Explain How A Thermometer Works


Explain How A Thermometer Works?

A thermometer has a glass tube sealed at both ends and is partly filled with a liquid like mercury or alcohol. As the temperature around the thermometer’s bulb heats up the liquid rises in the glass tube. … When it is hot the liquid inside the thermometer will expand and rise in the tube.

How does a thermometer work?

How does a thermometer tell the temperature? A thermometer measures temperature through a glass tube sealed with mercury that expands or contracts as the temperature rises or falls. … As temperatures rise the mercury-filled bulb expands into the capillary tube. Its rate of expansion is calibrated on the glass scale.

What is the best explanation for how a thermometer works?

The way a thermometer works is an example of heating and cooling a liquid. When heated the molecules of the liquid in the thermometer move faster causing them to get a little further apart. This results in movement up the thermometer.

How does a thermometer work quizlet?

A thermometer works because the liquid in it (alcohol or mercury) expands or contracts by a certain amount as the temperature changes. … Some thermometers work by using a material whose electrical properties change as the temperature changes.

What is thermometer short answer?

A thermometer is a tool that measures temperature — how hot or cold something is. Thermometers are used to see if you have a fever or tell you how cold it is outside. Made up of thermo (heat) and meter (measuring device) the meaning of the word thermometer is pretty straightforward.

What is the function of a laboratory thermometer?

Laboratory thermometers are devices used to measure temperature. There are many types of lab thermometers such as differential mechanical logging etc. Laboratory thermometers are progressively providing digital reading displays and are input-capable to computer and software programs for logging purposes.

What do thermometers actually measure?

A thermometer is an instrument that measures temperature. It can measure the temperature of a solid such as food a liquid such as water or a gas such as air. The three most common units of measurement for temperature are Celsius Fahrenheit and kelvin. The Celsius scale is part of the metric system.

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Does a thermometer measure heat or temperature explain?

Despite its name however a thermometer does not actually record heat but rather temperature. … Temperature is a measure of the average kinetic energy of the molecules within a substance.

Why mercury is used in thermometer?

Mercury is the only one in liquid state at room temperature. It’s used in thermometers because it has high coefficient of expansion. Hence the slightest change in temperature is notable when it’s used in a thermometer. It also has a high boiling point which makes it very suitable to measure higher temperatures.

What is used in thermometers and barometers?

Answer: As the only metal that is liquid at room temperature mercury expands and contracts evenly with temperature and pressure changes. These characteristics have made mercury useful in devices used for measuring temperature and pressure including the following: Barometers measure atmospheric pressure.

Why is alcohol used in thermometers?

Alcohol thermometers are used rather than mercury thermometers in very cold regions because alcohol has a lower freezing point than mercury. … If it freezes it won’t move in the tube so a liquid must be used that has a freezing point that’s lower than the temperature it’s measuring.

Why do thermometers use a liquid instead of a solid or gas?

Liquids are used in thermometers because they expand and contract with temperature changes and they take on the shape of a container without filling it. Solids do not work in thermometers because they do not take on the shape of the container.

How do we define temperature?

Temperature is the measure of hotness or coldness expressed in terms of any of several scales including Fahrenheit and Celsius. Temperature indicates the direction in which heat energy will spontaneously flow—i.e. from a hotter body (one at a higher temperature) to a colder body (one at a lower temperature).

What is the basic principle of a thermometer?

These liquid thermometers are based on the principal of thermal expansion. When a substance gets hotter it expands to a greater volume. Nearly all substances exhibit this behavior of thermal expansion. It is the basis of the design and operation of thermometers.

What are the three uses of thermometer?

To measure the outdoor temperature. – To measure body temperature during a physical exam at the doctors. – To measure body temperature when someone is ill to determine if he/she has a fever. – To measure the temperature of an oven.

Why is the thermometer important?

Thermometers are used to measure the temperature and this is a very important part of weather forecasting. Many thermometers come in a glass tube that contains a liquid usually mercury or alcohol. … Knowing the air temperature is very important. It is an important part of weather forecasting.

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What is the function of pipette?

