Siege Engine Physics: Lesson Plans

Welcome & teams Share

1. Name tags and goggles for everyone. Make teams of 3 (mix ages and friends).
2. Each team picks a castle-y team name (the "Pumpkin Knights"?).
3. Quick question to the room: "What's the farthest you've ever thrown something?"

Story time: throwing things before gunpowder Share

1. Show pictures: a drawing from about 1230 and the real-size trebuchet at Dover Castle.
2. Tell it as a story: castles had thick walls, so engineers built giant machines that used a falling weight to throw rocks over them.
3. Demo: launch a ping-pong ball with the finished tabletop trebuchet. Ask: "What made it move? Nobody pushed it!"

Launch Rules drill Hands-on

1. Go through the five Launch Rules.
2. Practice the countdown as a whole class: "Lane clear?" → "Lane clear!" → "3, 2, 1, LAUNCH!"

Lever lab: the ruler seesaw Hands-on

1. Each team balances a ruler on a pencil (the fulcrum).
2. Put 3 washers on one end. How many washers balance it on the other end? Now move the pencil closer to one end and try again.
3. Flick test: put a pom-pom on the long end and tap the short end. Move the pencil. When does the pom-pom fly highest?
4. Kids record their best "flick" in their Launch Log.

Discovery we're after: a light tap on the short side makes the long side move fast. That's exactly how a trebuchet arm works.

Quick build: popsicle-stick catapult Hands-on

1. Stack 7 jumbo sticks and rubber-band both ends (the base).
2. Rubber-band 2 more sticks together at one end only (the arm), then slide the base between them.
3. Tape or rubber-band a plastic spoon to the top stick.
4. Launch pom-poms and ping-pong balls down the lane. Try moving the base stack closer to the rubber-banded end. Farther or shorter?
5. This one is theirs to take home on Launch Day, and it's our "cousin" machine: it stores energy by bending, not by lifting a weight.

Snack break Break

Trebuchet build, part 1: the frame Hands-on

1. Hand out a kit to each child (everyone builds their own, and teammates help each other).
2. Press or screw the two uprights into the base. Check that they stand straight with a "square" (the corner of an index card).
3. Slide the axle through the uprights and make sure it turns freely.
4. Write your name on the base and decorate it with markers or stickers (a coat of arms!).
5. Park the machines in the team bin.

Clean up & one cool thing Share

Every team says one cool thing they discovered today. Teaser: "Next week your trebuchets fly!"

Stored-energy demo Share

1. Hold a cup of washers low, then high. "Which one has more 'stored-up push'?" Drop both onto a pillow and compare the thump.
2. Show the energy picture below: lifted weight → falling weight → flying ball.

Trebuchet build, part 2: arm, counterweight & sling Hands-on

1. Arm: slide the arm onto the axle. The short end is for the counterweight, the long end for the sling. Check that it swings freely.
2. Counterweight bucket: hang a small cup from the short end with string or a paper clip.
3. Release pin: press the bent wire or 3D-printed pin into the tip of the long arm, angled slightly forward.
4. Sling: tie a 6″ string to each side of a felt pouch. Tie one string firmly to the arm tip. Make a small loop at the end of the other string; it slips over the release pin.
5. Trigger: hold the arm down with a finger (or a pencil through a hole in the frame). Letting go = launch.

Grown-up safety check Hands-on

An adult checks every machine: axle secure, arm swings freely, sling loop slips off the pin, goggles on. Then it gets a "✔ Ready to launch" sticker.

Snack break Break

First launches! Hands-on

1. Take the machines to the launch lanes. Start with 5 washers and a ping-pong ball.
2. Each child launches 3 times. Teammates spot where it lands and read the tape marks.
3. Record the distances in the Launch Log. Celebrate the first flights!
4. Troubleshooting: if it flies backward or straight up, the release pin needs bending (forward = later release, lower flight).

Experiment: how much counterweight? Hands-on

1. Make a prediction together: "If we double the washers, will it go twice as far?" Write the guesses on the paper tablecloth.
2. Each team tests 3, 5, 7, and 10 washers, with 2 launches each, keeping everything else the same (a fair test!).
3. Fill in the counterweight chart in the Launch Log (a simple bar chart with stickers works great).
4. Look for the "too much" point: does the machine tip, jump, or throw wildly?

Share & park Share

Each team shows its chart. Did doubling the weight double the distance? (Usually not quite, and that's a great puzzle.) Park the machines.

The fair-test trick Share

Mini-demo: change the counterweight and the ammo at the same time. "So which one made it go farther?" Nobody can tell! That's why engineers change one thing at a time. Today we tune three things, one at a time, at three stations.

Station A: sling length Hands-on

1. Keep the washers at your team's "best" number from last week.
2. Try slings of 4″, 6″, and 8″ (pre-cut strings with loops), with 2 launches each.
3. Record them in the Launch Log. Which sling length is the champion for your machine?

Discovery: a longer sling acts like a longer arm, so it's faster, up to a point. Too long and it drags on the table or lets go at the wrong time.

Station B: release angle Hands-on

1. Gently bend the release pin: straight up, a little forward, and more forward (adults help).
2. Watch the flight path: high rainbow or low line drive? Which goes farthest?
3. Use a protractor to measure the launch angle roughly (a partner can film in slow motion on a phone).

Snack break Break

Station C: ammo showdown Hands-on

1. Same machine and settings. Launch a pom-pom, a ping-pong ball, and a mini bean bag, twice each.
2. Rank them farthest to shortest in the Launch Log. Surprised? (Very light things get slowed by the air; heavier things need more "push" to get going.)

Target practice Hands-on

1. Set up a hula hoop, a bucket, and the paper bullseye box at different distances.
2. Teams choose their settings to hit each target. Can you predict where it will land before you launch?

Meet the cousins: catapult, slingshot, ballista Share Hands-on

1. Quick side-by-side launches: the popsicle-stick catapult (bending), a tabletop slingshot (stretching rubber band), and the trebuchet (falling weight).
2. Which is most powerful? Most accurate? Easiest to aim?

Lock in your Launch Day settings Share

Each team writes its "secret recipe" (washers, sling, pin) on a card and tapes it to the machine.

Pit crew: tune-up & practice Hands-on

1. Check the machines (axle, sling, pin), and fix or swap any worn parts.
2. Practice launches using your "secret recipe" card. Tweak one thing at a time.

Launch Day stations (teams rotate every 10 minutes) Hands-on

1. Farthest Flight: the best of 3 in the long lane, with a ping-pong ball.
2. Bullseye: 3 launches at the target box. The closest to the center counts.
3. Steady Eddie: 3 launches, and whose three land closest together?
4. Call Your Shot: pick a target, predict the landing spot, then launch a bean bag. Closest to your prediction wins.

Keep it friendly: cheer for every launch, and adults record results on a big poster.

Snack break Break

Big-machine demo Share

1. If space and weather allow (gym, playground, or a snowy field), the Berkshire Trebuchet Project team demonstrates a bigger trebuchet launching bean bags much farther.
2. Kids predict the distance first, using what they learned. Then launch!
3. Adults only operate the big machine. Kids watch from behind the line.

Show & Tell + Fun Awards Share

1. Each team shows its machine and shares one favorite discovery ("A longer sling made ours go way farther!").
2. Hand out fun awards, one for every child (see list), plus certificates.
3. Group photo with the machines (with parent permission).

Pack up & take home Share

Machines, catapults, Launch Logs, and the family note go home. Mention the Pumpkin Providing Partners program for families who want to keep going!