and Snow Tubing
I have never been too keen on winter sports,
because it is usually just way too cold, but I decided I’d brave the
weather to give snow tubing a try at Winterplace Ski Resort, Beckley.
I grabbed my snow tube, and hopped a lift on the
Super Carpet, which is like a conveyor belt at the grocery store, except
it carried me to the top of a large snow covered hill. I picked my lane,
sat in my tube, and . . . nothing happened. I gave myself a small push
off, and I was going down the hill like a shot. I had no idea I would be
going that fast. I thought, “What a rush!” and back I went into line to
wait my turn again.
I thought the trip provided the perfect opportunity
to explain the physics concept of potential and kinetic energy. Energy
can be classified into two main forms: potential and kinetic. It can be
transferred from potential to kinetic and between objects.
An object can store energy as a result of its
position. When I was sitting in the tube at the top of the hill, I had
the potential to go downhill. This stored energy of position is called
potential energy. Similarly, a drawn bow is able to store energy as a
result of its position. When the bow is not drawn, there is no stored
energy, but when the bow is drawn back it possesses potential energy.
These examples illustrate the two forms of
potential energy: gravitational potential and elastic potential.
Gravitational potential energy is stored as the result of an object’s
vertical position or height, such as me in the tube, and is dependent on
two things--my mass and the height on the hill. There is a direct
relation between gravitational potential energy and the mass of an
object. More massive objects have greater gravitational potential
energy. There is also a direct relation between gravitational potential
energy and the height of an object. The higher that an object is
elevated, the greater the gravitational potential energy.
Elastic potential energy is stored in elastic
materials as a result of stretching and compressing. It can be stored in
objects like rubber bands, springs, and bungee cords. The amount of
elastic potential energy stored in an object is related to the amount of
stretch of the device. The more stretch the object has, the more stored
energy the object possesses.
The next type of energy I experienced was kinetic
energy-- the energy of motion. An object that has motion, whether it is
vertical or horizontal motion, has kinetic energy. When I raced down the
hill, I was experiencing kinetic energy, which can be vibrational,
rotational, or translational.
The movement of an object from one place to another
is translational kinetic energy. A reporter riding a snow tube downhill
is translational kinetic energy. An object can also have vibrational
kinetic energy--motion possessed by an object that is vibrating about a
fixed position. A mass attached to a spring has vibrational kinetic
energy. An object can also have rotational kinetic energy, associated
with an object that is rotating about an imaginary axis of rotation. A
spinning top isn’t moving through space and isn’t vibrating about a
fixed position, but there is still kinetic energy associated with its
motion about an axis of rotation.
You can illustrate these concepts at home, such as
shooting a rubber band or rolling a ball downhill. These are just a few
of the examples of the potential and kinetic energy around you.