Today on Sci Guys, osmosis and naked eggs. Welcome to Sci Guys, I'm Adam. And I'm Ryan. Today we're going to be exploring osmosis through making naked eggs. Eggtastic!
Egg salad! Eggcellent! Close enough.
Osmosis is the tendency of water to move across a membrane from a dilute solution into a liquid. a concentrated solution. The ingredients you need for this experiment are an egg, some vinegar, corn syrup, and food coloring.
And the equipment includes a glass and an old spoon or gravy ladle. The reaction we're creating today isn't dangerous, but it's always a good idea to wear a lab coat or apron and goggles just in case it spills and splashes. The first step in our experiment is to take your egg and gently place it on the bottom of your glass. If you break your egg, you're going to have to start over again. Place it on the bottom, and then pour vinegar over top of your egg.
The vinegar is going to remove the shell off the egg and expose the membrane. The shelled egg will need to sit in the vinegar bath for 24 hours. As our egg bathes in the vinegar, the shell is slowly dissolved.
The bubbles clinging to our egg will cause the egg to float, flip, and turn. After 24 hours, you will need to drain the vinegar and replace it with fresh vinegar to continue the process of dissolving the egg's shell. Let the egg sit in the vinegar for another 24 hours. After that, the shell will be fully dissolved and the membrane will be fully exposed.
Once the step is complete, pour out your vinegar into a sink, gently catch your egg, and give it a rinse. Once you have your egg removed from the vinegar, you'll notice it's grown in size compared to this raw egg. This is because water has flown from the vinegar into the egg through osmosis. We're not done yet.
The next step of our experiment is to place your naked egg into a glass, gently. Then, pour your corn syrup over top of it. Bend your old spoon and use it to gently submerge your egg into the syrup.
The naked egg needs to sit in the corn syrup for between 24 and 48 hours. The spoon is used to forcibly submerge the naked egg under the surface of the syrup because the egg will naturally want to float. If the egg floats, the surface of the exposed membrane may harden and it'll also cause this stage of our experiment to go much slower.
Once this stage is complete, pour out your corn syrup using your hand to gently catch the egg and give it a rinse in the sink. As you can see, after a couple of days in our corn syrup, our egg is shriveled and small compared to the previous step where it absorbed a lot of the water from the vinegar. But we're not done yet!
The next step is to fill a glass of water, add a few drops of food coloring, and give it a good stir. Now with your colored water, gently place your shriveled egg into the glass of water and leave it for a few more days. The shriveled egg will need to bathe in our colored water for about 24 hours. The egg will begin to grow and expand as the water passes through the membrane and into our egg.
After 24 hours, pour out your water into the sink and gently catch your egg. Let's look at this experiment a little closer. First we need to look at why the shell of the egg is dissolved by the vinegar.
Vinegar is made up of aqueous, or in other words, a water solution of acetic acid. And the egg shell is mostly made up of calcium carbonate. When we place our egg into the vinegar, the molecules in our glass cause a chemical reaction that produces carbon dioxide gas, water, and calcium acetate.
Once the shell of our egg is removed and we have fully exposed the membrane under it, something really interesting happens. The water molecules in our vinegar begin to travel through the membrane of our egg, and it begins to fill with water. The special thing about an egg's membrane is that it's semi-permeable. What this means is that it'll only let specific molecules pass through it. In this case, the molecules it lets through are water molecules.
When we place our swollen egg into the corn syrup, the opposite effect happens. The water travels through the membrane and into the corn syrup. This movement of water occurs because there is an imbalance in molecules.
The corn syrup has very few water molecules, but lots of sugar molecules. The egg has lots of water molecules and only a few sugars, proteins, and electrolytes. All the molecules want to be in equal proportions on either side of the membrane.
But remember, only water is capable of moving through the membrane. So instead, the water moves from where there's a low amount of other molecules to where there's lots. This means that the water leaves the egg and goes into the syrup.
As the water molecules leave our egg, it shrivels and shrinks. When we place our shriveled egg into the colored water, there's lots of water molecules, but nothing else outside our egg. Inside the egg, there is almost no water molecules and very few proteins, electrolytes, and sugar molecules. So once again, the water moves through the membrane to the inside of the egg, making the proportions of water to other molecules equal, which in this case causes the egg to swell.
The process of water traveling back and forth through our membrane to create our different stages of eggs is known as osmosis. Well, that's it for osmosis. Thanks for watching. Make sure you subscribe on YouTube, like us on Facebook, and follow us on Twitter.
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