Heat is a form of energy which exists naturally.
It easily changes into different forms of energy like light, electricity etc.
Life on this earth depends on heat energy for survival.
Man knew about heat and its precursor fire since ages and has been using it for various applications.
Heat energy unlike other forms can be felt by sense of touch.
Importance of heat
Heat and energy are quite related and know to common before advancements of science. It has great role in the human lives and also the environment. Heat energy helps to
1. Photosynthesis: In plants, light energy from sun converts to heat energy and gets trapped in the leaves to form carbohydrates.
This energy trapped again releases to generate heat energy when the carbohydrates are broken down by animal tissues.
Besides carbohydrates, heat energy is also present in fats and to some extent in proteins.
Thus energy in the from of heat is involved in food production.
2. Enzyme reactions: Enzymes are bio-catalysts which help to enhance the speed of reactions. These enzymes operate only when there is suitable temperature i.e. heat energy. At low temperature, they are inactive and the reactions do not operate.
3. Water cycle: Water cycle is great virtue to the life on earth. When the heat from sun contacts water on the earth, it evaporates. This evaporated water from the oceans form the clouds. These clouds in turn reach the land through sky and cause rains. This cycle is called as water cycle and this happens due to heat gain and cooling mechanism. When the water gets heated, it evaporates from the earth and when the clouds gets cooled (heat loss), it causes rain on the earth.
During heat temperature in summers even water on land also evaporates. The water vapor when rises above converts into clouds and cause rains when cooled. But most of the water is from oceans than from land.
4. Chemical reactions: Many chemical reactions, synthesis occur in the presence of heat energy. Due to heat energy, the electrons and atoms in the substances are set into vibration. These vibrations make it easy to form new bonds and new molecules.
5. Automobile motion: All the vehicles which run on petrol and coal operate due to generation of heat energy within. The heat energy helps the pistons to move which is conveyed into cyclic motion and thus the wheels rotate. The more the heat generated, the more the speed and strength of movement. Thus heat energy is the base for all the automotive vehicles like cars, buses, trucks etc.
6. Cooking: Cooking is a daily routine at home followed by many to make their food. Cooking helps keep the food tasty, easy to digest and also kill any microorganisms which might be harmful to health. Heat transference during cooking renders the food material and fiber more soft and pulpy.
7. Electricity generation from solar and earth geo: Electricity is generated by many means like by use of dam water, coal, nuclear energy, wind and even solar energy.
Of them solar and coal methods employ the use of heat to generate electricity.
Especially coal is used in large quantities in many countries to generate heat and there by electric current.
Even few advanced countries use geo-thermal energy (renewable) to generate electricity by safer means (non-polluting and harmful to environment).
This geo-thermal energy also is heat inside the earth.
8. Melting and molding of metals: Metals are hardest substances which are used widely for building, vehicles, hardware etc.
These metals cannot be molded with application pressure. But hey can be molded in easy way if heated.
Sometimes few metals are heated to red hot condition to mold them into proper shape.
9. Drying: Drying is done by removal of water from surfaces. This is possible by wind currents and even vacuum. But the most common method is by use of heat. Sun’s heat helps in drying clothes, soil and any other wet surfaces. Transferring heat to moist clothes set the water molecules into motion there by they easily move away into air leaving the cloth dry.
10. Sterilization: This is a process to kill any microbes in drugs and other health care material. This aims to keep the preparation sterile until use. So heat sterilization is the most common and highly effective methods of doing it. Methods like autoclave, hot air-oven, incineration use heat energy in the process of sterilization. But the process can be achieved at when the material is exposed to specific temperature and suitable duration of time.