Potato Weights
PURPOSE: To see if the seawater killed the sailor faster than not drinking any water at all.
MATERIALS:
• Potato
• Water
• Knife
• Measuring cup
• Salt
• 8 plastic cups
• Stirring rod
• Saran wrap
• Rubber Bands
• Scale
• Beaker
PROCEDURE:
Measure out 100 ml of water in 4 different beakers. Mark one as “control” and set aside. Add 3.5 grams of slat to one of the remaining beakers. Mark this beaker 7%. Add 14 grams to the last beaker. Mark this beaker 14%. Cut 4 one cm thick slices of potato, measure their mass and record it. Place each slice in its own beaker. Let it sit over night. Take out the slices and record the new masses. Organize measurements in a table. Test this twice.
CONCLUSION: The seawater killed the sailor because it dehydrated him faster than fresh water. The salt in the seawater is what caused that. Osmosis is responsible for the change in the potato slices. This is because the water moves from the outside of the potato to the inside of the potato. Trial 1 is a hypotonic solution and trial 2, 7%, and 14% are hypertonic solutions. One error is that the surface area of the potatoes is not all the same. We can improve this by having a constant surface area.