trace how thermal energy can
transfer from one object to another by conduction.
What
is thermal energy?
Inside every object or substance are tiny particles
(molecules). These particles are always moving. In cooler substances,
the particles are moving slowly. In hotter substances, the particles
move much faster.
The particles inside
an ice cube are moving very slowly.
The
particles in boiling water are moving very fast.
Thermal energyis the energy
created by moving particles inside a substance.
more
movement of particles = more thermal energy
therefore...
A pot
of boiling water has more thermal energy than an ice cube.
Remember the pot of boiling water? How
did the water get so hot? First, it's important to know that
thermal energy is transferred when two objects touch each other.
Here's how it worked for the water:
1. The metal pot touched the hot stove.
2. The thermal energy from the stove
transferred to the pot making its particles move faster.
3. The thermal energy from the pot transferred
to the water making its particles move faster.
4. Eventually, the particles in the water
moved so fast that the water began to boil.
This process illustrates conduction.
Conduction takes place when thermal
energy is transferred from one object to another when they
are touching.
Objects that allow
thermal energy to pass through them easily are called conductors.
What
is heat?
Thermal energy always moves from hotter
objects to cooler objects. Looking at the diagram below you
should notice that the object in the middle is at a higher temperature
than the two objects on the side. The arrows show the direction thermal
energy would flow if these objects were placed in contact with each
other.
The orange and yellow arrows in
the diagram represent thermal energy. So when one object conducts
thermal energy to another, we call that heat. Heat is not
the energy itself, but the transfer. Thermal energy is transferred
in three ways:
