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Physical ChangeChange in size, shape or physical state

that does not change actual substance

Chemical ChangeOne or more substances change into

new substances with different chemical

propertiesVC – Comparing Physical and Chemical Changes

Energy

The capacity to do work.

All change (physical or chemical) in matter involves energy.

Kinetic Energy – energy due to motion; depends on mass and velocity

Potential Energy – energy due to position or condition

VC – Kinetic Energy

Potential Energy

Law of Conservation of Energy

Energy…• cannot be created or destroyed.• can be transferred from one object to

another.• Can change form (heat,light,electrical,

chemical…).• Total amount of energy in the universe

never changes.

VC – Law of Conservation of Energy

Heat – energy transferred between substances because of their difference in temperature

• Heat always travels from hot substances to cold

• A substance feels hot when your hand absorbs energy from it

• A substance feels cold when your hand loses energy to it

VC - Heat

Temperature – measure of the average kinetic energy of the particles of a substance

• Fahrenheit oF• Celsius + 273 = Kelvin oC• Kelvin – 273 = Celsius K

Specific Heat – amount of energy needed to raise the temperature of 1 g of a substance by 1 oC

• Unique for every substance• Explanation: sunny day at the beach!

VC – Specific Heat Capacity

Endothermic Process – when a substance absorbs energy from its environment• Ice melting (physical change)• cooking food (chemical change)

Exothermic Process – when a substance releases energy into its environment

• Water freezing (physical change)

• Wood burning (chemical change)

Which is endothermic, which is exothermic process?

Scientific Method

The Steps

1. Observe

2. Question

3. Hypothesize

4. Test hypothesis (experiment)

5. Analyze results

6. Draw Conclusions

7. If conclusion supports Hypothesis, share information with other scientists

TheoryAn attempt to explain WHY something

happensBased on multiple observations and

experimentsCan change over time as new

observations or experiments are made

LawExplains WHAT happensBased on multiple observations and

experimental resultsDoesn’t change

VC – Comparing Theories and Laws

Models

A way of showing an object, process, or idea to make it easier to understand

Models are simpler than the object, process, or idea they represent

Accuracy v. PrecisionTurn to page 55