HEAT-POST 5

2 MAY 2020


HEAT BLOG 5

GOOD MORNING BOYS! 

Thank you for logging in.

At the end of this lesson  you will be able to:

1.  Explain the construction of a clinical thermometer
2. Understand how to use a clinical thermometer

LET US BEGIN:

  Look at the pictures given below of a clinical or doctor's thermometer:

It is used to measure the body temperature of humans and animals.

          DIGITAL THERMOMETER

               A doctor's or clinical thermometer

CONSTRUCTION:

1. It has a glass capillary tube
2. It has a narrow kink or constriction just above the bulb.
3. The bulb and a small portion of the capillary tube are filled with mercury.
4. It is graduated from 35°C TO 42°C

THINK AND ANSWER:

Have you ever wondered why the clinical thermometer has a kink while the lab thermometer does not have one?

Answer: When the thermometer is put into a person's mouth, the mercury expands and pushes through the kink.On being taken out of the person's mouth, the KINK does not allow the mercury to go back to the bulb.This way the body temperature can be read easily and accurately.


DO YOU KNOW:
The body temperature of a normal healthy person is 37°C or 98.6 °F


HOW TO USE A CLINICAL THERMOMETER

Determine the value of one small division on the thermometer scale
for this count the number of small divisions between two big marks, eg  35° and 36°

NOW:

Value of one small division = Difference of temperature between two big divisions/ No of small divisions

= 1/ 5 = 0.2° C  [assuming there are 5 small divisions]

Thus we can measure temperatures upto  0.2° C with certainity.

     HOMEWORK

DRAW A  WELL LABELLED DIAGRAM OF CLINICAL THERMOMETER IN YOUR NOTEBOOK
Answer these questions orally-

1. Why does a clinical thermometer have a kink or constriction?
2. Why should a person not talk,yawn or move when he has a thermometer under his tongue?
3. Why is a clinical thermometer graduated only from 35°   C to 42°C?

That is all for today

See you soon