This chapter explains that temperature tells us how hot or cold an object is. It is measured in degrees Celsius (°C) using a thermometer. The chapter describes two main types of thermometers: the clinical thermometer, used to measure human body temperature (normal temperature 37°C or 98.6°F), and the laboratory thermometer, used in experiments to measure a wider range of temperatures. It highlights important precautions while using a thermometer, such as holding it upright, reading it at eye level, and not touching the bulb, to avoid parallax error. The chapter also explains that heat always flows from a hotter body to a colder body until both reach the same temperature. It clearly distinguishes between heat, which is a form of energy, and temperature, which is the degree of hotness or coldness. Finally, it explains that thermometers work on the principle of expansion of mercury or alcohol when heated.
Key Points
Temperature tells us how hot or cold an object is.
It is measured in degrees Celsius (°C) using a thermometer.
Clinical thermometer: measures human body temperature (range 35°C – 42°C). Normal body temperature = 37°C (98.6°F).
Laboratory thermometer: used in experiments (range –10°C to 110°C).
Precautions while using a thermometer:
– Hold upright, not tilted.
– Read at eye level.
– Do not touch bulb while measuring.
– Shake clinical thermometer before use to bring mercury below 35°C.Heat flows from a hotter body to a colder body until both reach the same temperature.
Difference between heat and temperature:
– Heat = form of energy.
– Temperature = degree of hotness or coldness.Thermometers work on the expansion of mercury or alcohol with heat.
👉 👉Temperature helps us understand and compare hotness or coldness. Measuring it correctly ensures safety, health, and accuracy in science.