Calorimetry is the scientific study of measuring heat changes in physical and chemical processes, utilizing devices called calorimeters. Various types of calorimeters, such as bomb and direct calorimeters, are used in fields like nutrition, material science, and medicine to determine energy content, metabolism, and heat capacity. These instruments play a crucial role in applications, including nutritional labeling, metabolic studies, and industrial quality control.

1. CALORIMETER
Shiza Arshad

2. Calorimetry
• Calorimetry is the field of science that deals with the
measurement of the state of a body with respect to the
thermal aspects in order to examine its physical and
chemical changes
• The changes could be physical such as melting,
evaporation or could also be chemical such as
burning, acid-base neutralization etc.
• Calorimetry is applied extensively in the fields of
thermochemistry in calculating the enthalpy, stability,
heat capacity etc.

3. History
• In 1761 Black introduced the thought of heat of
transformation which causes the creation of the
primary ice-calorimeters
• In the year 1780, a French nobleman and chemist
Lavoisier performed an experiment in which he used
the warmth from the guinea pig’s respiration to melt
snow surrounding his apparatus almost like a candle
burning, showing that respiratory gas exchange is the
combustion

4. What is a Calorimeter?
• A calorimeter is a device used to measure the heat energy
produced or absorbed during a chemical reaction or physical
change
Composition:
1. It mainly consists of a metallic vessel made of materials
which are good conductors of electricity such as copper and
aluminium etc
2. There is also a facility for stirring the contents of the vessel.
3. This metallic vessel with a stirrer is kept in an insulating
jacket to prevent heat loss to the environment
4. There is just one opening through which a thermometer can
be inserted to measure the change in thermal properties
inside

6. Working principle
• The body at higher temperature releases heat while the
body at lower temperature absorbs heat
• The principle of calorimetry indicates the law of
conservation energy, i.e. the total heat lost by the hot
body is equal to the total heat gained by the cold body
Heat Lost = Heat Gained
• Calorimeters work by isolating the reaction or substance
inside a chamber and measuring the temperature change
that occurs due to the heat released or absorbed

7. Working principle
1. Say in a calorimeter a fixed amount of sample is burned
2. The vessel is filled with water, and the sample is burned,
leading to the heating of the water
3. Heat loss by the sample is equal to the heat gained by
the water
4. This is why it is important to insulate the calorimeter
from the environment; to improve the accuracy of the
experiment
5. This change in heat can be measured through the
thermometer
6. Through such a measurement, we can find out both the
heat capacity of water and also the energy stored inside
a sample

8. Types of Calorimeter
1. Adiabatic Calorimeters
• Adiabatic calorimeters measure the change in enthalpy of a
reaction occurring in solution. During the reaction, the no
heat exchange with the surroundings is allowed and the
atmospheric pressure remains constant
• However, The adiabatic calorimeter is actually a wrong term
because it’s not fully adiabatic. Some amount of heat is
usually lost by the sample to the sample holder. A
mathematical correction factor, referred to as the phi-factor,
are often wont to adjust the calorimetric result to account for
these heat losses

9. Types of Calorimeter
2. Bomb Calorimeters
• Since the process takes place at constant volume, the reaction
vessel must be constructed to withstand the high pressure
resulting from the combustion process, which amounts to a
confined explosion. The vessel is usually called a “bomb”, and the
technique is known as bomb calorimetry .
• To measure the heat evolved in a combustion reaction, constant
volume or bomb calorimetry is ideal. A constant volume
calorimeter is also more accurate but it is more difficult to use
since it requires a well-built reaction container that is able to
withstand large amounts of pressure changes that happen in
many chemical reactions

10. A bomb calorimeter
structure consists of the
following:
1. Steel bomb which
contains the reactants
2. Water bath in which
the bomb is
submerged
3. Thermometer
4. A motorized stirrer
5. Wire for ignition

11. Types of Calorimeter
3. Differential Scanning Calorimeter
In this differential scanning calorimeter or DSC, heat flows
into a sample which is usually contained within a small
aluminium capsule or ‘pan’. This heat flow is measured
differentially, i.e., by comparing it to the flow into an empty
reference pan

12. Types of Calorimeter
4. Reaction Calorimeter
• A calorimeter used to start a reaction inside of a sealed,
insulated container is known as a reaction calorimeter
• Heat content is calculated by integrating heat flow versus
time after measuring reaction heats. Because industrial
processes are designed to operate at consistent
temperatures, this property is used in industry to survive
the heat

13. Types of Calorimeter
5. Coffee cup calorimeter
• The cup is partially filled with a known
volume of water and a sensitive
thermometer is inserted through the
lid of the cup so that its bulb is below
the water surface. This type of
calorimeter is typically used for
solution based chemistry with little to
no volume change.

