With Easter right around the corner, I thought it might be fun to conduct some experiments using eggs.
Egg Experiment #1: Sink or Float?
For this eggs-periment, M tested to see if an egg would sink or float in regular tapwater and in saltwater.
- 2 glasses of tapwater
- a bowl of table salt
- a tablespoon
- 2 eggs
- paper to record observations
- crayons, markers, or pencil crayons to record observations
I put 2 eggs and 2 glasses of regular tapwater on the table in front of M, along with a bowl full of table salt. I told M to add 4 tablespoons of salt to one of the glasses and to stir it well. When he was finished, I asked him to make a hypothesis (a guess) as to whether the eggs would sink or float in the tapwater and in the saltwater. He predicted that in both cases the eggs would sink because ‘the eggs are too heavy’, so I recorded his hypothesis onto the piece of paper. Then M tested his hypothesis by placing one of the eggs into the glass of regular tapwater; the egg sunk.
Next, he placed the second egg into the salt water; this time the egg floated! Eureka!
I explained to M that the egg is more dense than the tapwater, so it sinks. In other words, the egg weighs more than an egg-sized amount of tapwater. When we add salt to the water, the salt makes the water more dense (meaning it is now heavier than the egg) which causes the egg to float on top . Of course I don’t expect M to grasp the concepts of density, displacement, and buoyancy at the age of three, but this experiment is an interesting way to explain why objects float better in saltwater (or the ocean) than in regular water.
I asked M to draw a picture of what he observed/ learned. When he was finished drawing, he explained his picture to me and I recorded his words below his picture.
Egg Experiments #2 and #3
In these eggs-periments, M tested the affects sugary cola and acidic vinegar have on eggs.
- 2 eggs
- a pushpin and a sharp skewer to blow out one of the eggs
- a glass filled halfway with cola
- a glass filled halfway with vinegar
- a spoon
First, I poked a hole into each end of one of the eggs, and slid a skewer through both holes so it would be easier for M to blow out the insides of the egg into a bowl.
Next, M placed the hollow egg into a glass of cola so we could see how it affects the eggshell. He also placed the other egg into a glass of vinegar.
The next day, I took both of the eggs out of the cups and set them onto a paper towel so M could observe any changes. He noticed that the hollow egg that had been inside the cola overnight was now stained brown, and its shell had become soft to the touch. I explained to M that the egg’s shell is like our teeth in that if we eat or drink too many sugary things, the sugar will eat away at the enamel on our teeth, causing them to weaken.
M also noticed that the shell of the egg that had been placed in vinegar had almost completely disappeared! The egg felt really rubbery and M discovered that it actually bounced! I had planned to put the egg back into its vinegar bath for at least another day, but M ended up poking it a bit too hard and it burst apart!
If you leave the egg in vinegar for 2-3 days, you will notice that the shell completely dissolves, leaving a rubbery centre. Rinse the egg and let it dry for another day or two on the counter. Once the egg is dry it will bounce like a rubber ball! M and I are going to do this experiment again so we can test and measure how high we can drop the egg before it bursts!
These eggs-periments were a lot of fun and, as an added bonus, M learned some new scientific terms to add to his growing vocabulary!
Thanks for visiting!