About Pipettes. A pipette is a laboratory instrument used to measure out or transfer small quantities of liquid in volumes of milliliters (mL) microliters (μL).

What are the 2 important things that he does upon using thermometer?

A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a mercury-in-glass thermometer or the pyrometric sensor in an infrared thermometer) in which some change occurs with a change in temperature and (2) some means of converting this change into a numerical value (e.g. the visible scale …

How are thermometers made?

A thermometer is usually made up of a small hollow glass tube. At the bottom of the tube is a bulb which holds a liquid such as alcohol or mercury. When there is an increase in heat the liquid inside the bulb expands pushing up into the tube. A decrease in heat lets the liquid contract moving down the tube.

How do thermometers work without mercury?

Spirit thermometers use a non-toxic alcohol instead of mercury to register the temperature. … Digital thermometers contain a device called a thermoresistor. The thermoresistor has an electrical current running through it and the resistance or how freely the current can flow changes with temperature.

What are the 3 scales of temperature?

Temperature Scales. There are three temperature scales in use today Fahrenheit Celsius and Kelvin. Fahrenheit temperature scale is a scale based on 32 for the freezing point of water and 212 for the boiling point of water the interval between the two being divided into 180 parts.

What are the 4 types of temperature?

The Four Types of Temperature Scales
  • Fahrenheit Scale. ••• The Fahrenheit scale of temperature is the common form of temperature measurement used in the United States and some parts of the Caribbean. …
  • Celsius Scale. ••• …
  • Kelvin Scale. ••• …
  • Rankine Scale. •••

What are the 5 temperature scales?

Celsius Fahrenheit Kelvin Réaumur and Rankine.

What is the red liquid in a thermometer?


Mercury is a silver-white to gray substance. If your thermometer is filled with a red liquid your thermometer contains red dyed alcohol or mineral spirits and not mercury.

What do F and C means in thermometer?

There are two scales used for taking temperature: Fahrenheit (F) and Centigrade (C).

Which liquid is used in laboratory thermometer?

Liquid-in-glass thermometers are made of sealed glass and contain a fluid usually mercury or red alcohol whose volume changes relative to its temperature. The liquid expands as the temperature rises rising in the tube and indicating the temperature.

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What is altimeter and barometer?

While a barometer and an altimeter both measure pressure an altimeter is further developed to compare barometric (atmospheric pressure) levels and represent the changes as a change in altitude.

What is barometer with diagram?

Simple barometer

An inverted glass tube is standing in the bath of mercury and air pressure is exerted on the surface of mercury. The pressure at the top of the mercury column is zero as there is a vacuum there.

How do you read a barometer?

Reading a barometer is simple if you know what different atmospheric pressure values indicate.

If the reading is under 29.80 inHg (100914.4 Pa or 1009.144 mb):
  1. Rising or steady pressure indicates clearing and cooler weather.
  2. Slowly falling pressure indicates rain.
  3. Rapidly falling pressure indicates a storm is coming.

What is the blue liquid in a thermometer?

The science and development of non-mercury thermometers have made great improvements over the past few years. The blue spirit thermometers listed contain non-toxic isoamyl benzoate and dye. These thermometers can be stored horizontally their separation rate is equal to or better than mercury thermometers.

Why is the wall of the thermometer bulb thin?

The bulb of the thermometer needs to be thin because the glass while a good material for most of the thermometer design is a poor conductor of heat. The mercury inside is metal and an excellent heat conductor but the glass is an insulator.

Why water Cannot be used as a thermometric liquid?

A. higher freezing point and low boiling point than other thermometric liquids. Therefore water is having a high boiling point. …

Why is mercury used in thermometer Class 7?

We use mercury in thermometers because most metals are good conductor of heat and mercury is the only metal in liquid state. It expands as per temperature and has high coefficient of expansion.

Why solids are not used in thermometer?

In thermometer mercury is used because it is a metal having property of low melting point and it melts at room temperature also it expands in the presence of heat. If we use solid and gases they do not expand much may gas expand but they have not fixed volume so they move in whole thermometer which is not practical.

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