Energy is the driving force for the universe. We think of energy as the ability of a system to do work. Work is a force applied to an object over a certain distance, such as pulling or pushing a book across the surface of your desk. Your muscles do work when they enable body movement.
“Energy makes things go, makes things run, makes things move, makes things fun!”
~ Bill Nye
Forms of Energy
Energy can be classified as either potential (stored energy) or kinetic (energy of motion) yet it can take many different forms. One form of energy can be changed to another form. The laws of thermodynamics govern how and why energy is transferred. Before the different types of energy resources and their uses are discussed, it is important to understand a little about the basic laws of energy.
By definition, work is an energy requiring process. So, how do you describe energy? Energy is not a substance that can be held, seen, or felt as a separate entity. We cannot create new energy that is not already present in the universe. We can only take different types of materials in which energy is stored, change their state, and harness the energy in order to use it to do work for us. If the released energy is not harnessed, it will generally change to heat energy and “wasted”.
The first law of thermodynamics, also called conservation of energy, states that the total amount of energy in the universe is constant. This means that all of the energy has to end up somewhere, either in the original form or in a different from. We can use this knowledge to determine the amount of energy in a system, the amount “lost as waste” heat, and the efficiency of the system.
After discussing these concepts briefly in class, we dived into a lab activity to explore in more depth how we can convert the potential chemical energy inside a battery to kinetic energy by creating a very simple motor.
Simple Motors Lab
Materials (per child):
- 1 D-cell battery
- 1 meter of 20-22 gauge enameled copper wire
- 1 rectangular ceramic magnet
- 2 large paper clips
- masking tape
- Hold the wire so that approximately 5cm extends beyond the tip of your fingers.
- Wrap the remaining wire around two fingers until about the same length of wire extends below your fingers.
- Wrap one of the “tails” around the coil to tie it together at the narrow end of the oval.
- Do the same with the other “tail” so that the coil is held together. A well-made coil can rest on its “tails” between two outstretched fingers and spin easily.
- Sand all the insulation off the wire on one of the “tails” (it will be a bright copper color where the insulation has been removed). On the other “tail” only sand the insulation off about half way around the wire. On both “tails”, make sure you sand right up to the coil.
- Take the safety pins onto the end of the battery and stick the magnet to the battery. Make sure the holes in the safety pin line up.
- Rest the coil in the loop of the two safety pins.
- Give the coil and gentle spin and your motor should start turning on its own.
- Make sure the coil is well balanced so that it spins freely when resting on the pins.
- Make sure that your sanding job was good. All sanded areas should show bright copper.
- Hold the safety pins to the battery with your fingers to make sure they are contacting the battery at the terminal ends.
After you get the motor to work, try doing either of the following:
- Make the motor go faster.
- Make the motor go in reverse.
As you work on your motor, record what you want to do in the form of a question. After each question, note what you did and what you observed. For example, you may want to ask a question like: How will the shape of the coil affect the speed of the motor?
Science Logic: Electricity & Magnetism
This lesson will be included in the Science Logic: Electricity & Magnetism unit that I hope to release by April 2014. In addition to the simple motor illustrated here, instructions for a simple speaker and simple generator will also be provided.