14. Uses of Calorimeter
Food and Nutrition
1. Caloric Content: Calorimeters, especially bomb
calorimeters, measure the energy content in food by
burning a sample and measuring the heat produced
2. Metabolic Studies: They help study how different foods
affect metabolism by measuring the heat produced
during metabolic processes

15. Uses of Calorimeter
3. Diet Design: Calorimeters help nutritionists design
balanced diets by accurately measuring the caloric
content of various foods
4. Food Labeling: Caloric values obtained from
calorimeters are used in labeling food products,
providing consumers with important dietary information
5. Nutrient Bioavailability: Calorimetric studies can
assess how different cooking methods affect the
bioavailability of nutrients in foods

16. Uses of Calorimeter
Materials Science
1. Heat Capacity: Calorimeters determine the specific
heat capacity of materials, which is crucial for
applications like thermal management and material
selection in engineering
2. Phase Transitions: Differential Scanning Calorimeters
(DSCs) detect phase transitions (e.g., melting,
crystallization) in materials, important for quality control
in manufacturing

17. Uses of Calorimeter
Biochemistry and Medicine
1. Drug Interactions: Calorimeters help in studying the
thermodynamics of drug interactions with biomolecules,
aiding in drug development
2. Enzyme Activity: They measure heat changes in
enzymatic reactions, providing insights into enzyme
mechanisms
3. Cell Metabolism: Calorimeters assess metabolic rates
of cells, useful in medical research and diagnostics

18. Uses of Calorimeter
Industrial Applications
1. Quality Control: In manufacturing, calorimeters ensure
the quality and consistency of products by measuring
heat changes during production processes
2. Energy Efficiency: They are used to evaluate the
energy efficiency of combustion systems, such as
engines and boilers

19. Use in Nutrition field
• A calorimeter is an essential tool in the field of nutrition
and dietetics, used to measure the amount of heat
released or absorbed by a substance, which is crucial in
determining the energy content of food. There are
different types of calorimeters used in nutrition, including
bomb calorimeters and direct/indirect calorimeters.
• Here's a detailed explanation of their use

20. Bomb Calorimeter
• Principle:
• A bomb calorimeter measures the heat of combustion of a food
sample. It provides a direct measure of the energy content by burning
the sample in a controlled environment
• Procedure:
1.Preparation: A food sample is dried and ground to ensure uniformity.
2.Combustion: The sample is placed in a crucible inside the bomb (a
strong, sealed container) with a known amount of oxygen.
3.Ignition: The sample is ignited electrically, causing it to combust
completely.
4.Heat Measurement: The heat released by the combustion raises the
temperature of the surrounding water. The temperature change is
measured and used to calculate the energy content of the sample

21. Bomb Calorimeter
• Application:
1. Nutritional Labeling: Determines the caloric content of
foods for nutritional labeling
2. Research: Used in research to study the energy
content of different food components, like fats, proteins,
and carbohydrates
3. Quality Control: Ensures consistency in the caloric
content of food products

22. Direct Calorimeter
• Principle:
• Direct calorimetry measures the heat emitted by the
human body to calculate energy expenditure. It involves a
person staying in a specially designed room where the
heat they emit is measured directly.
• Procedure:
1.Environment Control: The individual stays in a thermally
insulated room.
2.Heat Detection: Sensors detect the heat emitted by the
person over a specific period.
3.Data Analysis: The heat measurements are used to
determine the total energy expenditure of the individual.

23. Direct Calorimeter

24. Direct Calorimeter
• Application:
1. Metabolic Studies: Provides precise measurements of
total energy expenditure
2. Diet Planning: Helps in tailoring diets based on
individual energy needs
3. Clinical Research: Used in clinical settings to study
metabolism in different health conditions

25. Indirect Calorimeter
• Principle:
• Indirect calorimetry estimates energy expenditure by measuring
oxygen consumption and carbon dioxide production. This
method is based on the principle that the oxidation of nutrients in
the body requires oxygen and produces carbon dioxide.
• Procedure:
1.Respiratory Measurement: The individual breathes into a
mouthpiece or mask connected to the calorimeter.
2.Gas Analysis: The calorimeter measures the volumes of
oxygen consumed and carbon dioxide produced.
3.Energy Calculation: These measurements are used to
calculate the respiratory quotient (RQ) and energy expenditure
using specific equations.

26. Indirect Calorimeter

27. Indirect Calorimeter
• Application:
1. Basal Metabolic Rate (BMR) Measurement: Assesses
the energy expenditure at rest
2. Exercise Physiology: Determines energy expenditure
during physical activities
3. Nutritional Therapy: Helps in developing personalized
nutrition plans for weight management and clinical
nutrition

28. • Calorimeters play a crucial role in nutrition and dietetics
by providing accurate measurements of energy content in
foods and energy expenditure in humans
• Bomb calorimeters are primarily used to determine the
caloric content of foods, while direct and indirect
calorimeters are used to measure human energy
expenditure
• These tools are vital for nutritional labeling, diet planning,
metabolic research, and clinical nutrition, ensuring that
dietary recommendations and interventions are based on
precise and reliable data