How strong is air?

We know that air is all around us but we were wondering if air is very strong?

We tested this by using a bottle and a ping pong ball.

If you fill a bottle with water and then put a ping pong ball on top instead of a cap, what do you think will happen if you turn both up-side down.

Will the ping pong ball fall, causing all the water to splash all over the place?

OR

Will the ping pong ball stay where it is and act as a stopper, keeping all the water in the bottle?

Surprisingly this is exactly what happens.

Why?

The water in the bottle wants to fall to earth (gravity is pulling the water) but the air under the ping pong ball pushes it up against the bottle keeping all the water in the bottle.

UNBELIEVABLE!

Try this yourself at home and be amazed!

Passenger boats

Today we made passenger boats.

We used marla.

A ball of marla just sinks every time but still teacher asked us to try and make a floating boat from a sphere of marla.

We saw how big heavy shells can float if they are the right shape.

We designed boats using a similar shape.

When we could get our boats floating, we loaded them with passengers to see how many passengers each boat could take before it sank.

Bug sprays

We were talking about the different kinds of sprays there are and what each is used for.

Today we made our own sprays.

We needed to use our maths skills for this.

This experiment works only with right angles or acute angles (angles that are smaller than a right angle).  

If we put a straw into a glass of water, the water rises in the straw so that there is air and water in the straw.

If we get another straw and put it against the first straw at a right angle or acute angle then we can blow the air at the top of the straw away.  This makes a vacuum, and the air (and then the water) in the straw rush up to fill the vacuum. When the water reaches the top of the straw it too gets blown by the straw, turning it into water droplets which becomes the spray.

We are delighted to know how sprays work!

Asteroids, craters and the end of the dinosaurs

We were talking about asteroids and how they crash into planets leaving craters.

We saw how different sized asteroids can make different sized craters (we measured the size of the craters in relation to the size of the craters....and plotted these on a graph!)

We saw how the same sized asteroids can make different sized craters (we measured the size of the craters in relation to the height from which the asteroids crashed into the planet....and plotted these on a graph!)

We then talked about how an asteroid crashing to earth could have killed off some of the dinosaurs.  Then some dinosaurs must have been killed by the dust or shock waves from the impact, and finally many many more dinosaurs must have been killed off when the dust and debris from the impact would have blocked the sun's light and heat causing a huge ice age.  This ice age would have meant that some dinosaurs might have died of the cold while others must have starved to death when plants couldn't grow in the cold.

 We found all this extremely interesting!