Lesson 50 covers:

• Elementary Level: Changes in Matter (Melting and Freezing)
• Mid Level: Light and Reflection
• High Level: Chemical Reactions and Equations

Elementary Level (Kinder to Grade 2)

Subject: Changes in Matter (Melting and Freezing)

Alignment with Standards:

• Next Generation Science Standards (NGSS):
  • 2-PS1-4: Construct an argument with evidence that some changes caused by heating or cooling can be reversed and some cannot.
• Common Core State Standards (CCSS) Connections:
  • CCSS.ELA-LITERACY.SL.1.1: Participate in collaborative conversations.
  • CCSS.ELA-LITERACY.SL.1.5: Add drawings or other visual displays to descriptions.

Lesson Objectives:

By the end of this lesson, the student will be able to:

1. Define melting (solid → liquid) and freezing (liquid → solid).
2. Observe and describe how heat causes ice to melt and cold causes water to freeze.
3. Record observations using simple drawings or words.

Materials Needed:

✅ Ice cubes
✅ Small bowl or plate
✅ Warm water (for melting demonstration)
✅ Freezer-safe container (for freezing demonstration)
✅ Timer or clock
✅ Paper and crayons/markers for recording observations
✅ Magnifying glass (optional)

Lesson Activities:

1. Introduction (10 minutes)

• Engage: Show an ice cube and ask:
  • “What happens when we leave ice out on the table?”
  • “Can we turn water back into ice? How?”
• Explain: Introduce key terms—solid, liquid, melting, freezing.
• Image Prompt: Show a simple diagram of the water cycle (ice → water → ice).

2. Ice Melting Experiment (15 minutes)

• Procedure:
  1. Place an ice cube on a plate.
  2. Observe and time how long it takes to melt at room temperature.
  3. Speed up melting by pouring a little warm water over another ice cube.
  4. Discuss: “Which melted faster? Why?”
• Record Observations: Draw before/after pictures.

3. Water Freezing Observation (15 minutes)

• Procedure:
  1. Pour water into a small container.
  2. Place it in the freezer and check every 10 minutes.
  3. Discuss changes: “What happened to the water? Why?”
• Optional: Compare freezing times with different container sizes.

4. Wrap-Up Discussion (10 minutes)

• Review Key Concepts:
  • “What makes ice melt?” (Heat)
  • “What makes water freeze?” (Cold)
• Real-World Connection:
  • “Where do we see melting/freezing in everyday life?” (Popsicles, snow, ice cream)
• Exit Question: “If we left this melted ice outside in winter, what would happen?”

Assessment:

• Informal: Verbal responses during discussion.
• Formative: Student’s drawings/labels showing melting and freezing.

Extension Activities (Optional):

🔹 Predict & Test: Does salt make ice melt faster? (Sprinkle salt on one ice cube.)
🔹 Art Connection: Draw a sunny day (melting) vs. a snowy day (freezing).

Mid Level (Grade 3 to 5)

Subject: Light and Reflection

Alignment with Standards:

• Next Generation Science Standards (NGSS):
  • 4-PS4-2: Develop a model to describe that light reflecting from objects and entering the eye allows objects to be seen.
  • 4-PS3-2: Make observations to provide evidence that energy can be transferred by light.
• Common Core State Standards (CCSS) Connections:
  • CCSS.ELA-LITERACY.SL.4.1: Engage in collaborative discussions.
  • CCSS.ELA-LITERACY.W.4.2: Write informative/explanatory texts (lab reports).

Lesson Objectives:

By the end of this lesson, the student will be able to:

1. Explain that light travels in straight lines and can be reflected.
2. Conduct experiments using mirrors to demonstrate reflection.
3. Predict and test how changing angles affect reflected light.
4. Record observations and draw conclusions in a simple lab report.

Materials Needed:

✅ Small mirrors (2-3)
✅ Flashlight (or laser pointer, with safety precautions)
✅ White paper or poster board
✅ Ruler or straightedge
✅ Protractor (optional, for angle measurement)
✅ Small objects (e.g., toy figurine, coin)
✅ Dark room or shaded area (for better light observation)
✅ Science journal or worksheet for recording observations

Lesson Activities:

1. Introduction (15 minutes)

• Engage: Ask:
  • “How do we see objects?”
  • “Why can you see yourself in a mirror but not in a piece of paper?”
• Explain: Discuss key concepts—light travels in straight lines, reflection, angle of incidence = angle of reflection.
• Image Prompt: Show a diagram of light reflecting off a mirror (with labeled angles).

2. Mirror Reflection Experiments (30 minutes)

Experiment 1: Basic Reflection

• Procedure:
  1. Place a small object in front of a mirror.
  2. Shine a flashlight toward the mirror.
  3. Observe where the light reflects and discuss why.
  4. Trace the path of light with a ruler (light source → mirror → reflected spot).

Experiment 2: Changing Angles

• Procedure:
  1. Hold a mirror at different angles while shining a flashlight.
  2. Predict where the light will reflect before testing.
  3. Use a protractor to measure angles (optional for advanced learners).

