Balloon Kebabs (Science Box Experiment 5)

As part of CoCoMAD, Royal Society of Chemistry have funded science boxes which are being distributed to local school children - however - the experiments are available online for anyone to take part!

Below you’ll find the experiment introductions, equipment list, method, questions to explore and - very important - health and safety information.

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Introduction

Introduction

Balloons are made of a thin sheet of a polymer called latex, a polymer, and is made up of are made of long, tangled chain-like molecules (think of a bowl of spaghetti). This tangled, network of molecules can be stretched, but when you let go, it returns to its original shape. Such a material is called an elastomer.

When a sharp skewer is slowly pushed, with twisting, into the balloon, the polymer chains are pushed aside so the balloon does not break. When a balloon is blown up, the polymer strands are more tightly stretched around the sides than they are at the ends. It's easier to push the skewer in at the ends, where the strands have more ‘give’ and the skewer can pass through the loose polymer strands Around the side of the balloon, where the strands are stretched more tightly, they are more likely to break. Once a tear begins, it continues to grow, the air rushes out of the balloon, and it pops.

When you give the balloon a sharp poke with the skewer, the strands are broken, and the balloon pops.

Equipment List

· Balloons

· Kebab skewers

What to do

IT IS IMPORTANT THAT YOU HAVE READ THE HEALTH AND SAFETY SECTION BEFORE CARRYING OUT THE ACTIVITY – THE ROYAL SOCIETY OF CHEMISTRY, FRIENDS OF COTTERIDGE PARK AND THE DEVELOPER DO NOT ACCEPT ANY LIABILITY

1) Blow the balloon up so it is still a bit soft

2) Gently push the skewer through the top, darker part of the balloon to the base.

3) Spin the skewer as you press through the balloon skins

Things to investigate

Try skewering the balloon through the sides of the balloon rather than through the ends
Which direction of skewering is best to make a balloon kebab?
Try pushing the skewer thorough a loose and stretched plastic bag – what are the similarities to the balloon?

Health and Safety
(remember to always use common sense)

Risk(s) & Precaution(s)

Puncture wounds to your fingers (from the skewer)
Take not to push the skewer into your fingers and do it under adult supervision

Where can I learn more?

Polymers (RSC website): https://edu.rsc.org/resources/polymers/846.article
Balloon skewers video: https://www.youtube.com/watch?v=vx8gHfZukdU&t=14s

Feedback

We really hope you enjoy the experiments and would love your feedback on the activities and on the science activities and talks at Virtual CoCoMAD (4th July).

To send feedback please use the QR code or the link below to get to the feedback form which will probably take about five minutes to complete. If you do you will be invited to leave your email address and you will be entered into a draw to win a pack of RSC Periodic Table Top Trumps.