Physical vs Chemical Worksheet

Name: _______________________ Date: _______________________

Part 1: Definitions

1. In your own words, define a physical change.
   
   
   
   
   
   
2. In your own words, define a chemical change.
   
   
   
   
   
   

Part 2: Classify the Changes

Read each scenario below. Write Physical or Chemical on the line.

1. Melting ice cream on a cone: _______________________
   
   
   
2. Burning a candle’s wax: ___________________________
   
   
   
3. Dissolving salt in water: _________________________
   
   
   
4. Food turning brown when exposed to air: _____________
   
   
   
5. Cutting a piece of fabric: _________________________
   
   
   
6. Mixing baking soda and vinegar (fizzing): __________
   
   
   

Part 3: Sorting Activity

Below are six changes. List the numbers of the changes under the correct type.

Changes:

1. Sugar dissolving in coffee
2. Iron rusting
3. Water freezing into ice
4. Leaves changing color in autumn
5. Shredding a piece of paper
6. Wood burning in a fireplace

Physical Changes:
___, ___, ___

Chemical Changes:
___, ___, ___

Part 4: Matching Indicators

Column A shows common indicators of chemical changes. Column B defines each indicator. Match by writing the letter from Column B next to the number in Column A.

Column A:

1. Gas formation
2. Color change
3. Temperature change
4. Precipitate formation

Column B:
A. A solid that forms and settles out of a liquid mixture
B. Release or absorption of heat (feels hot or cold)
C. Bubbles or fizzing appear when substances react
D. Substance turns a different color without mixing dyes

1. ___ 2. ___ 3. ___ 4. ___
   
   
   
   
   

Part 5: Short Answer

Explain why melting butter on toast is considered a physical change and not a chemical change.

Part 6: Create Your Own Example

Describe one example of a chemical change you have seen or can imagine. Explain which indicator(s) tell you its a chemical change.

Physical vs Chemical Worksheet Answer Key

This answer key provides correct responses and detailed explanations to help with grading and student understanding. It corresponds to the Physical vs Chemical Worksheet.

Part 1: Definitions

1. In your own words, define a physical change.
   Answer: A physical change is a change that alters the form, appearance, or state of a substance without creating a new substance (its chemical composition remains the same).
   Explanation: Key ideas include change of state (solid, liquid, gas), shape, or size, but no new chemical bonds are formed or broken.
2. In your own words, define a chemical change.
   Answer: A chemical change is a change in which one or more new substances with different chemical properties are formed.
   Explanation: Indicators include gas production, color change, temperature change, or precipitate formation, showing that chemical bonds have been broken and new ones formed.

Part 2: Classify the Changes

For each scenario, write Physical or Chemical, and explain why.

1. Melting ice cream on a cone: Physical
   • Only a change of state (solid to liquid); the sugar, fat, and water remain the same substances.
2. Burning a candle’s wax: Chemical
   • Combustion produces new substances (carbon dioxide, water vapor) and releases heat and light.
3. Dissolving salt in water: Physical
   • Salt ions disperse but no new substance forms; salt can be recovered by evaporating water.
4. Food turning brown when exposed to air: Chemical
   • Oxidation reactions create new brown pigments (e.g., in apples), indicating new chemical compounds.
5. Cutting a piece of fabric: Physical
   • Only the shape and size change; the fabric’s fibers and chemical makeup stay the same.
6. Mixing baking soda and vinegar (fizzing): Chemical
   • Fizzing indicates carbon dioxide gas formation; new substances (CO₂, sodium acetate) are produced.

Part 3: Sorting Activity

List the numbers of the changes under the correct type and explain your grouping.

Physical Changes: 1, 3, 5
• (1) Sugar dissolving in coffee – no new substance, just dispersion.
• (3) Water freezing into ice – state change only.
• (5) Shredding a piece of paper – shape/size change only.

Chemical Changes: 2, 4, 6
• (2) Iron rusting – new compound (iron oxide) forms.
• (4) Leaves changing color in autumn – pigment breakdown and new compounds form.
• (6) Wood burning in a fireplace – combustion produces new gases and ash.

