If you did not see my Saint Patrick’s Day post please head on over and check it out. We did so many fun activities that day that I am sure you and your family would enjoy doing too.
The big experiment we did was Rainbow Naked Eggs from Schooling Active Monkeys. After we set them up ALL Spencer could talk about was his eggs. He checked them all the time and wanted to know if they were ready yet. Poor kid, science takes time. And this experiment takes between 48 -72 hrs to be exact. 2-3 days is FOREVER to a preschooler. It meant though that his mind was working and he was curious for days. I have to say I loved how engaged he was in this whole thing.
The Set Up
Glass Jars – I used pasta sauce jars, you could use mason jars. You just need a glass jar with a lid
1 regular egg in water – That is the control
1 red vinegar jar, 1 orange vinegar jar, 1 yellow vinegar jar, 1 green vinegar jar, 1 blue vinegar jar and 1 purple vinegar jar.
Part 1 – Dissolving the Egg Shell
ROY G BIV is your friend here. This is the correct order of wavelengths in the visible spectrum. Violet has the shortest wavelet and red has the longest wavelength 400-700 nanometers (nm)¹ When white light is shown through a prism or a rain droplet its splits into the colors of the visible spectrum making a rainbow.
I am crazy about ROY G BIV. Since he was a baby with finger paints I have always put the colors in the right order. I just want this to be something that is ingrained in him and he just knows the correct order…. Anyhow.. Moving on. (I even started telling him about visible light the other day when we saw a rainbow through the water tower bottle on the floor – I know I know he is 3, but its never too early to foster a curiosity for the world around us. And now whenever he sees a rainbow on the wall because of the water tower he gets all excited and jumps around.)
The egg shell is made up mostly of Calcium Carbonate. Household vinegar is an Acetic Acid dilution, meaning there is a lot of water in it. So when you put the two together the egg shell is dissolved and carbon dioxide and water are created. The egg swells because there is more water on the outside of the semipermeable membrane than on the inside. If you remember osmosis from school you will know that water will move from the high concentration to the low concentration in an attempt to balance out the concentration on either side. The fluid inside the egg (the egg white) does not have as much water in it as the solution the now naked egg is floating it. So the water molecules and the dye move across the membrane swelling the egg and coloring it, this is called diffusion.
There are a few chemical reactions going on in your jar:
CaCO3 + CH3CO2H → H2CO3
Calcium Carbonate + Acetic Acid → Carbonic Acid
And at the same time this reaction is happening
2 CH3COOH + CaCO3 = H2CO3 + Ca(CH3COO)2.
Acetic Acid + Calcium Carbonate = Carbonic Acid +Calcium Acetate
The full chemical reaction is listed below
2 CH3COOH + CaCO3 = H2O + CO2 + Ca(CH3COO)2
Acetic Acid + Calcium Carbonate = Water + Carbon Dioxide + Calcium Acetate ²
Anatomy of an Egg
I realize you aren’t going to walk your preschooler through the ins and outs of exactly what is going on. But I do hope that you will do this experiment a few times as they grow and you can go a little more in depth into the explanation each time. This would even make a great elementary school science fair project.
Four Days Later… The Results
Daddy was really excited about this experiment so I decided to wait an extra day so that we could all see what the eggs looked like together. Neither of us had ever done this experiment and we were just as excited as Spencer.
We had beautiful Rainbow Naked Eggs that were huge and bounced! The eggs get so swollen and feel squishy. I literally was able to bounce the eggs, I wasn’t that daring so I only bounced it about an inch or so. Spencer had proven just how fragile the eggs were and accidentally popped one. We think he squeezed it just a little bit. It literally got everywhere. There was so much water in the egg I want to say the spray was a good 6 feet. So we lost the blue egg, which was a bummer because I wanted to do a second vinegar bath as part of part 2 of the experiment. We immediately cleaned everything with Clorox wipes because don’t forget these eggs are RAW. I have to admit I was a little grossed out by having raw egg all over my kitchen, but it was in the name of science and I couldn’t blame my little scientist for wanting to squeeze the egg. I had too. Look at how big those eggs are compared to the control egg that soaked in water for 4 days. They are HUGE!
Unfortunately when Mommy mixed the orange apparently I put too much red in the mix and the red and orange eggs were very similarly colored. We cut into the orange egg to see if the yolk changed color. It hadn’t. When I pricked the egg with the knife it practically exploded on the plate, so be aware. Science can be VERY messy, especially when done with young children. Look at how much water was in that egg! The membrane after being exposed to the vinegar felt very much like a balloon.
We also looked at the colored eggs with a flashlight. Spencer loves flashlights so he particularly enjoyed this part. However we really couldn’t see the yolk within the dye. I used very strong food coloring and that might be why or it could have been that we looked during the daytime and I could not fully block the sun. Next time we do this experiment I will soak an egg in vinegar but without any food coloring so we can see what the egg would look like just naked.
Note* We thought the eggs may have been done at two days so we took the green egg out and tried to rinse it. The shell was not completely dissolved so we put it back in a fresh vinegar solution.
Look at how excited this kid is about science! I love it! He could barely keep his hands off the eggs.
This is a two part science experiment. Part two is called an Osmosis and Diffusion Experiment.
All in all this was an incredibly fun activity that had us all talking for days. I hope you decide to do this with your family. If you do please let me know by posting pictures on our Facebook page. If you enjoyed this post please share it!