Cool Science- Lesson 4 – Osmosis - Water passing through the skin of a plant?

A Cool thing about plants, is they can absorb water through their skin. This is called Osmosis, and guess what? you can do it yourself to see it happening.

Source

What we need for the experiment – (Parents ensure to assist the kids)

· 2 glasses with a wide opening

· Water

· Iodine (which can be obtained at a pharmacy)

· Some corn-starch

· A plastic bag that you can seal off

How to do it

1. Fill the glasses with plus minus three quarters of water

2. Place 2 teaspoons of iodine with water in the one glass

3. And in the other glass you have to mix one tablespoon of corn-starch with the water and place half of the content in the seal-able plastic bag

4. Now seal the plastic bag and put it right into the iodine mixture

5. Leave the sealed plastic bag in the iodine for about and 60 minutes and see what happens. In the meantime, place a few drops of iodine into the glass with the corn-starch in it and see what happens

What’s happening?

The corn-starch that was mixed changes in a dark colour when the iodine is mixed. This was very clear when the iodine was placed into the second glass. The iodine changed colour when in came in touch with the starch. However, you did not see the iodine mixture change colour. With some magic, the iodine went through the wall into the sealed plastic bag, and the corn-starch was not able to pass into the iodine. Corn-starch molecules are big, in comparison to the iodine, so they can pass through, the holes are too small to allow corn-starch molecules to go through they are kept behind inside the plastic sealed bag, therefor the iodine that was mixed stayed its original colour.

So, the facts that we have learnt is that diffusion and osmosis are two different ways the plant cells get their nutrients to grow big and strong, and osmosis is the process by which liquids pass through the walls of cells Reference - The Everything Kids' science experiments book

Watch this for an even better explanation

Source

signature

Team South Africa banner designed by @bearone