Friday, December 12, 2008

Having biological fun

This week we did one of my favorite labs, Egg-cellent Ideas for Osmosis and Diffusion from The Science Spot. Noach is reading about cells and cell membranes.

First we dissolved the eggshell of 2 eggs in vinegar. After finding their mass, we took the naked eggs and put one in blue water and the other in karo syrup. They were refrigerated for 24 hours and then examined and the mass measured again.
Egg 2, was placed in syrup, which was hypertonic relative to the egg white. Water passed through the membrane by osmosis and the egg was somewhat deflated. It was 11.9 g lighter. We also noted that the karo syrup had a layer of water on top of it, because the water was less dense than the syrup.
Egg 1 which had been in blue water was tense when taken out. The membrane was thick and blue. Water moved into the egg because the water was hypotonic relative to the egg white which has proteins dissolved in it. The egg's mass increased only slightly, 4.7 g, but that was enough to make the blue water inside the membrane to squirt when pierced.

Science fun! PRM


Lorna said...

That is a great experiment. I have been amazed about how much one can learn quite complex scientific concepts with the every day things in the kitchen or garage.
I have so little experience with biology, I find your posts great inspiration, thank you!

Fairion said...

What a great experiment. I am new to your blog but am hooked. How old are your children? I have filed this experiment for when Froggy is old enough.

Ruth in NC said...

My children are 18, 16 and 12. And 31.

As my mother said when my brother turned 60, "When did my children get so old?"