Chapter- Heat For Class VII students, NCERT Syllabus

1. Heat
Part-2
FOR CLASS VII
By- Vivek Singh
ABPS JAGDISHPUR

2. Key points in this power point
• Thermometer
• Types of thermometer
• Reading temperature with the help of
thermometer
• Assignment

3. • Thermometer is an instrument that is used to
measure temperature
Thermometer

4. Clinical thermometers
• The thermometer that
measures the
temperature of our body
is called clinical
thermometer.

5. Construction of clinical thermometer
• A clinical thermometer has a long narrow glass
tube. It has a bulb at one end containing
mercury.
• It has a scale called Celsius scale marked in °C
(degree Celsius).
• A clinical thermometer reads temperature from
35 °C to 42 °C.

6. The normal temperature of the human body is
37°C.
• The clinical thermometer has a small kink
(constriction) near the bulb to prevent the mercury
level from falling down.

7. Reading a clinical thermometer
• Wash the thermometer with an antiseptic solution.
Hold it firmly and give it a few jerks to bring the
level of mercury below 35 °C.
• Then place the bulb of the thermometer under your
tongue. After one minute take out the thermometer
and note the reading.
• This will be your body temperature.

8. Digital
thermometers
• Digital (electronic)
thermometers are
preferred over
conventional
mercury
thermometer.

9. Digital thermometers
• Digital thermometers are
easy to read because it
gives LCD Display of the
temperature of the
person.
• They are also mercury
free.

10. Laboratory thermometer
• A laboratory thermometer has a long narrow
glass tube.
• It has a bulb at one end containing mercury.
• It has a scale marked in °C (degree Celsius).
• The range of a laboratory thermometer is
generally from - 10 °C to 110 °C.

11. Measuring temperature with a
laboratory thermometer
• Take some tap water in a beaker.
• Dip the thermometer in the water
so that the bulb of the
thermometer does not touch the
bottom or the sides of the
beaker.

12. • Hold the thermometer vertically. The mercury
level rises.
• Wait till the level of mercury becomes steady.
• Note the level of mercury. This will be the
temperature of the water.

13. Assignment
• Make note of all slides in your notebook.
• Draw a labelled diagram of laboratory
thermometer.

14. THANK YOU