Monday, September 14, 2009

Cell membrane experiment

To show how water and other materials pass through a cell membrane using osmosis Dancer used a chicken egg to represent the cell.
It is day one of her experiment and this is just an ordinary chicken egg right from the chicken. The egg circumference measures 5 6/16 inches. Dancer put the egg in a glass of vinegar, covered it with saran and slid it on a shelf in the fridge.
Day 2. She take the egg out and the vinegar has spent the last 24 hours bubbling away at the shell of the egg. The shell is getting soft and has a layer of goo on it. The layer of goo is the dark layer that made the egg brown. The eggs circumference measures 5 5/16 inches so it is getting a bit smaller. Back in the glass it goes with new vinegar and it waits in the the fridge for another 24 hours.

Day 3. The egg's circumference measures 5 12/16 inches so it is getting a bit larger. The shell is now translucent with just one icky end. It gets new vinegar and one more night in the fridge.

Day 4. Much better, the egg is completely translucent and has lost all of it's ick factor. The yolk is also visible in the center of the egg. It's circumference is 6 1/16 inches so it has really grown in size. The vinegar is able to enter the egg once the shell is completely gone. For the next 24 hours it gets covered with corn syrup and goes back into the fridge.

Day 5. It has turned into a sad, saggy, little egg. It's circumference measures a mire 4 4/16 inches because the syrups molecules are too big to pass into the membrane and the egg is trying to make itself match it's environment. For the next 24 hours it will bathe in a glass of plain water.

Wow, what a difference a day makes. The egg is huge, boasting a circumference of 6 4/16 inches! It feels like a balloon and is really quite fun to play with. The membrane is amazingly strong considering we think of eggs as being quite fragile.
Although this was Dancer's experiment, we all really looked forward to seeing what the egg was going to do every day and even Spark gleaned some scientific information from it. Perhaps I should add though that it doesn't take much to entertain us!

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