With Krea
How to build a robot that walks or rolls
To build a robot that rolls, tape two straws across the bottom of a small box, slide a wooden skewer through each straw as an axle, and push a bottle cap onto each end as a wheel. To build one that walks, fold a piece of card into a tent, cut a gap in each side to make four legs with round feet, tape a coin low inside each side, and tap it down a gentle ramp. In this course your kid sees how real robots get around on wheels, legs, or tracks, picks the right one for a job, builds a roller and a walker from recycling, and races them. Krea hosts four short films for kids 6 to 13, and your kid ends with two cardboard robots that move. Plan about 4 minutes of films and 45–60 minutes of building and racing. On Kubrio, all four films and the quiz are free, with no account.
All 4 lessons and the quiz are free on this page. Your kid doesn't need an account. See every lesson
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▶ 1:45 tourWhat your kid makes
Your kid ends with two robots made from recycling: a bottle-cap roller that rolls down a ramp and a folded-card walker that rocks and steps, plus a race that shows when wheels win and when legs do. Wheels, legs, or tracks is the first choice for any robot your kid designs later.
- Ages
- 6 to 13
- Time
- 4 films, about 4 minutes, then 45–60 minutes of building and racing
- You need
- A small box and two straws, two wooden skewers and four bottle caps, tape, a piece of card and two coins, a board and a few books for a ramp, and a towel, a grown-up for the skewers and the caps
- Host
- Krea
The 4 lessons
Lesson 1. Wheels, legs, tracks
Most robots on the ground get around on wheels, legs, or tracks: a rover rolls on six wheels, a robot dog walks on four legs, and a track is a long belt around the wheels.
- Hunt your home for things that roll
- Find three of them
- Draw them on paper
Where: At home
Lesson 2. Pick for the job
Engineers pick for the job: wheels are fast on flat floors, legs climb steps, and tracks cross sand, mud, and snow. Legs are hard to build, because a walking robot has to keep its balance, so most robots roll.
- Write a job for your robot
- Circle wheels, legs, or tracks
- Say why
Where: Paper
Lesson 3. Build a roller
Straws taped to a box hold skewer axles that spin, and bottle caps on the ends are the wheels.
- Tape two straws straight across the bottom of a small box
- Slide a skewer through each straw
- Have a grown-up poke the caps and snip the sharp tips, then push on the caps and roll it down a ramp
Where: At home
Lesson 4. Make a walker
A folded card tent with round feet and a coin low on each side rocks and steps down a gentle ramp.
- Fold card into a tent and cut a gap in each side for four legs
- Round off the feet and tape a coin low inside each side
- Race the walker against the roller on a smooth ramp, then on a bumpy towel
Where: At home
Take the quiz
Krea asks 3 questions about the films. Get 2 right and you finish the course.
Transcript
Lesson 1: Wheels, legs, tracks
Robots don't just stand still. They go places! But how do they get around?
Some robots roll on wheels. A rover on Mars rolls over rocks and dust on six wheels.
Some robots walk on legs. A robot dog steps over rocks and up the stairs on four legs.
And some ride on tracks. A track is a long belt around the wheels, like on a digger.
Wheels, legs, or tracks. Most robots on the ground use one of these three.
Look around you. A toy car rolls. A cat walks. A bike rolls. Things that move are everywhere.
Your turn. Hunt your home for wheels. Find three things that roll, and draw them on paper.
Lesson 2: Pick for the job
Engineers don't pick wheels or legs because they look cool. They pick for the job!
Wheels are fast and simple. On a flat floor, nothing beats them.
But wheels get stuck on steps. Legs can step up the stairs, and over toys on the floor.
Tracks spread the weight out, so they don't sink. They cross sand, mud, and snow.
Let's try it. Carry a snack across the kitchen? Wheels! Climb the stairs? Legs! Cross the sandbox? Tracks!
Legs are the hardest to build. With every step, the robot has to keep its balance. That's why most robots roll.
Your turn. Write a job for your robot on paper. Then circle wheels, legs, or tracks, and say why.
Lesson 3: Build a roller
Time to build! First, a robot that rolls. Everything comes from the recycling.
Get a small box, two straws, two wooden skewers, four bottle caps, and tape.
Tape the two straws across the bottom of the box. One at the front, one at the back. Keep them straight.
Slide a skewer through each straw. The skewer is the axle. The straw lets it spin.
Ask a grown-up to poke a hole in each cap, and snip the sharp tips. Push a cap onto each end.
Now test it. Put a book under a board to make a ramp. Let go. It rolls! If it wobbles, push the caps on straight.
Your turn. Build your roller, and send it down a ramp. How far does it go?
Lesson 4: Make a walker
Now the tricky one. A robot that walks! Walking is hard, so a little ramp will help.
Fold a piece of card in half, like a tent. That's your walker's body.
Cut a gap in the middle of each side. Now it has four legs. Round off the feet, like a rocking chair.
Tape a coin inside each side, low down. The weight keeps it from tipping over.
Set it at the top of a gentle ramp, and give it a tap. Rock, step. Rock, step. It walks!
Now race it against your roller. Who wins on the smooth ramp? Try a bumpy towel. Who wins now?
Your turn. Build a walker, and race it against your roller. You made robots that move!
Free guides to practise with
Questions parents ask
Are skewers safe for young kids?
The skewers are sharp, so the films hand the sharp jobs to a grown-up: poking a hole in each bottle cap and snipping the sharp tips off the skewers. Keep the coins and bottle caps away from children under 3.
What if the walker slides instead of walking?
Make the ramp gentler and give it another tap. The walker rocks from foot to foot, so a low slope, about one book high under a long board, works better than a steep one. Check that the coins sit low on each side.
Does this course need a robot kit?
No. Everything comes from the recycling: a small box, straws, skewers, bottle caps, card, tape, and two coins. The films play on this page, with no account.