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Engineering activity

Catapult Constructor

Build a simple catapult from a spoon and a block to launch pom-poms across the room!

BuildingAbout 25 minutesScreen-freeParent help expected

Materials and setup

How this changes by age

Pre-K (ages 3–4)

Build a simple catapult from a spoon and a block to launch pom-poms across the room!

Difficulty 1 of 3

Steps

  1. Place a block or small box on the table.
  2. Balance a plastic spoon on the edge of the block like a seesaw.
  3. Place a pom-pom or cotton ball in the spoon bowl.
  4. Push down on the handle end to launch the pom-pom!
  5. Experiment: what happens when you push harder? When you move the block?
  6. Set up a target (cup or box) and try to land the pom-pom inside.
  7. Tell a grown-up one thing that surprised you.

Learning objectives

  • Explore the lever as a simple machine
  • Observe how force and position affect launch distance
  • Practice aim and prediction

Kindergarten (ages 5–6)

Build a popsicle stick catapult that launches small objects. Experiment with different arm lengths and rubber band tensions.

Difficulty 2 of 3

Steps

  1. Stack 5 popsicle sticks and rubber-band both ends.
  2. Take 2 more sticks and rubber-band one end only.
  3. Slide the stack between the 2 sticks, near the banded end.
  4. Glue a bottle cap to the top stick as a launch basket.
  5. Load a pom-pom and launch! Measure how far it goes.
  6. Experiment: move the stack closer or farther from the launch end. What changes?
  7. Tell a grown-up one thing that surprised you.

Learning objectives

  • Build a lever-based launching mechanism
  • Observe how fulcrum position affects launch distance
  • Measure and compare distances

Early elementary (ages 6–8)

Engineer a catapult to hit a target at a specific distance. Test variables: arm length, rubber band count, and launch angle. Record data in a chart.

Difficulty 2 of 3

Steps

  1. Build a catapult from popsicle sticks, rubber bands, and a plastic spoon or bottle cap.
  2. Set up a target at 3 feet, 5 feet, and 8 feet.
  3. Test 1: Change arm length (fulcrum position). Record distance for each setting (3 tries each).
  4. Test 2: Change rubber band count (1, 2, 3 bands). Record distances.
  5. Test 3: Change launch angle by propping up the base. Record distances.
  6. Make a data table. Which variable had the biggest effect on distance?
  7. In one sentence, tell a parent or sibling what surprised you today.

Learning objectives

  • Conduct a controlled experiment changing one variable at a time
  • Record and analyze data in a table format
  • Identify which variable most affects projectile distance

Upper elementary (ages 8–10)

Design and optimize a catapult or trebuchet for maximum accuracy. Calculate launch angles, measure trajectories, and compare lever arm ratios.

Difficulty 3 of 3

Steps

  1. Research the difference between a catapult and trebuchet. Choose one to build.
  2. Design with labeled measurements. Calculate the lever arm ratio (effort arm : load arm).
  3. Build from wood craft sticks, dowels, rubber bands, and a counterweight (for trebuchet).
  4. Set up a target at 10 feet. Take 10 shots and record where each lands on a grid.
  5. Calculate accuracy: percentage of shots within 6 inches of target.
  6. Optimize: adjust lever ratio, counterweight, or angle. Take 10 more shots.
  7. Graph both data sets. Did your changes improve accuracy? By how much?
  8. In one sentence, tell a parent or sibling what surprised you today.

Learning objectives

  • Compare mechanical advantages of different siege engine designs
  • Calculate lever arm ratios and predict their effect on performance
  • Use statistical measures (accuracy percentage) to evaluate engineering changes

Safety and evidence note

Read the full activity before beginning. An adult should supervise tools, heat, food, outdoor work, movement, and experiments as appropriate. Completion records that the activity was done; the child’s explanation, work sample, photo, or demonstration is stronger evidence of learning than a completion check alone.

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