Shock absorbent material to protect an egg

[vikc]

I am doing the Bottle Rocket event for Science Olympiad and I have to have an egg strapped to an air pressured rocket which should not crack on the way down. What is the best and lightest material I can use to absorb the impact? I was thinking of a sponge or cotton. The rocket will be floating down in a slow speed but I still think that it's enough to crack an egg without the proper protection.

 

[rootone]

That 'bubble-wrap' stuff often used for packaging of delicate items being transported?
(Polythene with lots of small air bubbles in it.)
https://en.wikipedia.org/wiki/Bubble_wrap

 

[vikc]

Thanks for the idea!