Hold the Salt!
Have you ever wondered why eating salty foods makes you thirsty? In science class, you have been learning about cell processes. During one of those processes, called osmosis, water passes into and out of cells. In this activity, you and your family members can watch what osmosis can do to a slice of potato.
- potato slices (peeled, about ¼ inch thick)
- tap water
- 2 small containers (bowls, glasses, or mugs)
- table salt
Ask an adult to help you fill each container with warm tap water. Label one of the containers, “Tap Water.” Add two spoonfuls of salt to the other container, and stir until the salt has dissolved. Label this container, “Salt Water.” Place a potato slice into each container. Make sure the slices are completely covered with water. After 30 minutes, take the potato slices out of the containers. Observe them.
What happened to the potato in the tap water? What happened to the potato in the salt water? How do the results of this activity help you explain why your mouth feels dry after you’ve eaten salty foods?