Lesson 11 of 12 · Momentum

Experiment⭐ 30 XP

Ballistic Pendulum

🧪Lab Brief #11

Ballistic Pendulum.

🎯 Your mission

Predict it first. Then prove yourself right (or wrong).

⚡ The twist

Nature loves to surprise the careful watcher.

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Mind = Blown

🔬 The more you look, the more nature shows you.

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Make a hypothesis first

Before you start: write down what you think will happen, and why.

What You'll Learn

Fire a projectile into a hanging block and it embeds, so momentum is conserved through the impact but kinetic energy is not. The block then swings, and energy conservation on the swing gives its speed — combining the two laws recovers the projectile's launch speed.

Key Words

Tap a word to see its definition.

Materials Needed

toy dart launcher
modelling clay
tub
string
metre rule

Safety First

Wear eye protection and never aim a launcher at a person.
Fire in a cleared area with a backstop behind the target.

Steps

Step 1 — Read

Read the explanation above and note the two key terms before you start.

Step 2 — Do

Fire a soft dart into a suspended tub of modelling clay and measure the height it rises. Use energy conservation on the swing to get the combined speed, then momentum conservation to find the dart's launch speed.

Step 3 — Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 — Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Check Your Understanding

Question 1

1 of 2

In a ballistic pendulum, momentum conservation applies to:

How sure are you going to be?😐 maybe

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Where you see this in real life

This shows up in your everyday life more than you'd think.

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Stretch Challenge

Try this in real life this week.

Try one experiment in real life this week — even a tiny one.

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For the dinner table

“What's the most surprising thing you learned today?”

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Next Smart Experiment

We'll pick an experiment that matches exactly how you're thinking right now.

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Share this experiment

Send it to a parent who's looking for a 10-minute kitchen science win.

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