Starter: Practice: Agree or disagree with each of these statements: Application: Connection/ Exit:
Starter:Starter: Agree or disagree with each of these statements. 1. Mixing powdered drink mix with water causes a new substance to form. 2. If you combine two substances, bubbling is a sign that a new type of substance may be forming. 3. If you stir salt into water, the total amount of matter decreases.
Starter: Practice: Agree or disagree with each of these statements: Application: Connection/ Exit:
Matter undergoes changes all of the time. Practice:Practice:
There are two types of changes: chemical physical &
Physical changes:
Physical changes occur when the appearance of a substance changes…
chemically …but chemically the substance is the same.
The individual molecules do not change.
Examples of physical changes are, melting, freezing,
or changing size or shape.
A physical change also occurs when substances are…
mixed and something dissolves…like making salt water or Kool- aid.
The water, salt and sugar still keep their original properties and the substances can be separated again.
Chemical Changes
A chemical change occurs when the atoms making up matter rearrange..
to form a new substance with new properties.
This usually occurs during a chemical reaction.
Evidence of a chemical change:
Production of a gas.
bubbles fizzing foaming smoke odor
color change *not all color changes are chemical!
A different color appears
*not all color changes are chemical!
Formation of a precipitate
cloudiness foggy solid at bottom of container
Change in heat or light energy
Sparks explosion glowing
temperature increases or decreases
These are only clues…
…a chemical change has not actually taken place unless matter has changed into a new substance.
Some common examples of chemical changes include…
Rusting…
Tarnishing…
Burning…
Cooking…
Digesting…
If you have the chemical equation, you can tell if a chemical change has taken place by…
Looking to see if the products in the equation are….
different from the reactants.
P C Application: Place a P in the blank if it is a physical change and a C in the blank if it is a chemical change. 1.______ An iron nail rusting. 2.______ Baking cookies. 3.______ Chopping wood 4.______ Digesting food for energy 5.______Ice melting.
Connection/Exit: 1.Which of Spangler’s experiments shows chemical changes? 2.What evidence do you see in the video that shows chemical changes?