Today’s STEAM Activity was learning a simple trick to tell if an egg is hard boiled or not!

I bought 1 1/2 dozen eggs for my kids to color for Easter this year. To get started we needed to hard boil them. We could only fit half in our pot at a time, so half the eggs were hard boiled and half were not. I thought I would teach my kids how to tell the difference!


  • 1 hard boiled egg
  • 1 uncooked (raw) egg


  1. Hard boil eggs using your favorite method (I’ll show you how we did it below) and let the eggs cool
  2. Place one uncooked egg and hard boiled egg in front of your child
  3. Ask your child to spin the eggs and compare how the two spin
    • The hard boiled egg will spin in one spot, quickly, and evenly, and should spin for a long time. The uncooked egg will spin wobbly, move around the table, and stop spinning sooner.
  4. Ask your child to guess which one is hard boiled and which is uncooked
  5. Ask your child to smash the egg they think is hard boiled on their head 😉
    • Just kidding! We didn’t do that step but it sure would be a funny addition to this experiment, especially if they got it wrong. 🤣

Engineering Emily’s hard boiled eggs:

  1. Place up to 12 eggs in a large pot
  2. Cover eggs with cold water
  3. Place pot on stove and bring to a rapid boil
  4. Cover pot and remove from heat
  5. Set a timer for 15 minutes
  6. When timer beeps, drain hot water
  7. Add ice and cold water, making an ice bath to quickly cool the eggs
  8. Once eggs are cooled, move them to the refrigerator
Step 1
Step 2
Step 3
Step 4
Step 7


  • Science: Eggs are cool! When they are heated they turn from liquid to solid. This is the opposite of water which turns from solid to liquid to vapor when heated.

    A hard boiled egg spins easily because its solid on the inside, which makes the center of gravity fixed. The uncooked egg is liquid on the inside, so its center of gravity moves around causing it to spin unevenly as the liquid sloshes from one side to the other inside the shell as the egg spins.

We spun eggs until we cracked both the uncooked and raw eggs. Then we ate the cooked eggs for lunch!

If you try step 5, please let me know how it goes! 😂


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