STEM Challenges for Kids at Home: 10 Timed Challenge Cards

A good STEM challenge is simple: here is a goal, here is a small pile of materials and here is a timer. What happens next is the interesting part, as children plan, build, test, fail, tweak and try again.

These STEM challenges for kids at home need no special kit. Each of the ten cards below lists the materials, a suggested time and a clear success test so you can hand it over and step back. For the thinking behind this kind of play, see our article on STEM activities that build problem-solving skills.

How to run a STEM challenge in five steps

1. Read the card. State the goal, the materials, the time limit and the success test.
2. Plan (2 minutes). Ask your child to sketch or describe an idea before they build.
3. Build (the timed part). Let them work. Resist the urge to fix things for them.
4. Test. Check the success test together and measure or count if you can.
5. Improve. Ask “What would you change?” and let them have a second go.

Card 1: The tallest paper cup tower

• Materials: 20 paper cups (or any light cups)
• Time: 10 minutes
• Goal: Build the tallest freestanding tower.
• Success: It stands on its own for 10 seconds.
• Ask: Which shape is stable at the bottom? What happens when the base is wider?

Card 2: Index card bridge

• Materials: 2 stacks of books, 3 index cards (or paper strips), tape
• Time: 15 minutes
• Goal: Make a bridge between the stacks that can hold a small toy.
• Success: It holds the toy for 10 seconds.
• Ask: What happens when you fold or roll the paper? Which shape holds more?

Card 3: Foil boat

• Materials: a 15-centimetre (6-inch) square of aluminum foil, a tub of water, a handful of coins or washers
• Time: 15 minutes
• Goal: Shape a boat that floats and holds as many coins as possible.
• Success: The boat floats while holding the cargo. Count how many it can carry.
• Ask: How did a wider boat compare with a deeper one? Dry the floor afterwards and keep coins out of little mouths.

Card 4: Marshmallow and toothpick shapes

• Materials: mini marshmallows, toothpicks (or dry spaghetti for younger children)
• Time: 15 minutes
• Goal: Build the tallest structure or a shape with a triangle in it.
• Success: It stands without being held.
• Ask: Why do triangles seem stronger than squares? Use blunt sticks for little ones, and count toothpicks before and after.

Card 5: Paper airplane distance

• Materials: 3 sheets of paper, a measuring tape or a row of tiles
• Time: 10 minutes
• Goal: Make a plane that flies the farthest.
• Success: Measure three throws and write down the longest.
• Ask: What happened when you changed the wings or the nose? Throw away from people and pets.

Card 6: Cardboard marble run

• Materials: cardboard tube, paper plate, tape, a ball or large marble
• Time: 20 minutes
• Goal: Build a ramp that sends the ball into a cup.
• Success: The ball lands in the cup 3 times out of 5.
• Ask: What changes when the ramp is steeper? Use a large ball for children who might mouth small marbles.

Card 7: Spoon catapult

• Materials: a plastic spoon, a craft stick or pencil, rubber bands, a soft pom-pom or crumpled paper
• Time: 20 minutes
• Goal: Launch the pom-pom into a basket or onto a target.
• Success: Land in the target at least once.
• Ask: How do you change the distance? Aim away from faces and use only soft items.

Card 8: The strongest paper tower

• Materials: 5 sheets of paper, tape, a light book or a stack of small items
• Time: 15 minutes
• Goal: Build a paper column that can hold a book.
• Success: The book stays on top for 10 seconds.
• Ask: Is a rolled tube stronger than a flat folded piece? Why might that be?

Card 9: Toy parachute

• Materials: a plastic bag or cloth, string, a small toy or a soft ball, tape
• Time: 20 minutes
• Goal: Make a parachute that slows the toy as it drops.
• Success: The toy lands softly and takes longer to fall than a toy without a parachute. Time both drops.
• Ask: What happens if the parachute is bigger or smaller? Use a safe low height such as from a chair, with an adult watching.

Card 10: The longest paper chain from one sheet

• Materials: 1 sheet of paper, scissors, tape
• Time: 15 minutes
• Goal: Cut a single sheet into the longest chain you can.
• Success: Stretch the chain out and measure it.
• Ask: How could we make the strips thinner without them tearing? An adult should help with scissors for younger children.

Making challenges work for different ages

• Ages 4 to 5: Offer fewer materials, give a simpler goal such as “build something tall” and skip the strict timer. Focus on describing what they made.
• Ages 6 to 7: Use the cards as written, include a sketch step and let children count or measure results.
• Ages 8 and up: Add constraints such as a smaller budget of materials, ask for two designs to compare or have them record the results in a table.

Talking about the challenge afterwards

The conversation after the build is where the learning is.

• “What did you try first? What happened?”
• “What was the hardest part?”
• “What would you change next time?”
• “Which part of your design worked best?”

Praise effort and ideas rather than only the winning result, and let children see you try things that do not work too.

When things go wrong

• It falls apart. That is useful information. Ask what part was weakest and try a stronger base or extra tape.
• A child gets frustrated. Take a break, or reduce the goal slightly: “Can we get it to stand for 5 seconds first?”
• Siblings compete. Have them work together to beat their own record instead of each other’s.
• Not enough time. Set a longer timer or split the challenge into a design day and a build day.

From building to logic practice

Engineering challenges grow the same thinking skills that puzzles and logic activities do: planning, testing and trying again. If your child enjoys that side of things, Advanced Logic & Problem Solving: Skill Practice Workbook is a 15-page printable PDF for ages 6 to 7 with pattern, maze, sorting, sequence and observation activities. It is a paper workbook rather than a building kit, so it works well on days when you want a quieter activity. You will find more screen-free ideas in our guide to logic and problem-solving activities for kids and in our list of easy STEM activities using household items.

Quick materials checklist

Keep a “challenge box” ready so you can set one up in a minute:

• Paper cups, index cards, paper plates, plain paper
• Tape, rubber bands, string and a ruler
• Craft sticks, plastic spoons and cardboard tubes
• A timer and a notebook for recording results