An inquiry-driven physical science unit investigating the properties of matter, reversible phase changes, physical alterations, and chemical reaction indicators through hands-on everyday investigations.
Not simple paint mixing! Two clear liquids combining into a vivid yellow, or shiny copper pennies turning greenish as patina forms.
4. Precipitate Formation or Odor
A solid powder (precipitate) falls out of solution when two clear liquids mix, or an entirely new smell (like sour curdled milk) emerges.
Core Vocabulary Focus
Term
Scientific Definition
Context Clue
Reactants
Starting substances before chemical change occurs.
Left side of equation.
Products
Brand-new substances formed after the reaction.
Right side of equation.
Precipitate
An insoluble solid that forms from mixing liquid solutions.
Cloudy solid settling down.
Exothermic
A reaction that releases thermal energy into surroundings.
Campfire, hand warmers.
Endothermic
A reaction that absorbs thermal energy from surroundings.
Cold packs, vinegar + soda.
Ambiguity Check: When you add red food coloring to water, it turns red. Is this a chemical change? Explain why or why not.
Unit 1: Matter & Change Page 2 of 3
Assessment & Application
Everyday Case Files & Comprehension
Name:
Part A: Everyday Case File Classification
Scenario
Type (P / C)
Scientific Justification
1. An egg is fried on a hot skillet until the clear liquid turns solid white.
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2. An aluminum soda can is crushed flat with a foot.
[ ]
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| 3. Fireworks explode in the sky, producing bright green light and a boom. | [ ] |
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| 4. Wet clothes hang in the breeze until they are completely dry. | [ ] |
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| 5. Milk left on the counter for a week curdles into sour lumps. | [ ] |
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Part B: Concept Check
6. Which is a definitive sign of a chemical reaction?
(A) Liquid turns to gas by boiling
(B) Solid dissolves in water
(C) Formation of a new precipitate
(D) Material is cut into halves
7. During any chemical reaction, total mass must:
(A) Always decrease as energy is lost
(B) Remain exactly conserved
(C) Increase as new bonds form
(D) Depend on room temperature
Part C: Evidence-Based Scientific Analysis
8. Open vs. Closed System: When wood burns in a fireplace, the ash left behind weighs much less than the original log. Explain how this still obeys the Law of Conservation of Mass.
9. Critical Distinction: Explain why water boiling in a pot produces bubbles (a physical change), whereas baking soda mixed with vinegar produces bubbles (a chemical reaction).
Unit 1: Matter & Change Page 3 of 3
Physical or Chemical?
Case A is Physical (reversible phase shift). Case B is Chemical (new sugars & aroma compounds produced).
Mastery Summary 05 / 05
Your 4-Point Detective Checklist
1. Bubbles
New gas generated
2. Color
Unexpected change
3. Energy
Heats up or chills
4. New Solid
Precipitate forms
Ready for hands-on testing in Lesson 3: Kitchen Chemistry Lab!
Claim (State your direct answer clearly):
Evidence (Provide specific observations and data recorded during the lab):
Reasoning (Connect evidence to chemical principles: new bonds, gas formation, thermal energy):
Mass Mystery: If you weighed the open cup before and after the reaction in Station 1, the scale reading drops by 1.2 grams. Where did those 1.2 grams go?
Page 2 of 2
Page 1 of 2 • Teacher Reference Manual
Answer Keys & Exemplars
Master Solutions & Rubrics
All Lessons • Answer Key
Lesson 1: State Shifters Key (Q1–Q6)
Q1: (B) Gas particles move rapidly and overcome bonds. | Q2: (B) Definite physical volume.
Q3: (C) Gain kinetic energy and spread far apart.
Q4 (Hot Oven Air): High thermal energy means gas particles move at high velocity, expanding rapidly to equalize pressure when the door opens.
Q5 (Windshield Frost): Surrounding humid air; water vapor transitions directly from gas to solid (deposition).
Q6 (Freezing Mass): Exactly 250 grams; mass is conserved because particle count remains identical.
Lesson 2: Change Detectives Key (Q1–Q9)
1. Fried egg: C (protein bonds denature).
2. Crushed can: P (shape altered only).
3. Fireworks: C (combustion, light, gas).
4. Drying clothes: P (evaporation).
5. Curdled milk: C (acid precipitating curds).
Q6: (C) Formation of a new precipitate.
Q7: (B) Remain exactly conserved.
Q8 (Fireplace Ash): Unaccounted mass escaped as \(CO_2\) and steam; system obeys conservation.
Q9 (Boiling vs Vinegar): Boiling = phase change without bond breaking; vinegar+soda = chemical synthesis of \(CO_2\).
Lesson 3: Lab CER Exemplar
Claim: Combining vinegar and baking soda is a chemical reaction that creates new substances.
Evidence: Vigorous bubbling occurred without external heating, gas escaped, and the cup temperature dropped by 3–5°C.
Reasoning: Release of carbon dioxide gas and thermal energy absorption (endothermic) demonstrate that starting bonds broke to yield sodium acetate, water, and \(CO_2\).
Support: Use sentence frames for CER explanations; highlight keywords (mass, bond, state) in reading.
Extension: Challenge students to calculate the mass of carbon dioxide produced in Station 1 using an electronic balance.