Part 4: Matching Indicators

Match each indicator of a chemical change (Column A) with its definition (Column B):

1. Gas formation | C. Bubbles or fizzing appear when substances react | 1 → C
2. Color change | D. Substance turns a different color without mixing dyes | 2 → D
3. Temperature change | B. Release or absorption of heat (feels hot or cold) | 3 → B
4. Precipitate formation | A. A solid that forms and settles out of a liquid mixture | 4 → A

Explanation: Each match shows a common sign that a chemical reaction has occurred, distinguishing it from mere physical mixing.

Part 5: Short Answer

Explain why melting butter on toast is considered a physical change and not a chemical change.
Answer: Melting butter only changes its state from solid to liquid. The chemical composition of the butter (its fats and oils) remains unchanged, and no new substances are formed.
Key Point: Physical changes involve state or form changes without altering molecular structure.

Part 6: Create Your Own Example

Sample Student Response:
Example of a Chemical Change: Iron rusting on a bicycle chain.
Indicators: Color change from silver to reddish-brown (new iron oxide), formation of a solid layer (precipitate), and the process is irreversible without chemical treatment.
Explanation: Rusting produces a new substance (iron oxide) and shows classic signs of a chemical reaction.

Teacher Note: Look for student examples that identify at least one clear indicator (gas, color change, precipitate, or temperature change) and explain why it shows a chemical change.

End of Answer Key for Physical vs Chemical Worksheet. Good luck with grading and reinforcing these concepts!

Fizz or Not Activity

Objective: Students will quickly identify fizzing as a key indicator of chemical changes and practice sorting reactions based on observable gas formation.

Materials:

• Index cards with 8–10 reaction descriptions (e.g., “Baking soda + vinegar,” “Salt + water,” “Iron nail in water,” “Alka-Seltzer in water,” etc.)
• Two large bins or hula hoops labeled Fizz and Not Fizz
• Tape or Velcro to attach cards
• Safety goggles (for any live demo cards)
• Timer or stopwatch

Time: 10 minutes

Prep (2 minutes):

• Write each reaction scenario on an index card.
• Label one bin/hoop “Fizz” and the other “Not Fizz.”
• Mix the cards and place them face down.

Activity Steps:

1. Warm-up (1 minute)
   • Quickly review with the class: “What does fizzing tell us about a reaction?” (Answer: gas formation → chemical change.)
2. Card Sort (5 minutes)
   • Divide students into small groups of 3–4.
   • Give each group a stack of reaction cards.
   • On “Go,” groups race to place each card into the correct hoop/bin: Fizz if they expect bubbling/gas, Not Fizz if they expect no gas.
   • Encourage kinesthetic movement: students can run cards and stick them in, then return for the next.
3. Quick Demo Cards (2 minutes)
   • For two cards chosen by teacher (e.g., Baking soda + vinegar and Salt + water), perform a live mini-demo at the front.
   • Ask observers: “Does it fizz? Why or why not?”
4. Class Debrief (2 minutes)
   • As a class, review any cards that groups disagreed on.
   • Record correct sorting on the board under headings Fizz → Gas Formed and Not Fizz → No Gas.
   • Reinforce: fizzing is a visible sign of a chemical change (gas formation).

Follow-Up Questions:

• Which mixtures could be reversible physical changes even if they fizzed? (e.g., Alka-Seltzer in water → gas escapes but solids dissolve physically before reaction.)
• How might you test another indicator (color or temperature change) in a similar sorting game?

Extension:

• Challenge advanced groups to write their own reaction cards including other indicators (e.g., color change, precipitate formation) for a later “Change Detectives” sorting activity.

Reflect & Share Cool Down

Take the last 5 minutes to reflect on today’s lesson. Write your responses in the spaces provided, then turn to a partner and share your thoughts.

1. Name one physical change you observed today and describe what you saw:
   
   
   
   
   
   
2. Name one chemical change you observed today and describe the indicator(s) (e.g., fizzing, color change):
   
   
   
   
   
   
3. What’s one new thing you learned about how matter interacts?
   
   
   
   
   
   
4. What question or wonder do you still have about physical or chemical changes?
   
   
   
   
   
   
5. How might you see or test for physical vs. chemical changes outside of class?
   
   
   
   
   
   
   
   
   
   
   

Share & Discuss (2 minutes)

• Turn to a partner and share at least two of your responses.
• Listen for similarities and note any different observations or questions.
• Be prepared to share one interesting insight or question with the whole class.