CONCEPT OF TEMPERATURE

INTRODUCTION

After the long ride, one might feel hot when you touch the motorway of the vehicle. If you swim in the pool with water below zero degrees, you feel cold. There is no science behind it.But if the animals like polar bears living in the poles touch the ice cubes, it may feel hot. Heat, cold, temperature are all interrelated terms. Hot and cold are different terms but represent the same concepts about the transfer of energy.What is temperature, and how does the concept of temperature work? Let us learn more.

HEAT AND TEMPERATURE

Heat and temperature are closely related, but there is a slight difference between them. The concept of temperature deals with the molecular K.E (kinetic energy), whereas heat deals with thermal energy.For example – Temperature tells how hot or cold is the object isHeat deals with the transfer of energy to the object (ex- stove heat pans)The transfer of thermal energy between two bodies is defined as heat, and it is expressed in Joules.Heat tells us how the energy moves or flows between two systems.

HEAT

The energy present in the form of heat is called heat energy. In a hot system, more heat energy is usually present, and in a cold system, there is less heat energy.Compared to humans, polar bears and icebergs have more heat energy.The particles like atoms and molecules present in the objects collide with each other and produce the kinetic energy of the particles. They are the ones that help to understand the concepts in better ways.

For example- If you put the vessel full of water over the stove, the water starts to boil. The water will start boiling faster if the heat is increased. It is due to the collision of molecules present in the water. After 100 degrees celsius, the water turns into a gas, becomes a vapour, and starts to evaporate.

MEASURING HEAT

• The heat will be transferred from one system to another and is measured in joules
• Other than joules, ‘calories’ is the unit that can be used to measure the heat
• Through a calorimeter, one can measure the heat of the object

Here are some of the factors on which heat depends:

• speed of the particle
• size of the particle
• number of the particles

Temperature is independent of all the factors mentioned above.

TRANSMISSION OF HEAT

There are three ways involved in the transmission of heat :

1. Conduction
2. Convection
3. Radiation

CONDUCTION

1. If a solid body is heated, the atoms and molecules present in the solid body begin to move and start colliding hence after. They will gain kinetic energy, and the molecules present in the solid mass begin to vibrate.
2. Due to the transfer of heat from one particle to another, the particles begin to vibrate. This process is called conduction.
3. If the particles present in the body are closely attached, more force is required for the transfer of energy from one particle to another. This type of body is called a good conductor.

CONVECTION

Here in this process, heat flows in liquids and gasses.For example, if you put the vessel of broth in the oven and heat it, the lower part of the broth that is closer to the stove warms up faster than the upper part of the broth. After some time, the lower part of the broth comes up, and the upper part of the broth goes down. You can see the circulation of heat between the broth in the vessels, but the heat conveyor can’t be seen with naked eyes. The circulation of the upper side and lower side of the broth where the whole vessels get heated up is called convection.

RADIATION

• Here in this process, we obtain heat energy from the sun
• There is no medium required to transfer heat energy in this process. It can travel in space
• Just like radio waves and microwaves, it can be transferred in the form of electromagnetic waves

CONCEPT OF TEMPERATURE

• Whether the object is hot or cold, it can be determined with the help of temperature
• Temperature is defined as the energy possessed by the particle that is directly proportional to the kinetic energy possessed by the particles
• In the concept of temperature, the temperature can be measured in terms of Kelvin, Fahrenheit, and Celsius
• Temperature is an independent condition that does not depend on many factors such as the number, size, and quantity of the particles
•  Analog thermometers and digital thermometers are the two types of thermometers used to measure the system’s temperature

For example, let us compare a bucket of water and a glass of water. The water present in the bucket and the glass can be at the same temperature. But the number of particles present in the bucket is more compared to the number of particles present in one glass of water. So the water present in the bucket has more thermal energy in it. Therefore, the water bucket has more heat even though both the bucket and the glass of water have the same temperature.

MEASURING TEMPERATURE

There are different ways of measuring the temperature of the body. It can be measured in terms of Kelvin, Fahrenheit, and celsius. For example, Americans use Fahrenheit, and Canadians use celsius.

THE CELSIUS SCALE (0°C)

• The temperature ranges from 0°C of ice to the boiling point of water at 100°C
• The major disadvantage of this scale is that no negative values can be measured that are below 0°C

THE KELVIN SCALE

• It has zero on the point scale. All types of pressures and volumes of the gas can be measured with the help of the Kelvin scale
• You can convert degree Celsius to degree Kelvin by adding 273 to the Celsius degree (T_k= T_c + 273)

TEMPERATURE CONVERSION FORMULA

• For conversion of Fahrenheit to celsius °C = (°F – 32) × 5/9
• For conversion of celsius to Fahrenheit use (°C × 9/5) + 32 = °F
• For conversion of celsius to kelvin T_k= T_c + 273
• For conversion of kelvin to celsius,  T_c= T_k – 273

CAN HEAT AND TEMPERATURE BE THE SAME?

• Whether the object is hot or cold, it can be determined with the help of temperature

For example, ice cubes and icebergs have the same temperature, but their heat energy may differ. It is because the icebergs are larger, so more particles are present in the body. Hence they possess more energy compared to ice cubes. The icebergs have more heat energy since they have millions of particles than that of a cup of tea and a hot molten steel rod.