How much do we really understand the difference between heat
and temperature and how it is conducted?
If we think of a cup of hot tea, when we hold onto the cup
it feels warm to the touch. Heat moves from the cup to my hand, showing us that
warm things will heat cold things by the transfer of heat or heat energy.
So to explain, the cup of tea was hot in comparison to my
hand. When I held the cup the molecules in my hand moved faster as heat energy
flowed from the mug to my hand. As a result the mug had then less heat energy
as this had been transferred to the colder item (my hand) and the molecules
within the cup begins to move slower and will continue to decrease in
temperature until the mug reaches the temperature of the room.
Two cold items can actually heat one another if you were to
rub the two together. Heat is not a calorific object but a form of energy
created by the movement of molecules in any object.
How do we measure the amount of heat energy that an object
has?
Temperature is the measure of how much heat energy an object
has.
These 3 statements are all correct
1.
The mug of tea has a higher temperature than my
hand
2.
The molecules in the mug of tea are moving
faster than the molecules in my hand
3.
Heat energy will flow in the direction from the
tea to my hand (not vice versa)
Heat can be transferred in one of 3 forms:
·
Conduction
·
Convection
·
Radiation
Heat conduction or thermal conduction is the process where
heat is transferred within a body due to the collision of neighbouring
particles. For example:
A child that has been out in the snow all day, comes into
the house and cuddles up to his mother to keep warm. This is because the heat
is transferred from the mothers’ body to his body using conduction.
Heat convection occurs when heat is transferred through a
liquid or gas by the hotter material moving into a cooler area
Boiling water is a great example of everyday convection.
Heat passes from the burner into the pot, heating the water from the bottom.
The hot water then rises and the cooler water moves down to replace it causing
a circular motion.
Radiation
The term radiation refers to energy that travels through
space or matter in the form of energetic waves or particles (called infrared
light). When radiation occurs, waves move out in all directions from the
producer of the energy.
For example when you park your car when you arrive at work
on a sunny day with no shade, the car will heat up throughout the day as the
energy from the sun is transferred to the car which is held by the vehicle and
released throughout the day, making the car extremely warm
when you enter it.
We can use all of these forms of heat transfer to warm us,
when we are cold. In a work environment you conduction would not really be used
as a good form would be to use a hot water bottle.
Convection is often used in warehouse heating and factory heating in the form of industrial warm air heaters. Warm air heating works by
pulling the cold air within the building and pushing it over the heat exchanger
where the cold air is heated and then pushed out via a fan into the building,
where the air is distributed around the building until the room reaches the
required temperature.
Radiation is often used when considering garden centre
heating using infrared radiant heaters. These work by heating the objects in
the room, rather than the air and releasing the heat energy during the day,
helping to maintain a comfortable temperature for the employees, customers and
a perfect environment for plant growth.
Heaters Wholesale specialise in providing high quality industrial heating solutions across the U.K. Including warm air heating for your factory, or radiant heaters for your garden centre.
