Temperature and States of Matter

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Temperature and States of Matter
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Measuring Temperature Using States Of Matter
COLD
WARM
HOT
Solids can turn into liquids, and liquids can
turn into gasses and back again - depending on
the temperature. So, we can use the effect of
heat on states of matter to measure the
temperature of something.
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Using Gasses To Measure The Temperature
VERY COLD
HOT
For example, a balloon filled with air shrinks as
it gets cold, and expands as it gets hot. This
is a very sensitive way of measuring temperature
BUT its not very accurate because the size of a
balloon also depends on other things like air
pressure!
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Using Liquids To Measure The Temperature
Liquids are less sensitive to temperature changes
but are better than gasses they are hardly
effected by air pressure! Which is why we use
coloured alcohol or mercury in most thermometers!
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The Fahrenheit Scale
The Fahrenheit scale was invented in the early
1700s by G. Daniel Fahrenheit.
The start of the scale is at 0F which is the
temperature of a mixture of equal parts of
water, ice, and salt. And 212F is the top of
the scale which is the boiling point of
water. So the Fahrenheit scale has 212 degrees
in it
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The Celsius Scale
The Celsius scale was invented in 1742 by Anders
Celsius
The start of the scale is at 0C which is the
temperature of the freezing point of water. And
100C is the top of the scale which is the boiling
point of water. So the Celsius scale has just
100 degrees in it!
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Useful Temperatures To Know
Fahrenheit Celsius
Celsius is a scale that is easier to use and
easier to measure
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Colour Changes Can Also Be Used For Measuring
Temperature
Another way of measuring temperature is by using
materials that change colour with temperature.
For very hot temperatures people like blacksmiths
use the way metal changes colour to estimate the
temperature For more normal temperatures liquid
crystal displays can be used
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Fixed Points
What do you think happens to ice and water at 0C
and 100C?
Did you know that at 0C water turns into ice and
ice turns into water but the temperature of a
water ice mixture stays at 0C until all the ice
has become water or all the water has become ice
The same is true at 100C water turns to steam,
but the water stays at 100C until all the water
has turned to steam
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Solid, Liquid And Gas?
Most types of matter have solid, liquid and gas
forms, for example water has ice, water and steam
forms.
BUT some types of matter dont have certain
states, for example dry ice (solid CO2 ) just
goes from solid to gas on heating the solid
DOESNT melt and become a liquid
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Ice Floats On Water!
If you put the solid form of a material into the
liquid form of the same material it will usually
sink to the bottom, but ice is strange as it
actually floats on water!
This is because water is one of the few materials
that expands when it freezes. This property of
water is very important environmentally because
if this didnt happen icebergs would sink to the
bottom of the sea and cause the sea to freeze
over!