Which Witch is a Real Witch?

A Lesson in Density and the Middle Ages

Our experiment today involves three suspected witches. We are going to scientifically determine how many of these suspected witches are actual, real life witches.
According to the logic of the Middle Ages, a witch would float on top of a body of water while an innocent person would sink like a stone. We are using this same logic in our experiment today.

We obtained three fresh eggs and drew witches on each of them with a permanent marker. Then we filled up three cups of water (about 10 ounces each) and submerged each egg.

The results?

Well, I forgot to mention that we added salt to two of the cups. Minor detail, right?

Cup #1 (yellow) contained no salt and the egg sank like a stone = Innocent person!

Cup # 2 (black) contained 2 Tbsp of salt and the egg still sank = Innocent person!

Cup #3 (blue) contained 4 Tbsp of salt and the egg *DRUM ROLL, PLEASE* floated = WITCH!

Even when we tried to make Egg #3 sink, it kept bouncing back up to the top to float. So why did this happen?

At first Tommy thought it must be something to do with the egg. He hypothesized that the eggs that sunk were heavier than the egg that floated. We tested his hypothesis by trading Egg #2 and Egg #3. He was a little baffled by the fact that the egg in Cup #2 still sank and the egg in Cup #3 still floated. Hm, looks like it wasn't because of the egg afterall.

Then we talked about the difference in the water and voila! The light came on! It was because of the salt!

See, when salt is added to water it makes the water more dense. You can think of it like the water gets heavier. If you add enough salt you can actually make it more dense than an egg, which makes the egg float.

Does this mean that ocean water is more dense than fresh water? Yes, yes it does.

Want another example of density? Head on over to Color Bombs or the Lava Lamp to see how water is more dense than oil.

What do we do with witches? We cook 'em! Enjoy :)

This experiment came from 100 Science Experiments, a book we love and reference all the time!

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Saturday Science Blog Hop

It's time for our weekly Science Linky Party! I loved all the great ideas that were shared last week. Today I am featuring Spooky Sound Science from One Time Through. Grab some random objects from around the house and practice your spooky sounds for Halloween!

Check out our co-hosts:

Preschool Ghostly Bubble Science: Fun Ways to Play With Bubbles from Little Bins for Little Hands

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