Will the water flow out?

I always aim to explain theories to my students by doing experiments and showing them the evidence.
Last week I did this with my kids and you can do it at home too!

Click here for the video.

1.Fill up a bottle with water.
2. Find a sieve – the kind used for sifting flour, or a piece of gauze or fine wire mesh.
3. Show that water can flow through it with minimal resistance.
4. Ask what will happen if the sieve is placed over the mouth of the bottle and overturned.
Most will guess that the water will still flow out, and be surprised that it doesn’t.
Why doesn’t the water flow out?
– When the water first flows out, a partial vacuum is formed in the air space that is trapped inside the bottle.
– This partial vacuum doesn’t allow the water to move out.
– The water at the mouth stops air from the outside to move into the bottle and neutralising the partial vacuum.
I hope I captured the interest of my students and helped them enjoy the learning progress! smile emoticon