Build a machine that can lift marbles
Build a simple marble-lifting machine from cardboard, rubber bands, pulleys, and levers to lift and move marbles while exploring mechanical advantage and problem-solving.
About this activity
Build a simple marble-lifting machine from cardboard, rubber bands, pulleys, and levers to lift and move marbles while exploring mechanical advantage and problem-solving.
What you need
Step by step
- 1
Step 1
Gather all your materials and put them on a clear table so you can reach everything easily.
- 2
Step 2
Cut a cardboard base about 30 cm long and 15 cm wide to give your machine a sturdy floor.
- 3
Step 3
Cut two cardboard uprights about 10 cm tall and mark matching notches about 2 cm from the top of each upright.
- 4
Step 4
Stand the two uprights on the base about 10 cm apart and tape them upright so they do not wobble.
- 5
Step 5
Slide the pencil through the notches across the uprights to make a rotating axle that can turn like a pulley.
- 6
Step 6
Tie one end of a piece of string to the small cup or to the bottle cap so it becomes your marble bucket.
- 7
Step 7
Drape the loose string over the pencil axle so the cup hangs down on one side and the string hangs free on the other side.
- 8
Step 8
Cut a cardboard strip about 12 cm long to use as a lever and poke a paper fastener through its center.
- 9
Step 9
Push the paper fastener through the base near the hanging cup so the cardboard strip can pivot up and down like a seesaw.
- 10
Step 10
Position the lever so marbles rolled onto one end will tip them into the hanging cup when the lever lifts.
- 11
Step 11
Turn the pencil axle to wind the string and lift the cup to carry a marble upward and across to a new spot.
- 12
Step 12
Add or move rubber bands or change how many turns you wind to make lifting easier and notice how the machine’s effort changes.
- 13
Step 13
Take a photo or write a sentence about what you learned and share your finished marble-lifting machine on DIY.org
Fun facts
How do I build a simple marble-lifting machine with cardboard, rubber bands, pulleys, and levers?
Start by sketching a plan: decide whether to use a lever arm, a pulley lift, or a rubber-band winch. Cut a sturdy cardboard base and build vertical supports for axles (dowels or skewers). Mount a spool, straw, or washer as a pulley and attach string with a small scoop or cup to hold the marble. Add rubber bands for tension or to return the lever. Test, adjust pulley placement, string length, and friction until marbles lift smoothly.
What materials do I need to build a marble-lifting machine?
Gather cardboard (for base and supports), scissors or craft knife (adult use), ruler, pencil, glue or tape, rubber bands, string, wooden skewers or dowels, small spool or plastic bottle cap for a pulley, paper clips or brads, a small cup or folded cardboard scoop, marbles, and optional binder clips or clothespins for clamps. Have safety gloves and a cutting mat available; supervise any sharp-tool steps.
What ages is a marble-lifting machine activity suitable for?
This activity suits kids about 6–12 years old: younger children (4–5) can participate with heavy adult help for cutting and assembly, while older kids (10+) can design, iterate, and troubleshoot more independently. Supervise all ages when using scissors, knives, or small parts. Tailor complexity: simple lever or scoop for little ones, multi-pulley or gear experiments for older children.
What are the learning benefits and safety tips for making a marble-lifting machine?
Building this machine teaches basic physics (levers, pulleys, mechanical advantage), fine motor skills, planning, and problem-solving. It encourages trial-and-error and creativity. Safety tips: supervise cutting and small parts to avoid choking, use blunt tools for young children, secure moving parts to prevent pinches, and check rubber-band tension so bands don’t snap. Try variations like adding gears, ramps, or a battery motor for extended learning.
Watch & Learn
Need help?
What can we use instead of a pencil for the rotating axle if we don't have one?
Use a wooden dowel, straight chopstick, or sturdy skewer the same thickness as the pencil and slide it through the notches across the uprights to make the axle.
The cup won't lift or the string slips when I turn the pencil — what should I check?
Make sure the string is tied securely to the small cup or bottle cap, the pencil axle can rotate freely in the notches (remove excess tape), and add rubber bands or wind more turns around the axle as suggested to increase lifting force.
How can I adapt this activity for a 4-year-old or a 10-year-old?
For younger kids (around 4), pre-cut the cardboard base and uprights and pre-poke the notches so they can focus on tying the string and placing the cup, while older kids (10+) can redesign the lever length, change how many turns they wind, or add extra pulleys to explore mechanical advantage.
How can we make the marble-lifting machine more fun or challenging?
Decorate the cardboard base and cup, attach a cardboard ramp to carry marbles to a new spot, or add a counterweight and vary rubber bands or turns to measure how the machine’s effort changes.