At-Home STEM Activities: Space Goo with Optional Egg-Drop
Can you make Space Goo strong enough to protect an egg? Find out with this simple at-home activity! Hands-on fun for all ages, with adult supervision (mess potential!)
Materials:
3/4 cup cornstarch
1/3 cup water
2-3 drops food coloring
mixing bowl
spoon or popsicle stick
For optional egg drop:
2 zip-style sandwich bags
2 uncooked eggs (check with an adult before using eggs for this experiment!)
funnel (optional—you can make a simple funnel by poking a hole in the bottom of a disposable cup)
Procedure:
Pour cornstarch, water, and food coloring into a bowl and mix well with a spoon or popsicle stick…You’ve just made SPACE GOO!
Use your stirring implement (and your bare hands, if it’s okay with your adult!) to play around with the Goo…How does it act? What does it feel like?
Notes for supervisors: Space Goo is nontoxic, but is not meant for consumption. Don’t eat it! Dispose of Goo by throwing into a garbage receptacle or compost: it can clog drains if poured down the sink.
What’s Going On?
When you quickly apply a lot of pressure to the Space Goo—like tapping or squeezing—it firms up like a solid. When no pressure is applied, it flows like a liquid. This is one of many materials called non-Newtonian fluids.
Most fluids move faster when they are pushed harder, but Space Goo (and other non-Newtonian fluids) moves slower when more force or pressure is applied. When you slowly stir the Goo, it behaves like a liquid. The same force applied quickly makes it act more like a solid.
Optional Egg-Drop
Place one uncooked egg into a sealed sandwich bag, by itself
Pour your Space Goo into the second sandwich bag, and seal the second egg inside with the Goo
(Handy hint: we avoided a mess by putting the baggie inside an empty glass, folding the edges of the bag upside-down over the rim of the glass, and using a funnel to direct the poured Goo into the bag—see photo)
Make a guess about what will happen when you drop these two bags: will your Space Goo protect the egg?
Perform your experiment:
Take the two bags to an adult-approved location. One-at-a-time, drop each bag from a distance of about 18 inches….What happens? Did the results match your prediction?
What’s Going On?
Your Goo should have protected the egg.
When it hits the ground, a quick direct force is applied to the Goo. The cornstarch clumps together and hardens like a solid, absorbing the impact and protecting the egg. Then, the Goo quickly goes back to acting like a liquid.
Researchers are using shear-thickening fluids (STFs) that behave a lot like Space Goo to make new gels and fabrics. These fabrics are flexible and comfortable when no force is applied, but when struck quickly they harden and provide solid protection.
