Changes in Matter
Chapter 2 Section 3
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Physical Change
Any change that alters
the form or
appearance of matter
but does NOT make
any substance in the
matter into a different
substance.
Examples:
Sand Castles
Crushing a Can
Dissolving Sugar in
Water
Changes of State
Matter Occurs in 3
States
Solid
Liquid
These are all physical changes
Gas
Physical Change
• Is there a physical
change when you What could you do separate
dissolve a
the sugar from the water?
teaspoon of sugar
in water?
YES!
Other examples of physical
change:
~ Bending
~ Crushing
~ Chopping
Chemical Change
Change in matter that produces
one or more new substances
s a chemical change (reaction).
Example:
What happens when you pour
hydrogen peroxide on a cut it
breaks down into water and
oxygen gas.
Chemical Change
Two or more substances
can also combine to form
different substances.
A chemical change produces
What do iron metal and oxygen
new
make when they combine?
substances with properties
different from those of the
original substances.
iron oxide (rust)
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Law of Conservation
of Mass
Matter is not created
or destroyed in any
chemical or physical
change.
Mass measures the
amount of matter.
Atoms are not lost or
gained, only
rearranged.
Matter and Thermal
Energy
Energy is the ability to
do work or cause
change.
Every chemical or physical
change in matter includes a
change in energy.
Temperature and
Thermal Energy
Temperature is a measure of the average energy of
random motion of particles of matter.
Warm air outside particles of
gas have greater average
energy of motion that the
particles of air in a cool
building.
Thermal energy is the total energy of all the
particles in an object.
Thermal Energy and
Changes in Matter
When matter changes, the
most common form of
energy released or
absorbed is thermal energy.
Melting of Ice:
Warming hands by a fire:
ENDOTHERMIC CHANGE
EXOTHERMIC CHANGE
(energy taken in by ice)
(energy released by wood fire)
The End