To solve the problem of identifying whether the given scenarios represent
physical changes or
chemical changes, we need to understand the key differences between these two types of changes:
Definitions:
1.
Physical Change:
- A change in which the physical properties (e.g., shape, size, state) of a substance are altered, but the chemical composition remains the same.
- No new substances are formed.
2.
Chemical Change:
- A change in which the chemical composition of a substance is altered, resulting in the formation of new substances.
- New substances with different properties are created.
Analysis of Each Scenario:
#### Top Row:
1.
Fireworks:
- Fireworks involve combustion, where chemicals react with oxygen to produce light, heat, and sound.
- New substances (gases, ash) are formed.
-
Chemical Change
2.
Breaking a Pencil:
- Breaking a pencil only changes its physical form (shape).
- The material of the pencil (wood and graphite) remains unchanged.
-
Physical Change
3.
Baking a Cake:
- Baking involves heating ingredients, causing chemical reactions that create new substances (e.g., carbon dioxide from baking soda reacts with acid to make the cake rise).
- New substances are formed.
-
Chemical Change
#### Middle Row:
4.
Melting Ice:
- Melting ice is a change in state from solid to liquid.
- The chemical composition of water (H₂O) remains the same.
-
Physical Change
5.
Popping Popcorn:
- Popping popcorn involves heating the kernels, which causes the moisture inside to expand and burst.
- While the structure changes, the chemical composition of the corn remains largely the same.
-
Physical Change
6.
Burning Wood:
- Burning wood involves a chemical reaction where wood reacts with oxygen to produce carbon dioxide, water vapor, and ash.
- New substances are formed.
-
Chemical Change
#### Bottom Row:
7.
Boiling Water:
- Boiling water is a change in state from liquid to gas (water vapor).
- The chemical composition of water (H₂O) remains unchanged.
-
Physical Change
8.
Frying an Egg:
- Frying an egg involves heating proteins in the egg, causing them to denature and coagulate.
- This process creates new structures and properties in the egg.
-
Chemical Change
9.
Breaking a Window:
- Breaking a window only changes the physical form (shattering glass).
- The chemical composition of the glass remains the same.
-
Physical Change
Final Answer:
-
Chemical Changes: Fireworks, Baking a Cake, Burning Wood, Frying an Egg
-
Physical Changes: Breaking a Pencil, Melting Ice, Popping Popcorn, Boiling Water, Breaking a Window
\boxed{
\text{Chemical Changes: Fireworks, Baking a Cake, Burning Wood, Frying an Egg} \\
\text{Physical Changes: Breaking a Pencil, Melting Ice, Popping Popcorn, Boiling Water, Breaking a Window}
}
Parent Tip: Review the logic above to help your child master the concept of physical change chemical change worksheet.
