Physical and Chemical changes | Viviana Merino | Live - Free Printable

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 (wood and graphite) remains the same.
- 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).
- 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 unchanged.
- 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 the same.
- Physical Change.

6. Burning Wood:
- Burning wood involves a chemical reaction where wood combines 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 substances with different properties.
- 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.}
}