Believe it or not, there are days when my kids aren’t excited about doing science with their dear ol’ Mom. Especially a few weeks ago when we didn’t have school due to the flooding of Tropical Storm Imelda and we were all bored. On that hot and muggy morning this was our conversation:
Me: “Want to make slime?”
Kids: “Nah…”
Me: “How about a little oobleck?”
Kids: “No thanks…”
I looked at the clock, it wasn’t even 9 o’clock yet… this was going to be a long day. I kept slowly flipping through some old science books and took another swig of coffee. Then it came to me.
Me: “Want to suck an egg in a bottle?”
Kids: “What did you say?”
Now I had their attention. Here’s what we did.
What you need: an adult, a peeled hard-boiled egg, cotton ball, match, and plastic juice bottle (the classic experiment calls for a glass container but we used our plastic juice bottle since that’s what we had on hand)
How you do it:
- Rinse and dry a juice bottle
- Light a cotton ball with the match and place in the juice container (there won’t be as much smoke with a cotton ball)
- Place the peeled hard-boiled egg over the container
- Brace yourself to be amazed
What’s the science:
Actually, the egg isn’t sucked into the bottle (nor is it melting). The lit cotton ball heats the air inside the bottle causing the air to expand. Some of this hot air escapes by lifting the egg off the top. Once the fire is extinguished, the air inside the bottle cools and contracts causing a partial vacuum. The pressure inside the bottle is less than the air pressure outside of the bottle causing the egg to be pushed in from the outside air pressure! (Side note: We found that with a plastic container you could only do this experiment once since the bottle deforms.)
So on that hot muggy day following a tropical storm, science became fun once again…. and I confirmed that there is a reason why this one is called a classic.
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