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Wednesday, March 11, 2015

Moving air

11th March, 2015
We know that air is all around us.  We are glad that we have air to help us:
Teacher had an "empty" bottle.
We thought we could blow up a balloon inside a bottle, so we tried hard.
We decided that this was impossible because we were trying to put more air into a bottle that was already FULL.....of air!
But, hang on...
Teacher gave us another bottle and this time it was easy to blow up the balloon.
Very strange!  We had to guess why we could blow up the balloon this time.
After a few guesses we decided that there must be holes in the bottle, which let the air out when the new air (in the balloon) filled the bottle.  Yep, we could feel the air escaping.
Next teacher gave us a bottle with cold water in it.  She emptied out the water.
We could now get the bottle to talk to us by putting our warm hands around the bottle.
This warmed the air in the bottle and because warm air takes more space than cold air, the warm air escaped making the bottle talk!
Next we tried making an air toy - getting the box to open its lid using trapped air (pneumatics).
We tried a pump but the air kept escaping (until we trapped the air in a plastic bag, which we could easily blow up using a pump or a straw).
Lastly we tried moving different objects (without touching them).
We tried blowing (with our mouths or a straw), dropping them off a ramp, stamping near them so the vibrations moved them (or not), pulling fabric from under them.
We ran a fair test by starting all the objects on the same line, using one child to blow each in turn as hard as he could, and we saw how far each one travelled.
We recorded the results,
and we ordered the objects from the one that moved furthest to the one that did not move at all.
We have learned quite a lot about air today.

12th March 2015
 We began today's talk by discussing bubbles.
We looked at the colours in the bubbles, and watched as the bubbles changed from rainbow coloured to a silver colour before bursting.
We are able to move bubbles by blowing them or by fanning the air around or under the bubbles.
We will have a bubble day outside in the last term where we will really get to find out more about how bubbles fly and then burst.
Yesterday we made one pneumatic (trapped air) toy.  Today we made another.
For this we needed two syringes and a piece of tubing (like the type that are in fish tanks).
The syringes looked empty but we know that in fact each one was full (of air) as was the tubing.
Some of us use syringes at home when we are taking Calpol or antibiotics, and teacher explained that the doctor uses them too, to give injections of medicine into your muscles if you need them.
We joined two syringes together with the tubing.  Air is trapped between them.  When you push one plunger on the syringe the plunger on the other syringe pops out, and when you pull one plunger, the plunger on the other syringe pushes in.
Here's the mouse in his hole toy we made that using trapped air (pneumatic toy).

We also talked about different machines that use air.
Aeroplanes, helicopters, hot air balloons and gliders use air to fly.
Parachutes trap air so that you can slow down if you jump from a plane, and diggers and dumpers use pneumatics to get their buckets to rise and lower.
We had a hard job guessing which kind of boat (apart from a yacht) uses air to travel on.
We discovered that hovercrafts actually float on a layer of air when then sail.
Here are pictures of  hovercrafts.
Teacher had an old CD and she put the top of a water bottle on to it with blue tack.
We thought that if you blow into the bottle top that the air will go through the top and under the CD.  This didn't work very well because the person blowing the air would have to stay with the mini hovercraft all the time.
We decided that a balloon would work so much better!
We tried pushing the CD and balloon on the floor.  It didn't travel too far with a small push.  We remembered that it was friction (rubbing against the floor) which slowed it down.
As a hovercraft the difference was amazing.
Just a tiny tap got the hovercraft zooming across the floor.
We were sooooooooooo impressed.
We are really amazed at all we have learned about air, and we have promised teacher to try and make a toy at home that will use air to move.  We might even let our parents help us to make them!
Teacher can't wait to see the results!

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