Homeschool Conference!!!

Look at all those beautiful little feet two people can create!

Look at all those beautiful little feet two people can create!

Thursday, October 3, 2013

Osmosis and Naked Eggs

Science Experiments are a FAVORITE around here!!!

Want to know a little more about OSMOSIS??? 
Or "Awesome-osis" as my kids would call it!

Okay, then join us in making a "NAKED EGG"!

Simple Supply List:
A Jar
Apple Cider Vinegar
An Egg

In a few days, you'll need:
A clean jar
Corn Syrup

Let's get started!!!

How to make a Naked Egg
A “naked egg” is simply an egg that no longer has its shell... 
The shell will be gone – yet the egg stays intact, held together by two fragile membranes just inside the shell of the egg.  
The shell of an egg is made up of calcium carbonate. 
When you place your egg into a jar filled with apple cider vinegar, you start a chemical reaction that dissolves the calcium carbonate shell. This is due to the acetic acid in the vinegar;  it reacts with the calcium carbonate in the egg shell and releases carbon dioxide gas that you will begin to see as bubbles on the shell.

Are you ready to check it out???
Grab your jar and gently place the egg inside and cover with apple cider vinegar...
your egg will most likely start to float...
don't worry if it is not completely covered, it will work out just great!  
Then cover the egg either with the lid to the jar or with a piece of aluminum foil.  
Then stick it in the fridge and prepare to be patient for the next few days.

The only job you will have over the next number of days will be to just gently swish the egg around, check out the bubbles (remember the carbon dioxide gas we talked about...it's happening now) and take careful notice of what is happening to your egg...the shell is beginning to disintegrate and float around and may form a layer of "stuff" on the top of the liquid.


After a few days of soaking in vinegar, you will end up with a pretty cool Naked Egg. 
Be sure to notice that your egg is a bit bigger than when you first started. 

This is because some of the vinegar (and some of the water in the vinegar) has moved through the membranes to the inside of the egg. The membranes are semi-permeable and allow water to move through them. This is called osmosis.  (For a better understanding of how osmosis works...check out the info at the end of the post)

When you remove your egg from the vinegar, you may be a little surprised at the new texture...it feels quite "rubbery"...
we did the Bounce Test to check out just how rubbery and tough our naked egg had become...but before doing the Bounce Test, we were curious to see if we could shrink our egg and cause it to shrivel up.  

So can YOU Shrink your Egg???
You bet...
all you need to find is a liquid that contains a very small amount of water...
corn syrup is a perfect match for such a job!

Time to grab your next round of supplies ~ you will need a clean jar or glass and enough corn syrup to cover your naked egg.  
 Now, the waiting time starts again...
give it a day or two (we did two days) and see what happens!
When we pulled ours out, it was still very much intact, seemed MUCH more fragile and looked a little baggy, shrunken and raisin-like.  
How did this happen???
Well, corn syrup has very little water content, so the water inside the egg begins to move across the semi-permeable egg membrane to equalize the water concentration. Again, that’s osmosis at work. You could leave your egg inside the corn syrup until it shriveled up to look just like a big raisin with the yolk inside.

And IF you are as crazy as we are 
and you just cannot seem to get enough of this Naked Egg Experiment...
just reverse this process again by tossing 
(No Don't Toss, gently 
place your egg inside a clean glass again) 
and cover with water...
The water will do its magic again and move across the membrane filling the egg with water and in a couple days your Naked Egg will be nice and rubbery...

leading you to another fun experiment to try out...
The BOUNCE TEST!!!

We didn't video the 1inch drop up to the 6 inch bounce test...but decided after a while that we NEEDED to have proof of just how amazing this naked, rubbery egg was...so here you have it!!!

(side note:  As I've watched the video a couple of times now, it occurred to me that I have one very interested son...he made it up to the front of the crowd and was DETERMINED to save the egg from impending doom...only to be told to stop many times...lesson to me (as Mom and Teacher) ~ some kids just feel things so much more intensely than others, embrace it and love it...they are special and unique and I am lucky enough to be his Momma!)


For further clarification on Osmosis, read below:  Sorry, that I don't know who to give credit to for these words...but to whomever, thank you!

It's diffusion of water through a semi-permeable membrane (a membrane that's semi-porous) from an area of low solute concentration (less stuff in the water) to an area of high solute concentration (more stuff in the water). Or in other words, water will flow from an area of high pressure to an area of low pressure. 

Here's a way to look at it, that'll be helpful for you. 
A hypertonic solution is a solution that has lots of stuff in it. What happens when you have lots of stuff in the water? Well you're going to have LESS water. Right? A hypotonic solution is a solution that has less stuff in it. When there's less stuff in it, there's going to be a lot more water. 

In nature everything needs to be balanced, something called equilibrium. Whenever you place a cell in a solution that is hypertonic (lots of stuff in it), the solution is obviously going to have less water than the cell. So what happens is the cell's water flows outwards into the solution to balance out. Because all the water flows out of the cell, the cell has little water left and so it shrinks in size. Another way to think of it is the water went from an area of high concentration (the cell) to an area of low concentration (the surrounding solution). 

If you place the same cell in a hypotonic solution (a solution that has less stuff and more water), the cell will then have more stuff in it than the surrounding solution. Because the cell has more stuff in it, that means the water in it is less than the surrounding solution. In other words, the amount of water in the solution is higher than the cell. So the water flows INTO the cell, causing it to swell up. Another way to think of it is the water went from an area of high concentration (the surrounding solution) to an area of low concentration (the cell).