Professor Picklebottom

The Magic Skewer

Imagine pushing a sharp wooden skewer through a bag full of water.

What would happen?

Most people expect a giant splash.

But this mystery bag has a surprise waiting.

Your challenge is to discover how many skewers it can survive before it finally bursts.

Make a prediction, collect evidence and look for clues as you investigate.

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MEET THE TEAM

Ages

5-12 yrs

Duration

min

10

Difficulty

Easy

Stage

Stage 2-3

Cite this resource

All Categories

Created by Darin Carr (BSc, DipEd)
NESA Accredited Teacher · Chemistry & Physics Specialist · 30+ years in-class teaching
Resource Version: 1.0
First Published:

Last Updated:

9 Apr 2019

18 July 2026

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The Magic Skewer

MISSION VERIFIED

Classroom tested. Teacher designed. Safe at home.

Practising NESA accredited

Australian Science Teacher

★ 30+ years of classroom experience

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Before you investigate... watch the mystery

MISSION HOOK

Professor Picklebottom and the team are travelling and collecting amazing science mysteries.

✔ Coming in Term 1 2027

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Mission Equipment

Gather your materials and get

ready for an amazing mission!

· 1 large zip lock bag (sandwich or freezer size)

· Water

· 3–5 wooden skewers (the pointier the better!)

· A tray or outdoor space — things WILL get wet!

Let’s Investigate

Follow the missions steps below to solve the mystery.

1 Prepare Your Challenge

Fill your zip-lock bag about ¾ full with water and seal it tightly.

Think Like A Scientist

How many skewers do you predict your bag will survive?

□ 1–3
□ 4–6
□ 7–9
□ 10+

PREDICT

OBSERVE

EVIDENCE

ASK

SAFETY

TIP

PREDICT

Gather your materials and get

ready for an amazing mission!

2 The First Test

Push one skewer carefully through one side of the bag and out the other side.

Watch Carefully

What happened?

□ Water leaked immediately

□ Only a few drops leaked

□ No water leaked

PREDICT

OBSERVE

EVIDENCE

ASK

SAFETY

TIP

PREDICT

Gather your materials and get

ready for an amazing mission!

3 Gather Evidence

Add a second skewer, then a third.

Keep counting.

Look For Patterns

As more skewers are added:

□ The bag still doesn’t leak

□ Small leaks begin to appear

□ The bag stretches

□ The bag feels weaker

PREDICT

OBSERVE

EVIDENCE

ASK

SAFETY

TIP

PREDICT

Gather your materials and get

ready for an amazing mission!

4 Find The Limit

Continue adding skewers one at a time.

Keep a careful count.

Data Question

How many skewers survived before the bag failed?

My result: ______ skewers

PREDICT

OBSERVE

EVIDENCE

ASK

SAFETY

TIP

PREDICT

Gather your materials and get

ready for an amazing mission!

5 Solve The Mystery

Observe what happens.

What happened?

□ The bag survived

□ Water leaked out

□ The bag burst

PREDICT

OBSERVE

EVIDENCE

ASK

SAFETY

TIP

PREDICT

Gather your materials and get

ready for an amazing mission!

1 Big Title

Every experiment follows The Crazy Scientist Lab Learning System™ — a simple way to help kids think like real scientists.

LINK to what they already know,
ACTIVATE curiosity through hands-on discovery
BUILD understanding that actually sticks.

You already know what happens when you poke a hole in a water-filled bag.

Water leaks out.

So why didn’t that happen this time?

Scientists often discover something surprising when an experiment doesn’t behave the way they expect.

This mystery starts with a simple question:

Why can a bag survive a skewer but not survive removing one?

As you pushed more skewers through the bag, you probably expected the leaks to get worse.

Instead, the opposite happened.

The bag kept holding water.

That tells us something important:

The skewer wasn’t simply making a hole.

Something else was happening around it.

Look closely at where the skewer enters the bag.

What do you notice?

Is water leaking around the skewer?
Does the plastic seem stretched?
What changes when the skewer is removed?

Scientists look for clues before jumping to conclusions.

Zip-lock bags are made from a material called polyethylene.

This material is made from millions of tiny flexible chains called polymers.

When a sharp skewer passes through the bag, it doesn’t cut the polymer chains apart like scissors.

Instead, many of the chains slide aside and stretch around the skewer.

The plastic grips tightly around the wood, creating a seal that stops most of the water escaping.

When the skewer is removed, that seal disappears.

The opening is now exposed and water can flow out.

That’s why a bag can survive many skewers—but often leaks the moment one is pulled out.

"Want the full teacher guide? The Crazy Scientist Lab includes classroom delivery tips, how to manage the WOW moment, differentiation for Stage 2 & 3, — ready to teach tomorrow."

Think Like a Scientist

Scientists don't stop after their first discovery.

They ask new questions, collect more evidence and test their ideas in different ways.

Where could you take this investigation next?

What happens if you push the skewer in slowly instead of quickly?

What happens if you use a thicker skewer — or try one that isn't as sharp?

Dr Puddledrip’s Science Tip

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Download. Print. Teach.

Read the Science

Why didn’t the water leak?

When you pushed the skewer through the bag, something surprising happened.

Instead of creating a large open hole, the plastic stretched tightly around the skewer.

This helped stop the water from escaping.

The bag could even survive several skewers before it finally failed.

Scientists Say…

Some plastics are made from long, flexible molecules that can stretch and move without breaking apart.

This is one reason the bag was able to hold water even after being pierced.

But that’s only part of the story…

Why did some bags survive more skewers than others?

Why does removing a skewer often cause a leak?

Would the same thing happen with a pencil, straw or metal rod?

Scientists keep asking questions long after an experiment is finished.

[The Water Balloon Timebomb] [Instant Snow]

Teachers & Homeschoolers: Print-ready HD versions of this Science Behind It poster and companion G&T Challenge Card are available inside The Crazy Scientist LAB.

Scientist's Challenge

Designed for HPGE, gifted learners and children who enjoy an extra challenge.

Teachers & Homeschoolers: Print-ready HD versions of this Science Behind It poster and companion G&T Challenge Card are available inside The Crazy Scientist LAB.

The Next Question...

You've solved today's mystery. Now discover where curiosity can take you next.

Teachers & Homeschoolers: Print-ready HD versions of this Science Behind It poster and companion G&T Challenge Card are available inside The Crazy Scientist LAB.

Vocabulary

Polymer

A material made from long chains of tiny particles that can bend, stretch, and change shape.

Flexible

Able to bend or stretch without breaking.

Variable

One thing that is changed during an investigation to see what effect it has.

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