Name______

Period______

The Incredible Egg-Speriment

Due ______

This trimester, we will be studying the cell which is the basic unit for all living things. In this project, you will model how a cell membrane works to let water and other substances enter and exit the cell. You will use a chicken egg as your model of a cell.

After dissolving the shells in vinegar to expose the membranes, you will soak your eggs in various liquids and observe how the size of the eggs change as they take in or lose water through their membranes. You will record both quantitative and qualitative observations of the eggs.

You will learn about osmosis which is the diffusion (movement) of water across a membrane from high concentration to low concentration until both concentrations inside the egg and outside in the liquid are equal (equilibrium). Water molecules are small enough to pass through a cell membrane, but other molecules may be too large to move.When you put a cell (or egg) into a solution, it will take in water, stay the same or lose water; what happens depends on the concentrations of solutes on either side of the membrane.

Materials Needed:

Name______

Period______

  • 3 uncooked eggs
  • 3 small containers with lids
  • String or dental floss
  • Ruler
  • White vinegar
  • Corn or Maple Syrup
  • Water
  • Liquid of your choice (safe for student use – no bleach, beer, bodily fluids, etc.)
  • Large spoon or ladle
  • Plate
  • Soap
  • Paper towels
  • Parent permission

Name______

Period______

Directions:

1.Gather all materials. Start with 3 eggs…At least one will probably break !! Label each container to keep the eggs separate.

2.Set up a data table in your science journal (in class)

3.Make hypotheses (in class)

4.Record your observations and measurements of ALL 3 EGGSbefore the experiment.

5.Soak 3 eggs in separate containers filled with white vinegar for at least 2 days or until the shell dissolves. The egg should feel like a water balloon.

6.Record your observations and measurements of ALL 3 EGGS after being in the vinegar. Be careful; they are fragile.

7.Soak eggs in separate containers filled with maple or corn syrup for 2 days.

8.Record your observations and measurements of ALL REMAINING EGGS after being in the syrup.

9.Soak eggs in separate containers filled with waterfor 2 days.

10.Record your observations and measurements of ALL REMAINING EGGS after being in the water.

11.Soak eggs in separate containers filled with a liquid of your choice for 2 days.

12.Record your observations and measurements of ALL REMAINING EGGS after being in the liquid of choice.

13.Complete the lab write up using the template your teacher gives you as your guide. Keep one egg in a container to bring to school on the due date for your presentation.

Making a Supersaturated Solution

If you decide to make your own liquid, you are going to want to make sure you have enough solute relative to the amount of solvent (usually water). Water can hold more solute when it is warm because the molecules are moving rapidly, so heat up your water, then add the solute and stir well. Keep adding solute until it falls out of solution. Do keep track of how much solute you have added! Allow your solution to cool back down to room temperature before you add your eggs.

Measuring your egg

  • For best results in this project, it is important to measure your egg carefully each day. This is because changes in circumference of the egg may be slight, and measurements that are not precise may mask changes that have occurred.
  • Measure the circumference of your egg at the egg’s equator in millimeters (mm) as shown below.
  • Follow these steps:
  • Carefully take the egg out of the liquid and pour the liquid down the drain.
  • Rinse the egg over the sink and blot it with a paper towel.
  • Use a piece of string to measure the circumference of the egg following these steps:
  • Wrap the string snugly around the egg at the equator.
  • Grasp the string between your thumb and finger at the point where the end of the string meets the rest of the string after circling the egg.
  • Keeping your thumb and finger in place, lay the string straight on a flat surface.
  • Using a ruler, measure the distance from the end of the string to the point where you are holding it in MILLIMETERS!!!
  • Record measurements and observations in your data table.
  • Return your egg to the container and cover it with the same or another liquid, according to the project rules above.
  • WASH YOUR HANDS!

If you are a twin, please see me for instructions on how to coordinate data collection with your sibling. Each person must turn in his or her own lab report written by him or herself only.