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Lab 7: Egglab

Research Question: How does solute concentration affect the movement of water across a living membrane?

Hypothesis: The cell membrane allows molecules to pass into and out of the cell.

Background:The cell membrane serves as a barrier for cells, but how does water move through that barrier? Osmosis is the diffusion (movement) of water across a membrane. Osmosis goes from an area of high water concentration to low water concentration. Osmosis also happens in response to changing concentration of water soluble solutes.

Materials: Raw egg Disposable container Vinegar Syrup String Ruler

Procedure Day 1: 3. Let sit for a minimum of 48 hours in the vinegar.
 * 1) Measure the circumference each egg with string and ruler as indicated in class in your dissection tray.
 * 2) Gently move your egg back into its container and cover with vinegar. Tightly close up the container.

Procedure Day 2: 1.Gently decant (pour) your vinegar in the provided buckets. Measure the circumference each egg with string and ruler as indicated in class in your dissection tray. a.) What has happened to the appearance of the egg?

b.) Is there any difference between day 1 and day 2 circumference? Yes No

2.Gently move your egg back into its container and cover with. Tightly close up the container. 3.Let sit for a minimum of 24 hours in the syrup.

Procedure Day 3: 1.Measure the circumference each egg with string and ruler as indicated in class in your dissection tray. cm a.) What has happened to the appearance of the egg? b.) Is there any difference between day 2 and day 3or 4 circumference? Yes No 2.Clean up. 3. Did the Hypothesis test true or false? Explain.

Saint Xavier High School