Heat energy Lesson three
Jan 04, 2016
Heat energyLesson three
We get heat through many ways such as-:
1.The sun.2.friction.
Friction:- It is a method to generate heat as a
principle of converting the kinetic energy (mechanical energy) into heat energy.
The production of heat:- Mechanical energy change into
heat energy by friction. Kinetic energy change to heat
energy be friction.
The heat energy-:It is a form of energy which is
transferred from the object of higher temperature to that
of lower one. The temperature:- It is the heat condition which state
the direction of heat energy whether from or to the object when it comes in cannot with another.
Heat transfer by conduction:-
It is the transfer of heat through solids from the part of higher temperature to the part of lower temperature.
By convection:-
It is transfer of heat in gases and liquid ,where hot molecules which have less density rise up words
,while colder molecules which have more density fall down.
By radiation:-
It is the transfer of heat from hot object to another without any need for material medium through which heat transfers.
Give reason:-
The electric heater is placed at the bottom of the room.
When air around the heater is heated , its density decreases so , it rise up to the room , while the colder air falls down to be heated again and so on.
The heat of the sun does not reach to ground by convection or conduction.
it is not transferred by convection ,because there is vacuum between the sun and the air and it is not transferred by conduction because the air is bad conductor of heat.
The technological application:-
Some of these application work by:-
The solar energy(permanent resource of energy).
The petro (non-permanent resource of energy).
the electricity (a renewable resource of energy).
The effect on the environment.
The kind of energy resource.
The resource of energy depending on it.
The device
Non-polluted
renewable electricity Electric heater:Water heater:
Non-polluted
permanent The sun Solar heater:
Non-polluted
renewable electricity Electric stove:
polluted Non-renewable
Petroleum derivation
Gas or petrol stove:
polluted Non-renewable
Natural gas
Gas oven:
polluted Non -renewable
coal Coal fire