Osmosis and the Egg In this investigation you will use a fresh hen’s egg to determine what happens in osmosis. You will be measuring the amount of water that passes through the membrane lining the shell of the egg. MATERIALS: fresh egg in shell, wax pencil, graduated cylinder, white vinegar, clear Corn syrup, distilled water, 400 or 250 mL beaker, parafilm or plastic wrap Day 1 Procedure: 1. Measure out 200mL of vinegar using a graduated cylinder and place it in a beaker. 2. Gently place the egg in the jar being careful not to break the shell 3. Cover the beaker with a piece a parafilm or plastic wrap 4. Allow the egg and beaker to rest for 48 hours Day 2 Procedure: 1. Observe what has happened to your egg and record it in figure 1 (data chart) 2. In a CLEAN 400mL beaker, measure out 200mL of corn syrup and place it in the beaker 3. Carefully remove your egg from the vinegar. IT IS VERY FRAGILE SO BE CAREFUL! Very Gently rinse the egg off under SLOWLY running water. 4. Place the egg in the corn syrup 5. Cover the beaker with a piece of parafilm or plastic wrap. 6. Allow the beaker and egg to rest for 48 hours. 7. Using the graduated cylinder, measure the remaining vinegar and then discard it in the sink. Record the volume of remaining vinegar in the chart. 8. Clean the empty beaker with SOAP, WATER and a BEAKER BRUSH. Day 3 Procedure: 1. Measure 200mL of water using the graduated cylinder and add it to a CLEAN 400mL beaker. 2. Remove the egg from the syrup jar carefully and record observations of the eggs appearance in the data chart. 3. Place the egg in the water and cover the beaker with a piece of parafilm or plastic wrap 4. Measure the volume of liquid that remains in the syrup jar using a graduated cylinder and record the volume in the data chart. 5. Clean the empty beaker with SOAP, WATER and a BEAKER BRUSH 6. Prediction: Predict what you think will happen over the next 24 hours. Be sure to consider the size of the egg and the volume of the water. Have the teacher check and initial your prediction before you leave the lab. Day 4 Procedure: 1. Remove the egg from the water and carefully and record observations of the eggs appearance in the data chart. DISCARD THE EGG 2. Measure the volume of liquid that remains using a graduated cylinder and record the volume in the data chart. 3. Clean the empty beaker with SOAP, WATER and a BEAKER BRUSH. Data/Observation Chart Jar Volume Before Egg was Volume After Egg Egg Observations Added was Added Vinegar Syrup Water Questions: 1. When the egg was placed in water, in which direction did the water molecules move? Is water hypotonic, hypertonic, or isotonic to the egg? 2. On what evidence/data from the lab did you base your answer for #1? 3. When the egg was placed in the cornsyrup, in which direction did the water molecules move? Is cornsyrup hypotonic, hypertonic, or isotonic to the egg? 4. On what evidence/data do you base your answer for #3? 5. If you were to place your egg in saltwater overnight, which direction would water move? Is saltwater hypotonic, hypertonic, or isotonic to the egg? 6. What evidence would you have to support this hypothesis/prediction? 7. List at least three possible sources of error (human error or otherwise) in this lab. 8. This lab demonstrates the process of osmosis. What is osmosis? Does osmosis require the cell to use energy? 9. Research Extension: Do some research (internet, other teachers, etc.), find out one way in which osmosis or diffusion affects/impacts humans (medically, environmentally, etc.). Be specific and explain HOW this occurs.
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