Science (Heat) (Part 1 & Part 2) Covers the Following Topics

1. Introduction to Heat

• Seasonal clothing: Woollen clothes vs. cotton clothes.
• How we perceive hot and cold objects.

2. Hot and Cold

• How to differentiate between hot and cold objects.
• The reliability of touch for measuring temperature.

3. Measuring Temperature

• Definition of temperature as a reliable measure of hotness.
• Thermometers as tools to measure temperature.

Sub-topics:

• Clinical Thermometer
  • Structure: Narrow tube, bulb, mercury.
  • Range: 35°C to 42°C.
  • Method of use and precautions:
    • Ensure mercury is below 35°C before use.
    • Align thermometer at eye level for accurate readings.
    • Handle with care to avoid breakage.
  • Importance of the kink in the tube to hold mercury.
• Laboratory Thermometer
  • Structure and range: -10°C to 110°C.
  • Method of use:
    • Hold upright and immerse in the substance.
    • Differences from a clinical thermometer.
  • Precautions during use.
• Digital Thermometer
  • Advantages over mercury thermometers.
  • No mercury, thus safer and environmentally friendly.

4. Transfer of Heat

• Heat flow from a hotter object to a colder object.
• Three Modes of Heat Transfer:
  • Conduction:
    • Heat transfer in solids.
    • Examples: Metal rods, pans.
    • Experiment: Wax falling from a heated rod.
    • Conductors vs. insulators (examples: metals vs. wood/plastic).
  • Convection:
    • Heat transfer in liquids and gases.
    • Examples: Water heating, convection currents, sea breeze, and land breeze.
    • Experiment: Potassium permanganate in water to visualize convection.
  • Radiation:
    • Heat transfer without a medium.
    • Examples: Heat from the Sun, room heater.
    • Reflection, absorption, and transmission of radiation.
    • Dark-colored vs. light-colored surfaces.

5. Clothing and Heat

• Light-colored clothes in summer:
  • Reflect more heat, keeping the body cool.
• Dark-colored clothes in winter:
  • Absorb more heat, keeping the body warm.
• Insulating properties of woollen clothes:
  • Air trapped in fibers prevents heat loss.
• Experiment with black and white cans:
  • Understanding heat absorption and cooling.

• Application-based and reasoning questions (e.g., why thermometers shouldn’t be exposed to flames).
• Observation-based activities:
  • Measuring temperature of water, air, and humans.
  • Visualizing heat flow using experiments with rods, cans, and liquids.

1. Measuring Temperature
   • Clinical and laboratory thermometers, their differences, and usage.
   • Precautions and explanations related to thermometers.
2. Transfer of Heat
   • Detailed coverage of conduction, convection, and radiation.
   • Real-life applications like sea breeze, land breeze, heating liquids.
3. Clothing and Heat
   • Seasonal variations in clothing.
   • Experimental insights on dark vs. light surfaces.

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