, same idea, in every video and on every page.
- Forcepushes, pulls, pressure, torque
- Energystored, moving, electric
- Motionspeed, spin, movement
- Heattemperature, heat flow
- Fluidwater, air, oil
Build it with your hands.
3D-printed kits of every machine are on the way. Grown-ups: get the next machine in your inbox and hear first.