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Question
Describe a clinical thermometer. How does it differ from the thermometer used in laboratory?
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Solution
A clinical thermometer has a narrow stem and a long bulb filled with mercury (or alcohol). There is a small constriction in the stem above the bulb. When the bulb of the thermometer is held in the armpit or the mouth of a patient, the mercury (or alcohol) in the bulb rises in the stem.
When it is taken out of the patient’s body, the small constriction does not allow the mercury (or alcohol) from the stem to retreat into the bulb. Thus, this arrangement enables us to read the temperature of the patient’s body at ease after the removal of the thermometer from his body
The figure shows a clinical thermometer. It has a slight bend or kink in the stem just above the bulb, this kink is called the constriction which prevents the mercury from falling back all by itself. As the body temperature of a healthy person is 37°C, clinical thermometers are designed to measure temperatures between 35°C and 42°C.
Clinical thermometer
RELATED QUESTIONS
The body temperature of a healthy man is;
Mercury is often used in laboratory thermometers because it ______.
Match the following
| i. | Clinical thermometer | A form of energy |
| ii. | Normal temperature of human body | 100°C |
| iii. | Heat | 37°C |
| iv. | Boiling point of water | 0°C |
| v. | Melting point of water | Kink |
Draw the diagram of a clinical thermometer and label its parts.
All clinical thermometers have a ______ that prevents mercury from flowing back into the bulb.
Before use, the mercury level in clinical thermometer should be below ______.
Fahrenheit scale is more sensitive that the Celsius scale.
Name the principle which is used in a thermometer.
Mention any two precautions to be followed while using a clinical thermometer.
How does a clinical thermometer differ from the thermometer used in the laboratory?
