Im not sure if you can help me with this but...?

Question

I was asked to draw a cooling graph of water as it passes from 20C to -20C.

I don't know how to? if you could try to explain or give me a site that will it would be GREATLY appreciated! ;)

Answer 1

when water cools it does it at a consistent rate (assuming the air around it is a consistent temperature)

so then in a graph this would be a straight line going from high on the left to low on the right

but a funny thing happens when it gets to the freezing point. the line would be horizontal for a short bit of time because to go from water at 0 degrees celsius to ice at 0 degrees celsius it requires more time then just straight cooling. after it turns to ice the rate of cooling would again be a negative slope on your graph but probably at a lesser slope. I think ice cools slower than water

20-0.1 negative slope on your graph

0.1 to -0.1 horizontal line

-0.1 - -20 negative slope on your graph

I hope this helps

Answer 2

1) Draw your Temperatures on the Y axis of a millimetric coordinates graph: from +20 to -20º going thru 0 in spaces of 5º 2) Put your minutes on the X axis of same starting from 0 to as long as it takes in spaces of 2 or 3 minutes 3) Heat 1 liter of water up to 20º 4) Put it in the freezer 5) Measure its Temp. every 2 or 3 minutes and put the result as a dot on your graph. 6) When the temp reaches -20º put the result on your graph and unite all your dots with a continuous line.