Page 2 - Lesson notes-Thermometer

Laboratory Thermometer:
Laboratory thermometer is used to measure different temperature in the laboratory,
food, petroleum, water, environment, etc.
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• It has a range of -10 C to 110 C.
• There is no kink present in the Laboratory thermometer.

Precautions should be taken while using Laboratory thermometer such as:
1. It should be washed before and after use.
2. It should be held in vertical position.
3. The bulb of the thermometer should dip in the substance and shouldn’t
touch the side of the container.
4. Our eye should be placed at the level of mercury while taking the
reading.
5. The reading should be taken while thermometer is still inside the liquid
or substance whose temperature is being measured.

Digital Thermometer:
A Digital thermometer has a bulb, plastic body and digital displays to record the
temperature.
• It uses thermistor in the bulb which senses the temperature.
Digital thermometer is used more nowadays as:
• It is easy to use as it has plastic body.

• It uses digital display.
• It doesn’t contain mercury which is toxic in nature.

History of the Thermometer
The thermometer is a tool used to measure temperature. Its development happened
over many years through the work of different scientists.

• Galileo Galilei (around 1593) created a device called a thermoscope. It could
show changes in temperature but didn’t have a scale to measure how hot or cold
something was.