1. Changes Physical Reversible Irreversible Chemical EXAMPLES?
The world around us (matter) is always in a a state of flux.
All changes involve some form of energy transfer.
Changes
Physical
Reversible
Irreversible
Chemical
EXAMPLES?
Atoms are constantly rearranging
Cook an egg
Eat food, gain energy, digest it poop
Mountains come and go
Grand Canyon –ice ages
Weather systems hurricanes etc.
Cooking
Rusting
Fireworks

2. Physical Changes Aluminum Aluminum Aluminum
The internal composition of something does not change. It remains the same chemically.
Examples: Ripping paper, crushing a can, cutting hair, breaking chalk, molding Play-Doh cracking an egg.
Aluminum foil is made up of aluminum atoms. Tearing aluminum foil in half still results in aluminum atoms
Rrip paper
Rip open a bag of chips
Rip student notebook
Fake homework from azzarra
Pretend to cut somone’s hair
Aluminum
Aluminum

4. Two Types of Physical Changes
Irreversible Physical Change: something that cannot be undone. For example, you cannot uncrack an egg or uncut hair.
Reversible physical change: a change that can be reversed. Phase changes are reversible. Ice that melts can be refrozen.

5. Phase Changes are Physical Changes
Whether solid in the form of ice, as a liquid or as a gaseous vapor, water is always H2O.
Water always has a ratio of two hydrogen atoms to one oxygen atom regardless of the form it is in.
Phet App: States of Matter O H
Show water, show neon

6. EVAPORATION CONDENSATION Physical Changes DEPOSITION MELTING FREEZING
GAS
CONDENSATION
LIQUID
Physical Changes
DEPOSITION
MELTING
FREEZING
SOLID
SUBLIMATION

7. Burn Burn Burn
Play Ellie Goulding Song
Burn students notebook

8. Something New forms at the Molecular Level
Chemical Changes
One or more substances changes into something new. The internal properties of a substance change.
Example: Burning Paper (combustion in general), digestion of food, rusting, fireworks exploding, cooking an egg, any chemical reaction.
Light sparkler
Something New forms at the Molecular Level

9. Combustion of Steel Wool
4Fe+ 3O2---> 2Fe2O3 O O Fe Fe Fe Fe Fe + Fe  O O Fe Fe O O O O O O O O
Burn Steel wool
2H2 + O2  2H2O
Formation of water
2H2O  2H2 + O2
Electrolysis of water
4 iron atoms (4Fe) combine with 6 oxygen (3O2) atoms to form two units of iron oxide (2Fe2O3)

10. +  Electrolysis of Water 2H2O + electricity  2H2 + O2
Hoffman apparatus…show this
2 water molecules (2H2O) split into 4 hydrogen atoms (2H2) and 2 oxygen atoms (O2),

11. Hoffman Apparatus: Electrolysis
Electrocuting water (H2O) causes its bonds to break and it separates into H2 and O2
This is a CHEMICAL CHANGE, something new forms.
H2O + Electricity  H2 + O2
TheoryA Hoffman voltameter, or Hoffman apparatus, uses electrolysis to produce hydrogen and oxygen gasses from water. By passing a DC electric current through the water (with an electrolyte solute to improve conductivity), energy is put into the water – enough so that the chemical bonds within H2O are broken and it splits and reforms into H2 and O. The O then finds another O that split from another molecule of water and forms O2. Hydrogen gas (H2) forms as bubbles at the negative cathode and oxygen gas (O2) at the positive anode, so if the two electrodes are kept slightly separate, the two gasses can be collected separately and used for good, or evil, depending on personal preference.

12. CHEMICAL OR PHYSICAL CHANGE?
Baking Soda and Vinegar
Chemical or Physical
Cooking an Egg
Ripping Paper
Lighting a Match
C₃H₈O molecules evaporating
Ice Melting
Mixing Baking soda and vinegar
Getting a suntan
Show Video
Talk about rockets

13. 5 Clues a Chemical Change might have taken Place
Transfer of Energy (temperature change…endothermic/exothermic reactions)
Color Change (ex. Fruit changes color over time, this is a chemical change)
Formation of a Precipitate (a solid particle when two solutions are mixed)
Production of Gas (gas bubbles indicate a chemical change might have occurred)
Production of an Odor (an egg rotting, smell of the atmosphere after a lightning storm)
Lab
1) Endothermic and Exothermic Lab