materials required and procedure for osmosis experiment with egg
Answers
3 eggs
3 glasses (large enough to fit the egg plus liquid)
3 butter knives
White vinegar (about 3 cups)
Distilled water (about 2 cups)
Light corn syrup (about 1 ¼ cups)
Slotted spoon
Measuring cup (1 cup)
Measuring spoons (1 tablespoon and ½ tablespoon)
Sticky notes and marker
Scale (optional)
Procedure
Note: It’s okay to touch the eggs, but remember to wash your hands afterwards to avoid any nasty surprises!
Place one egg in each glass. Pour in enough vinegar to cover each egg. Bubbles will start to form around the egg, and it’ll float up. To keep it submerged, put a butter knife in the glass to hold it down.
Put the three glasses in the refrigerator and allow to sit for 24 hours.
Gently holding the egg in the glass, pour out the old vinegar. Replace with fresh vinegar, and let sit in the refrigerator for another 24 hours. Repeat this process until the shells are fully dissolved and only the membrane remains. This should take about 2-3 days.
Gently remove the eggs using the slotted spoon and rinse with tap water in the sink. Rinse out the empty glasses as well.
Gently put the shell-less eggs aside for a moment on a plate.
Prepare three different sugar-water solutions as follows, labeling with sticky notes:
Glass 1: Label “hypertonic”. Pour in one cup of corn syrup.
Glass 2: Label “isotonic”. Add 1 ½ tablespoons corn syrup to the one cup measuring cup, and fill the remainder with distilled water. Pour into glass (make sure you get all the corn syrup out!) and stir to dissolve.
Glass 3: Label “hypotonic”. Pour in one cup of distilled water.Gently put one shell-less egg in each of the glasses, and let sit in the refrigerator for another 24 hours.
Materials
3 eggs
3 glasses (large enough to fit the egg plus liquid)
3 butter knives
White vinegar (about 3 cups)
Distilled water (about 2 cups)
Light corn syrup (about 1 ¼ cups)
Slotted spoon
Measuring cup (1 cup)
Measuring spoons (1 tablespoon and ½ tablespoon)
Sticky notes and marker
Scale (optional)
Procedure
Note: It’s okay to touch the eggs, but remember to wash your hands afterwards to avoid any nasty surprises!
Place one egg in each glass. Pour in enough vinegar to cover each egg. Bubbles will start to form around the egg, and it’ll float up. To keep it submerged, put a butter knife in the glass to hold it down.
Put the three glasses in the refrigerator and allow to sit for 24 hours.
Gently holding the egg in the glass, pour out the old vinegar. Replace with fresh vinegar, and let sit in the refrigerator for another 24 hours. Repeat this process until the shells are fully dissolved and only the membrane remains. This should take about 2-3 days.
Gently remove the eggs using the slotted spoon and rinse with tap water in the sink. Rinse out the empty glasses as well.
Gently put the shell-less eggs aside for a moment on a plate.
Prepare three different sugar-water solutions as follows, labeling with sticky notes:
Glass 1: Label “hypertonic”. Pour in one cup of corn syrup.
Glass 2: Label “isotonic”. Add 1 ½ tablespoons corn syrup to the one cup measuring cup, and fill the remainder with distilled water. Pour into glass (make sure you get all the corn syrup out!) and stir to dissolve.
Glass 3: Label “hypotonic”. Pour in one cup of distilled water.Gently put one shell-less egg in each of the glasses, and let sit in the refrigerator for another 24 hours.
osmosis-graph
Remove the glasses from the refrigerator, and gently put the eggs on a plate. If you weighed the eggs before putting them in each solution, weigh them again. What happened to each of the eggs?
egg-experiment-3
How does osmosis work?
Osmosis is the scientific term that describes how water flows to different places depending on certain conditions. In this case, water moves around to different areas based on a concentration gradient, i.e. solutions which have different concentrations of dissolved particles (solutes) in them. Water always flows to the area with the most dissolved solutes, so that in the end both solutions have an equal concentration of solutes. Think about if you added a drop of food dye to a cup of water – even if you didn’t stir it, it would eventually dissolve on its own into the water.
In biological systems, the different solutions are usually separated by a semipermeable membrane, like cell membranes or kidney tubules. These act sort of like a net that keeps solutes trapped, but they still allow water to pass through freely. In this way, cells can keep all of their “guts” contained but still exchange water.
Now, think about the inside of an egg. There’s a lot of water inside of the egg, but a lot of other things (i.e. solutes) too, like protein and fat. When you placed the egg in the three solutions, how do you think the concentration of solutes differed between the inside of the egg and outside of the egg? The egg membrane acts as a semipermeable membrane and keeps all of the dissolved solutes separated but allows the water to pass through.