Dropping a stone on an egg (without breaking it), exploring gravity.

This unit starts with some storytelling - eggs are facing challenging times within these learning scenarios. First they were dropped from a height, next their strength will be tested from above.  For this challenge, students will need to save the eggs with suitably stable structures to protect them from falling bricks!

Introducing a new method: thinking backwards. This activity is designed to free up the imagination and encourage students to explore their creativity by thinking backwards. This means considering all the potential pitfalls to work out exactly what you need to do to prevent things from going wrong. The more specific scenarios they think of, the more likely they are to cover every eventuality. For example: the egg rolling out of the protection and cracking, the skewers being weak and falling over, the skewers falling apart if they are not properly attached. Students should think of as many ‘accidents’ as possible.

Presenting the challenge: how to drop a brick on an egg without breaking it. The students will make an ‘egg protector’ from skewers. The protection must not be attached to the ground. The egg and its protector will be put on a tarpaulin, and a brick will be dropped on it from a height of 50 centimetres. From the eggs that remain intact, the winner will be the protector made with the least resources.

• Working in groups, begin by considering the construction. Sketch out the design.
• Start to explore the detail of the construction by building a prototype in sections, for example, working out the connection between the skewers.
• Use an egg shaker for testing rather than a real egg (name it and give it a persona). Once each element of the prototype is developed, work on the whole structure. Try to take different scenarios into account and use different approaches to problem-solving.

Stop work for a plenary to check progress – sharing, testing and feedback:

• Each group should show how their ‘egg protector’ is made, how it works, what materials they used, what choices they made, what problems they had to solve to teach each other what they have learnt. When giving each other feedback, students should critically discuss the design: see where the strengths or weaknesses of the structure manifest.
• Students will place a real egg into their ‘egg protector’ and put it in the middle of the tarpaulin. Take a photograph of the protector intact.
• Drop the brick from a height of 50 centimetres, one group at a time. Discuss the outcome between each drop. Cherish the eggs that survived!

Back in the classroom, make an inventory of each group and their egg. Share the results on a scoreboard, recording egg name, the number of materials used in the structure, and result using this symbol system: a fried egg indicates that the egg was completely broken, a whole egg with a crack in it indicates that the egg was broken but still kept its shape, an unbroken egg indicates the challenge was a success.

The winner is the group with an unbroken egg and the fewest materials used

Within the results, evaluate which aspects of each design were good ideas and which ones were less successful. Discuss the new method of thinking backwards. Did it work for them? Were they able to predict the accidents? As students don’t always understand all the skills they have used to accomplish the assignment, name the skills they used explicitly and give positive feedback.