Children may learn about osmosis by participating in this fun science experiment. Excellent all year long, but particularly useful for a scientific lecture on Halloween!
Osmosis is a crucial topic to understand for the study of biological systems, yet it may be difficult to conceptualize. This entertaining scientific experiment gives a traditional kid-friendly science experiment a unique twist.
The passive transfer of water molecules from a high water potential region to a low water potential area is known as osmosis. Osmosis and diffusion are quite similar in that they are both passive processes that don’t need energy input. Both osmosis and diffusion involve the very random movement of molecules, yet they both result in a net movement of molecules from high to low concentration. The molecules ‘desire’ to be uniformly distributed until they achieve equilibrium, or equal dispersion.
Read more: Fun and easy science activities for kids
Potatoes are Used to Show Osmosis
Cut raw potato cubes may be used in a well-known experiment to show the osmosis:
- Two beakers should be ready, one holding water and the other a salt solution. The strength of the salt solution doesn’t really important, but if kids are making the beakers themselves, it may be used to emphasize the concept of saturated solutions.
- Using a ruler and a knife, slice a potato into 1 cm cubes. For each beaker, create a cube.
- Place the potato cubes in the beakers at a depth of 1 cm, and then wait for around 30 minutes. Students may prepare a results table and write up their technique during this period.
- Potato cubes should be removed after 30 minutes and measured.
The potato cube that was submerged in water should have grown larger, whereas the potato cube that was submerged in salt solution should have shrunk. The cubes may be weighed before and after the measurement to get a more precise reading, and the mass change could then be determined.
Why Osmosis Happens
A potato’s cells contain mostly, but not fully, water (60 to 80% depending on the type). This is the experiment’s key.
Assume that 70% of our potato is water. There is an imbalance if we put it in pure (100%) water. Outside of the potato cells, there is a larger water potential than within. As a result, water molecules will attempt to migrate inside the potato in order to establish equilibrium. The potato cube swells as a result, increasing its size (or weight) when measured.
When we submerge the potato in a salt solution with a high concentration, the reverse happens. The water potential outside the potato cells is lower than on the inside because a large portion of the water molecules in the salt solution are involved in dissolving the salt. As a result, water will strive to equalize the solution’s concentration by moving from the potato into it. The potato cube contracts and loses bulk as a result of this.
Using Creativity to Make Science Haunting!
Potato cubes are fine and all, but this eerie twist on the experiment is more entertaining:
- Give a potato and a variety of clay sculpting tools to each group of kids.
- Remove the potato’s peel after cutting it in half.
- Give each potato half a face.
- Calculate the mass of the cut potatoes by weighing them.
- Submerge in a saltwater solution (as above).
- Reweigh the potato faces after the 30-minute mark.
The potato face in the water should have become bigger and swollen. The potato face in the salt solution ought to have lost mass and shrunk up to create the eerie shrunken head image.
Distinctiveness and Adaptability
By creating shrunken Halloween heads at home using just salt solution and seeing the result, this activity may be utilized as a fun project for younger kids.
Calculations like % change in mass might be included in the lesson for pupils who are more mathematically adept.