The Incredible Swimming Egg
Eggs don’t float, but some can swim!
How it looks:
You drop an egg into a glass of water and ask the audience, “Can anyone make this egg float to the top of the glass? With a pinch of magic potion and some magic words, I will show you how to teach an egg to swim!”
You take out a plastic bag and take a pinch of “magic potion” from it. You sprinkle a few grains of magic potion into the glass while stirring it with your finger. “Now, for the magic incantation. From the depth of this glass filled to the brim, wake up little egg, it is time to swim!” The egg rises to the top due to the stirring, but sinks back to the bottom of the glass.
You add a spoonful more of the magic potion, stir the glass and say the magic words again, louder this time, “From the depth of this glass filled to the brim, wake up little egg, it is time to swim!!” Again, the egg rises and then falls back down.
You pour the rest of the bag of potion into the water, stir and scream out, “Swim! Swim!! Swim!!!” This time the egg rises to the top and stays there even after the water stops stirring. You smile and say, “Sometimes it just takes a bit of egg-couragement.”
What you need:
- A clear glass of room temperature water (just large enough for an egg to rest on the bottom of the glass)
- 1 egg
- Salt (6-10 tablespoons or 90-150 mL)
- Small bag or container (non-transparent – something that you can’t see through)
- Adult helper
How it works:
The “magic potion” is just salt hidden in the plastic bag. When you add salt to the water, you make it heavier, or more dense, than the egg. This is why the egg floats. With a bit of experimenting, you can add just enough salt to make the egg float halfway up the glass.
Did you know…
If the egg floats before you add salt to the water, it may not be a fresh egg.
When an egg is first laid, it is warm. As it cools, the contents contract (shrink) and form an air pocket at the large end of the egg. As the egg ages, this air pocket grows in size (air replaces gases that escape through the egg’s pores), making a “lighter” egg that floats!
Sources: Adapted from www.canadaegg.ca and www.aeb.org