This document discusses thermometers and viscometers. It provides information on: 1) Thermometers measure temperature using the principle of mercury expanding when heated and contracting when cooled, causing the liquid column length to change. 2) Types of thermometers include mercury, alcohol, bimetal, infrared, and digital thermometers. 3) Viscometers measure viscosity using the principle that viscous liquids resist flow, exhibiting decreasing pressure.

1. RANI LAKSHMI BAI CENTRAL AGRICULTURAL UNIVERSITY,
JHANSI,UP
TOPIC: Thermometer and viscometer
COURSE: Basic concept in laboratory techniques PGS 504 1[0+1]
SUBMITTED TO,
Dr.Abhishek kumar,
Dept. Biotechnology,
RLBCAU, Jhansi.

2. Thermometer
• Thermometer is a device that measures temperature or
temperature gradient.
• Priniciple: The measurement of temperature is performed by
the thermometer by using mercury, which expands when
heated and contracts in response to a fall in temperature.
• This causes the length of liquid column to longer or shorter
depending on the temperature.

3. Parts of thermometer
Mercury thermometer
Alcohol thermometer

4. Types of Thermometer
• Monometric thermometer Gas thermometer

5. Bimetal thermometer Infrared thermometer

6. Alcohol thermometer Digital thermometer

7. Mercury thermometer Minimum maximum thermometer

8. Applications
• Laboratory thermometers are used in research and scientific
applications such as monitoring experiments.
• Maintaining and calibrating other laboratory instruments.
• To determine the hotness of the body.
• To determine boiling points.

9. Formulas
• °𝐹=
9
5
× ℃ + 32
• ℃ =
5( ℉−32)
9
• K=273+℃

10. Precautions
• The thermometer should be kept upright not tilted.
• Bulb should be surrounded from all sides by the substance of
which temperature is to be measured.
• Bulb should not touch the container.

11. Viscometer
• Viscometer is an instrument used to measure the viscosity
which vary with flow conditions.
• Principle: The viscometer is based on the fundamental
priniciple that viscous liquid resists flow, exhibiting a
decreasing pressure.

12. Formulae
• V=
∏∆𝑃𝑟4 𝑡
8ŋ𝐿
v=volume of the liquid.
r=radius of vessel.
t=time.
ŋ=coefficient of viscosity
∆P=Change in pressure
L=vessel length

13. PARTS OF VISCOMETER

14. Advantages
• Measures precise viscosities for many diverse
fluids.
• It is used in compressors and engines.
• It also used in refineries.
• It is used to solve the simplest problems of fluid flow.
• To determine the molecular structure of the substances.
• We can use a wide variety of capillary tubes on the same
viscometer.

15. Disadvantages
• No single tube is suitable for all viscosities.
• Basic models can only used for translucent fluids.
• Difficulty to clean the capillary tubes.
• Frictional drags increase in temperature.

16. SUBMITTED BY,
HARISH J,
AG/PG/0020/19,
JUNIOR M.Sc(PLANT PATHOLOGY).