Thursday, March 19, 2015

EGG-citing EGG-speriments!

In anticipation of Spring Equinox this Friday, we decided to do some egg themed experiments.

The first focused on osmosis, with a bit of chemistry as well.

1 egg (fresh, not hard boiled)
clear container
white vinegar
corn syrup

Osmosis is the movement of materials in a solution across a membrane, typically from areas of high concentration to areas of low concentration. An egg has a membrane we can use to see this, but first we have to get rid of the shell.

Before we began we found the weight of our egg on a simple kitchen scale. Ours was 2.25 ounces. We then placed our egg in a glass and covered it with vinegar. The acetic acid in the vinegar reacts with the calcium carbonate in the egg shell to make calcium acetate and carbon dioxide. The bubbles were visible almost immediately.

We left the egg in the vinegar for 48 hours and got this- 

Since the vinegar had a higher concentration of water than the inside of the egg, some water moved into the egg by osmosis. At this point the egg weighed in at 3 ounces. We put it back in the glass and covered it with water to see if it would take on even more water.

After just 30 minutes in water the egg looked like this. The lighting accounts for some of the color change, but not all. At this point the egg weighed 3.25 ounces. 

We then poured out the water and covered the egg in corn syrup. The corn syrup has a lower concentration of water than the inside of the egg, so we're expecting to water to now move out of the egg into the corn syrup.

At this point the egg had been in the corn syrup for about 4 hours. You can clearly see the less dense layer of water which has come out of the egg floating on top of the more dense corn syrup. We left the egg overnight in the corn syrup.

We woke up to this. The egg weighed 1.25 ounces, losing a total of 2 ounces from when it was placed in the corn syrup. 

We had so much fun with this experiment! The boys especially loved touching the egg without it's shell and showing everyone who would look at it in the various stages. 

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