Science Homework

Day 1 (Written) — Chemical Reactions & Equations

1. Combination Reaction: 2H₂ + O₂ → 2H₂O

2. Decomposition Reaction: CaCO₃ → CaO + CO₂

3. Displacement Reaction: Zn + CuSO₄ → ZnSO₄ + Cu

4. Double Displacement Reaction: Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl

5. Redox Reaction: CuO + H₂ → Cu + H₂O

Day 2 (Activity)

Activity: Prepare a chart showing types of chemical reactions with examples.

Day 3 (Written) — Life Processes

• Nutrition: Intake and utilization of food for energy.
• Respiration: Breakdown of glucose in cells to release energy.
• Transportation: Movement of water, minerals, and food throughout the body.
• Excretion: Removal of metabolic waste from the body.

Day 4 (Activity)

Activity: Draw a labeled diagram of the human digestive system on a chart.

Day 5 (Written) — Electricity

1. Find V if I = 2 A, R = 5 Ω. V = I × R = 2 × 5 = 10 V

2. Find I if V = 12 V, R = 4 Ω. I = V/R = 12/4 = 3 A

3. Find R if V = 220 V, I = 0.5 A. R = V/I = 220/0.5 = 440 Ω

4. Series (2 Ω and 3 Ω): R_s = R₁ + R₂ = 5 Ω

5. Parallel (6 Ω and 3 Ω): 1/R_p = 1/6 + 1/3 = 3/6 → R_p = 2 Ω

Day 6 (Activity)

Activity: Make a chart showing a simple electric circuit and its diagram.

Day 7 (Written) — Corrosion and Rancidity

• Corrosion: Gradual destruction of metals by air and moisture (e.g., rusting of iron). Prevention: Painting or oiling.
• Rancidity: Oxidation of fats/oils in food causing bad smell and taste. Prevention: Storing in airtight containers.

Day 8 (Activity) — Rusting Experiment

Observation:

• Test Tube A (Air + Water): Iron nails rusted.
• Test Tube B (Boiled water + oil seal – No air): Iron nails did not rust.
• Test Tube C (Dry air + Anhydrous CaCl₂ – No moisture): Iron nails did not rust.

Conclusion: Both air (oxygen) and water (moisture) are essential for rusting.

Day 9 (Written) — Respiration

• Aerobic vs Anaerobic: Aerobic needs oxygen and releases high energy (38 ATP). Anaerobic happens without oxygen and releases low energy (2 ATP).
• Breathing vs Respiration: Breathing is the physical exchange of gases. Respiration is the chemical breakdown of glucose for energy.

Day 10 (Activity)

Activity: Draw a chart showing the flow chart of respiration (breakdown of glucose).

Day 11 (Written) — Ohm's Law

Relation: Current is directly proportional to potential difference at constant temperature.

Numerical: Device on 220 V line draws 2 A. Find R.

R = V / I = 220 / 2 = 110 Ω

Day 12 (Activity)

Activity: Draw a chart comparing series and parallel circuits with diagrams.

Day 13 (Written) — Chemical Equations

1. Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

2. Respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy

3. Burning Magnesium: 2Mg + O₂ → 2MgO

Day 14 (Activity)

Activity: Prepare a pH scale chart using household items.

Day 15 (Written) — Transportation

• Plants: Xylem transports water upwards. Phloem transports food downwards and upwards.
• Humans: Heart pumps blood through arteries, veins, and capillaries to transport oxygen, nutrients, and waste.

Day 16 (Activity)

Activity: Draw a heart diagram on a chart showing blood flow.

Day 17 (Written) — Electric Power & Energy

• Electric Power: Rate of consuming electrical energy. P = V × I (Watt)
• Electric Energy: Total work done by current. E = P × t (Joule or kWh)

Numerical: 100 W bulb used for 5 hours.

Energy = 0.1 kW × 5 h = 0.5 kWh

Day 18 (Activity)

Activity: Make a poster chart on saving electricity.

Day 19 (Written) — 10 MCQs

1. Gas evolved when zinc reacts with HCl? (Hydrogen)
2. Xylem is responsible for transporting? (Water)
3. SI unit of electric current? (Ampere)
4. Acid in sour milk? (Lactic acid)
5. Breakdown of pyruvate occurs in? (Mitochondria)
6. If wire length is doubled, resistance is? (Doubled)
7. CaCO₃ → CaO + CO₂ is what reaction? (Decomposition)
8. Coating iron with zinc is? (Galvanization)
9. Normal blood pressure? (120/80 mm Hg)
10. Instrument to measure potential difference? (Voltmeter)

Day 20 (Activity)

(project or Working Model)