In this lab you will investigate how molecules transport in a cell through diffusion and osmosis. You will observe both diffusion and osmosis using an egg and three different substances. You will write a hypothesis, perform an experiment, record observations, collect data, and answer questions after the lab. Below you will find the materials needed for the lab, the procedure for conducting the lab, and a sample layout for your lab notebook page.

Background Information:

The cell membrane surrounds every cell and is the organelle that regulates what moves into and out of a cell. They are selectively permeable which means they only allow certain things to move across the membrane.

Diffusion is the movement of molecules from a high concentration to a low concentration. It is a type of passive transport meaning that it does not require energy from the cell.

Osmosis is the process where water molecules diffuse across the cell membrane from an area of high concentration to an area of low concentration.

For the Lab:

This lab should be done over four consecutive days. You will need to obtain these materials. You should create a lab notebook page to record your hypothesis, observations, and write your conclusions. You can create the notebook page on paper or on a computer.

Materials:

1 raw egg
Container that will hold 2 cups or more (It should be large enough to fully submerge the egg in a liquid)
Tape measure
Vinegar
Corn syrup
Distilled water
Plastic Wrap

Note: Nothing in this lab should harm you, but be careful and ask for help if you need it. Wash your hands every time after you handle the egg and clean your lab area after each day. If you need assistance get adult supervision.

Lab Procedure:

Start by writing a hypothesis to answer the following experiment question: Make sure the hypothesis is in the "if, then" format.

What happens to a raw egg when it is covered first in vinegar, then corn syrup, and then distilled water?

Perform the experiment over 4 consecutive days at about the same time each day. Below you will find instructions for each day:

Day 1:

1. Measure the egg's circumference in centimeters using the tape measure. Record the measurement on the observation table.

2. Record any "before" observations about the egg's appearance (color, shape, texture, size).

3. Carefully place the egg in the container and add vinegar until the egg is fully covered.

4. Cover the container with plastic wrap and leave overnight.

Day 2:

1. Very carefully take the egg out of the vinegar and dry it off.

2. Measure the egg's circumference using the tape measure. Record the measurement on your observation table.

3. Record any "after" observations on your observation table.

4. Clean out the container with soap and water and place the egg back in the container.

5. Add corn syrup until the egg is fully covered. Record any "before" observations on your observation table.

6. Cover with plastic wrap and leave overnight.

Day 3:

1. Repeat steps 1-4 from Day 2 .

2. Add distilled water to the container until the egg is fully covered. Record any "before" observations on your observation table.

3. Cover with plastic wrap and leave overnight.

Day 4:

1. Repeat steps 1-3 from Day 2 .

2. Clean the container and throw away the egg.

When recording the circumference of the egg do so in centimeters. Your observations should describe the appearance of the egg and any other important facts you notice. Look at the color, size, shape, texture and anything that changes about the egg throughout the experiment.

Below is a sample of how to set up your lab page to record your experimental data. You should leave as much space as needed for each part.

Sample Lab Notebook Setup:

1.Describe what happened to the egg after soaking it in vinegar for 24 hours.

2.Describe what happened to the egg after soaking it in corn syrup for 24 hours.

3.Describe what happened to the egg after soaking it in the distilled water for 24 hours.

4.How did you see diffusion and osmosis in this lab?

Fill in the chart as you go through the experiment. When done with the experiment answer the post lab questions. Submit your lab page with your observations and answers to the post-lab questions. You can submit either a picture of your work or upload a document.

Things to remember:

Qualitative observations describe appearance (color, texture, shape, size, smell, etc.)
The variables in this lab are vinegar, corn syrup, and distilled water.
The controlled variables are the egg, beaker, and the time the egg is exposed to each substance.
The independent variable is the substance the egg is submerged in (vinegar, corn syrup, and distilled water).
The dependent variable is what happens to the egg after being exposed to the three different substances.

Biology Special Lesson: Diffusion Lab

This rubric is an outline of how the lab information you submit will be graded.

Grading Rubric