Science - Communicating in Science

We have been working on making observations, describing and comparing them in our learning about how to communicate our scientific thinking.  We are developing knowledge of the vocabulary and symbol systems and conventions and how these are used to communicate ideas and knowledge.

This is what we did:

We placed some water in a tray with some food colouring.
We placed a candle the tray with coloured water.
Miss K said she was going to put a jar over the candle
We then poised a question.

Question:
What will happen to the candle and water?

Most people thought the candle will go out.

Miss K. had written our WALT and Success Criteria on the whiteboard.

WALT:observe, describe and compare physical and chemical properties of common materials and changes that occur when materials are heated or cooled. SC: we can observe and describe what happens to the candle and water we can poise a theory/hypothesis as to why this happens. We can understand a simple formula for a change in chemical state.

Then Miss K. lit the candle.  It went out and as it did the water also rose up the jar!

Then we tried it again to be sure that the same thing would happen.  

Then we did it again with different sized jars and a bottle.  

The same thing happened.  Here's a photo showing what happened.  

We got to have a turn placing the jar over the candle and watching the candle go out and water rise up.

We talked about the chemical names or formula (Scientific Symbol Systems) for candles, water, oxygen and smoke.  Miss K. showed us what it looks like on the whiteboard.

To try and understand why the water was sucked into the jar, we had to understand two different processes:  

1) Burning, two oxygen molecules result in one carbon dioxide molecule and two water molecules.  Not only did the oxygen run out (we knew this would happen), but the water replaced that and more!  So why did the water go in the jar after the candle went out? 

It was hard to understand but, it made sense when Miss K. said, 

"Let's look at the maths".

If we only look at the numbers and not the science names for the chemicals, 2 of (2+4) does not equal 2+2.  But that's what the equation tells us.  So water replaced the missing or burnt gas, the air space in the glass decreased.  It had to be replaced by something. So the water moved up into the glass! 

2) The other reason was that the air warmed up when the candle was burning, but when it went out, the air cooled, which means it takes up less space, so there was even more space (less 'air') in the jar, so the water continues to rise after the flame goes out.

Crazy amount of science from one little experiment!!


 We then had a very quick chat (because we were running out of time) about how we can use this scientific thinking and communication in our every day life.  So much to think about!!