NCERT Class VII Science Solutions: Chapter 4 – Heat Part 1

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Question 1:

State similarities and differences between the laboratory thermometer and the clinical thermometer.

Answer:

  1. Similarities:

    • Working principle of both the thermometer is same.

    • Both are used to measure temperature.

    • Both have a thick walled glass tube enclosing a fine uniform bore capillary tube.

    • Mercury is used in both thermometers to measure temperature.

    • Both have Celsius and Fahrenheit markings.

  2. Differences:

  • Laboratory thermometer is used to measure temperature of different objects in factories and laboratory where as clinical thermometer is used to measure the temperature of human beings only.

  • Generally, laboratory thermometer has temperature range from −10℃ to 110℃ where as clinical thermometer has temperature range from 35℃ to 42℃.

  • Usually laboratory thermometer does not have any constriction where as clinical thermometer has the small constriction near the mercury bulb.

  • Laboratory thermometer has to be kept upright while taking the reading where as clinical thermometer can be tilted while taking reading.

As showing in images is a clinical thermometer and laboratory thermometer

Clinical Thermometer and Laboratory Thermometer

As showing in images is a clinical thermometer and laboratory thermometer

Question 2:

Give two examples each of conductors and insulators of heat.

Answer:

Conductors: Copper, aluminum and iron.

Insulators: Wood, water and air.

As showing in images is a conductors and insulator

Conductors and Insulator

As showing in images is a conductors and insulator

Question 3:

Fill in the blanks:

  1. The hotness of an object is determined by its __________.

  2. Temperature of boiling water cannot be measured by a _____________ thermometer.

  3. Temperature is measured in degree ______________.

  4. No medium is required for transfer of heat by the process of __________.

  5. A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of ______________.

  6. Clothes of ______________ colours absorb heat better than clothes of light colours.

Answer:

  1. The hotness of an object is determined by its temperature.

  2. Temperature of boiling water cannot be measured by a clinical thermometer.

  3. Temperature is measured in degree Celsius.

  4. No medium is required for transfer of heat by the process of radiation.

  5. A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of conduction.

  6. Clothes of dark colours absorb heat better than clothes of light colours.