We have done three water experiments here, to demonstrate Air Pressure effect on Water and effect on light path traversal when it passes through water glass.
Experiment 1 – Light Refraction when it passes through water glass
Make and place arrows pointing to left, just before glass of water. When you see through the water glass, arrow points towards right. Why does it happen? Light travels from the air, through the glass, then through the water and again through the back of the glass, and then back through the air, before hitting the arrows. It changes speed when the medium changes and thus the direction of light also changes. This gives us an illusion that the arrows are reverse. Try more by moving glass backward and forward to see what happens, and try to find out 🙂
Experiment 2 – Effect of Air Pressure via a balloon stuck to water bottle
Make a hole in water bottle and put straw inside it. Fill the bottle and blow a balloon. Cover the bottle opening with blown balloon and the water starts coming out of straw, WHY? Well, the air inside balloon puts pressure on water and hence the water is pushed out of the straw.
Experiment 3 – Effect of Air Pressure on a water bottle with hole
What if you make a hole in water bottle and close the lid? You think water will come out of bottle right? Well no, the water doesn’t comes out from the bottle. But if you open the lid, water starts coming out from the hole. WHY? This is because when you open the lid, air outside the bottle applies pressure on the bottle from the top. That would make sure the water is forced to come out from small hole. When the lid is closed, there is no air pressure from the top and hence no water comes out.
Its always fun and easy to learn science with practical experiments. So watch this video & try to do these water experiment demonstrating effect of Air Pressure & Light Refraction.