Experiment 3: Double Mirror Reflection (Extension)

• Procedure:
  1. Place two mirrors facing each other at different angles (e.g., 90°).
  2. Place an object between them and observe multiple reflections.
  3. Discuss: “Why do we see more reflections when mirrors face each other?”

3. Wrap-Up Discussion (15 minutes)

• Review Key Concepts:
  • “How does light travel?” (Straight lines)
  • “What happens when light hits a mirror?” (Reflects at the same angle)
• Real-World Connection:
  • “Where do we see reflections in everyday life?” (Windows, water, glasses, telescopes)
• Exit Question: “If you wanted to reflect light around a corner, how would you position the mirrors?”

Assessment:

• Informal: Participation in experiments and discussion.
• Formative: Lab report or drawn diagrams showing light reflection paths.

Extension Activities (Optional):

🔹 Periscope Making: Construct a simple periscope using mirrors and cardboard.
🔹 Shadow vs. Reflection: Compare how shadows (blocked light) differ from reflections (bounced light).
🔹 Writing Connection: Explain how mirrors help in telescopes or car rearview mirrors.

High Level (Grade 6 to 8)

Subject: Chemical Reactions and Equations

Alignment with Standards:

• Next Generation Science Standards (NGSS):
  • MS-PS1-2: Analyze and interpret data on the properties of substances before and after chemical reactions.
  • MS-PS1-5: Develop and use a model to describe how the total number of atoms is conserved in a chemical reaction.
• Common Core State Standards (CCSS) Connections:
  • CCSS.ELA-LITERACY.RST.6-8.3: Follow multistep procedures in scientific experiments.
  • CCSS.ELA-LITERACY.WHST.6-8.2: Write informative/explanatory texts (lab reports).

Lesson Objectives:

By the end of this lesson, the student will be able to:

1. Identify five signs of a chemical reaction (gas production, temperature change, color change, precipitate formation, odor change).
2. Conduct experiments with vinegar (acetic acid) and baking soda (sodium bicarbonate) to observe chemical changes.
3. Write a simple balanced chemical equation for the reaction.
4. Explain the Law of Conservation of Mass in the context of the experiment.

Materials Needed:

✅ Baking soda (sodium bicarbonate)
✅ Vinegar (acetic acid, 5% solution)
✅ Measuring spoons & cups
✅ Clear plastic cups or beakers
✅ Balloon (for gas collection experiment)
✅ Thermometer (optional, for temperature measurement)
✅ Matches/lighter & candle (teacher demonstration only)
✅ Safety goggles & gloves
✅ Science notebook & pen/pencil

Lesson Activities:

1. Introduction (15 minutes)

• Engage: Ask:
  • “What happens when you mix vinegar and baking soda? Is this a physical or chemical change?”
  • “How do you know if a chemical reaction has occurred?”
• Explain: Introduce the five signs of chemical reactions and discuss reactants vs. products.
• Image Prompt: Show a molecular diagram of the reaction:
  NaHCO₃ + HC₂H₃O₂ → CO₂ + H₂O + NaC₂H₃O₂

2. Hands-On Experiments (40 minutes)

Experiment 1: Classic Baking Soda & Vinegar Reaction

• Procedure:
  1. Mix 1 tbsp baking soda + ¼ cup vinegar in a clear cup.
  2. Observe bubbling (gas production) and temperature change (endothermic reaction).
  3. Discuss: “What gas is produced? How could we test for it?”

Experiment 2: Balloon Inflation (Gas Collection)

• Procedure:
  1. Place 2 tbsp baking soda in a balloon.
  2. Pour ½ cup vinegar into a bottle.
  3. Stretch the balloon over the bottle’s mouth, then dump in the baking soda.
  4. Observe CO₂ gas inflating the balloon.

Experiment 3: Flame Test (Teacher Demo Only)

• Procedure:
  1. Light a candle.
  2. Pour CO₂ gas (from the reaction) near the flame.
  3. Observe: “Why does the flame go out?” (CO₂ is denser than air and displaces oxygen.)

3. Data Analysis & Discussion (20 minutes)

• Balanced Chemical Equation Practice:
  • Write: NaHCO₃ + HC₂H₃O₂ → CO₂ + H₂O + NaC₂H₃O₂
  • Count atoms on both sides to show conservation of mass.
• Real-World Connection:
  • “Where do we see chemical reactions in daily life?” (Cooking, rusting, digestion)
• Exit Question: “If you used 10g of baking soda, how much CO₂ should be produced?”

Assessment:

• Informal: Participation in experiments and discussion.
• Formative: Lab report including:
  • Observations of chemical changes.
  • Balanced chemical equation.
  • Explanation of conservation of mass.

Extension Activities (Optional):

🔹 Quantitative Experiment: Measure mass before/after reaction to prove conservation of mass.
🔹 pH Testing: Compare vinegar’s acidity before/after the reaction.
🔹 Research Project: Explore real-world uses of CO₂ (fire extinguishers, carbonation).