Eggs are a great example of a cell. Underneath the hard shell is a thin membrane that is just like the cell membranes in your cells. There are microscopic pores in the membrane that allow substances to move in and out of the cell. Way Cool!
Recall that the function of the cell membrane is to control the internal balance of the cell. It helps to maintain homeostasis. In this lab you will use vinegar, an acid, to dissolve the shell off of the egg to expose the membrane. When you place the egg in water you will be able to observe osmosis in action over the next few days. Remember to handle the egg with a lot of care—and don’t forget to wash your hands each time you touch the egg.
Keep Moving! This lab activity takes three days to complete. Once you have this lab set up, go to the next assignment.
Here is the plan.
Below is a copy of the lab report for this lesson. Save this lab report into a file on your computer. You will need to fill in the areas in red. Get ready for some real science! (You will submit this lab report for your 3.05 assessment.)
Cellular Transportation: Movement of Water
•string or thread or yarn
•jar with a lid (Like a mayonnaise jar. Or something big enough to put the egg in.)
•Optional: Karo or pancake syrup
Question: How are cells affected by the movement of water?
Hypothesis: (5 points)
What do you think will happen to the egg after the three days? I think the egg will get bigger
a)Make two observations of the raw egg.
b)Use the string and ruler to measure the circumference of the egg in cm. (Measure the egg around the smaller area.)
c)Gently place the egg in the jar and cover it with vinegar. Put the lid on the jar.
d)After approximately 24 hours from starting the experiment, make two observations of the raw egg.
e)Carefully remove the egg from the jar...