Changes
in Matter
Ch 1 Sec 3
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Physical property
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Can observe without changing substances
 Color, shape, size density, melting point, boiling point
 Appearance, measure, magnetism
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Physical changes

Kind of substance doesn’t change
 May change state
 Peanuts – peanut butter: still peanuts
 Still the same substance
 Change in state – solid to liquid or liquid to gas =
physical change
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Examples of physical change:
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Sugar dissolved in water (sugar remains in bottom of
the pan after water evaporates)
Bending
Crushing
Breaking chopping
Anything that changes the shape
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Chemical changes

Changes into a new substance (normally can’t get it
back)
 Also called a chemical reaction
 Smell change, foaming, energy, production
 2 or more substances combine to form a totally new
substances
 Iron combines with Oxygen from the air = iron oxide 
rust
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Chemical properties

Tells whether it will change chemically
 Flammable, combustible
 See figure 17 p 24
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Conservation of mass
 Mass before = mass after change
 Matter is not created or destroyed in any
chemical or physical
 Sometimes called the “law of
conservation of matter”
 Must include ALL matter (solid,
liquid, or gas)
 See figure 19 p 25
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Energy – ability to do work or cause change
EVERY chemical or physical change in matter
includes a change in energy
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Bending a paper clip require energy
Ice melting absorbs energy
Candle burning gives off energy
Temperature & thermal energy

Temp. = measure of the avg. energy of random
motion of particles of matter
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Thermal energy = total energy of all particles in
an object
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Thermal energy & temp are NOT the same
 Temp is related to the amount of thermal energy an
object has
 Thermal energy ALWAYS flows form warm to cool
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Thermal energy & changes in matter

Matter changes – most common form of energy =
thermal energy
 Ex. Ice melting
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Endothermic change – energy is TAKEN IN
Exothermic change – RELEASES energy