December 7, 2017
Physics 2 Project
Convection, and Radiation
There are three modes of heat transfer which are conduction, convection,
and radiation. Liquids and gases are poor conductors of heat. Convection is a
process where the transfer of heat occurs due to the movement of liquids or
gases, due to variations of temperature. There are different types of
convection such as natural, atmospheric, and forced convection. Natural
convection happens because of most liquids and gases tend to expand when
heated, which means that they become less dense and to rise ad a result of the
increased buoyancy. Natural convection basically means that it is caused by a
change in the density from hot and cold areas of the fluid.
natural convection would be boiling water. There has to be a sort of heat
source that heats up the pot, which heats up the water up from bottom to top.
This means that as the water heats up, it is moving to the top of the pot and
the cold water is moving to the bottom of the pot for heat. When the water gets
hot it begins to steam which is the heat being moved into the air. Melting ice
is a natural convection because the warmer temperature surrounds the ice, which
turns the water from a solid to a liquid. A not so common example of natural
convection would be a hot air balloon. The balloon has a heater that heats the
air and the balloon is trapping the heated air. The trapped heated air is what
causes the balloon to rise into the sky. To lower their selves, they simply
release the hot air and cold air replaces it.
Forced convection is the process where the transfer of
liquid and gases occur from ways other than the change in temperature. The most
common examples for forced convection would be moving water through a pump or
air with a fan. The most
common example of forced convection is the convection oven. This particular
type of oven is used to cook food at a fast rate. It is able to cook the food
fast because it moves the heat within the oven with the use of fans. Convection
ovens use fans to circulate heat so that whatever you’re cooking cooks faster
and more evenly. There everyday examples that we do not think about such as
heating and air conditioning, car radiator, because it uses radiator fluid, and
even blood circulating through a body.
plays a large role with the weather and earth. It plays a role in the weather
moves the heat and other atmospheric properties through movement in the air. AIDNSN “The sun heats the earth’s surface, then, when
cooler air comes into contact with it, the air warms and rises, creating an
upward current in the atmosphere. That current can result in wind, clouds, or
other weather.” The convection within earth’s surface cause it to slowly shift.
In the case of the ocean it makes the currents.
is the movement of energy represented by heat or electricity from one to
another by direct contact with each other. Conduction can occur in liquids and
gases but is most effective seeing as solids are packed close together.
two types of conduction: conduction of heat and energy. Conduction of heat
takes place because the temperature of the particle is increased. The conducting
is occurring through a series of vibrations and movements, which gives off the
heat to other particles in contact with it. An example of conduction of heat
would be touching something hot with your hand. An everyday
conduction of heat would be when we iron clothes. We transfer the heat of the
hot iron to the clothing by pressing (the contact) the iron to the clothing. Other
examples of heat conduction would be the hood of a vehicle being hot because the
engine has been on and releasing heat. Putting a heating pad on your body is a
conduction of heat because the heating pad is transferring the heat to the
body. Heat is conducted from a fire to a coat hanger when roasting marshmallows.
If you hold chocolate or an ice cube in our hand, it will melt because of the
conduction of heat from your body/hand to the chocolate and ice cube. Walking across
a hot surface, like sand or asphalt, conduct the heat to your feet, if you do
not have any shoes on. Cooking on a stove is also a conduction of heat. The stove
is in contact with the pan, which is in contact with the food. Your hands could
also be in contact with the hot pan, this would cause you to burn your hand
because the heat is conducted to the body. Having a light bulb on for an
extended period of time, which will cause the bulb to get warm. If you come
into contact with the hot bulb it burns you as well. When a person is cold,
another person can hold you (contact) which will warm you up. This is also the
case with a blanket or articles of clothing.
Conduction of energy is occurring because
of the transfer of electrically charged particles through a connector. The electrically
charged particles generally move through an electric current. A conduction of energy
that we use every day would be electricity in our homes. The electrical current
moves though conducting wires to the outlets and light switches. This is what
allows us to watch tv, charge phones, use computers lamps, hair straightener
and blow dryer. A common problem with electrical conduction is having live
wires and not being aware. A person that has contact with a live wire will electrocute
them because the human body is made up predominantly of water, which is a
conductor of electricity. Other good
conductors of energy would be aluminum, brass, bronze, copper, gold, graphite,
iron, mercury, steel, and silver.