Shop Windows to the Universe

The Spring 2011 issue of The Earth Scientist is focused on modernizing seismology education. Thanks to IRIS, you can download this issue for free as a pdf. Print copies are available in our online store.
Water flowing in pipes makes a pretty good analogy for electricity flowing in a circuit. A battery is like a pump, while electrons flowing through wires are analogous to water flowing through pipes.
Click on image for full size

Electric Circuits: a Water-in-Pipes Analogy

Electric current is the continuous flow of electrons through a conducting material (like a copper wire). Electrons are invisible so to understand the basics of how circuits work, it helps to examine a mechanical system that behaves in many ways similar to the electric circuit.

This mechanical system consists of a pump pushing water through a closed pipe. If we imagine that the electrical current is similar to the water flowing through the pipe, then the following parts of the two systems are related:

 
  • The pipe is the counterpart of the wire in the electric circuit
  • The pump is the mechanical counterpart of the battery.
  • The pressure generated by the pump, that drives the water through the pipe, is like the voltage generated by the battery to drive the electrons through the circuit.
  • The seashells plug up the pipe and constrict the flow of the water creating a pressure difference from one end to the other. In a similar manner the resistance in the electric circuit resists the flow of electricity and creates a voltage drop from one end to the other. Energy is lost across the resistor and shows up as heat.

The power in the circuit is given by the product of the voltage and the current. The same power can be carried by a high voltage and a low current as is carried by a low voltage and a high current. The higher the current flow however, the more energy is lost through heating the wires when traversing the circuit. That's why high voltage and low current is used when transporting electrical energy along power lines.

Last modified February 17, 2009 by Randy Russell.

Shop Windows to the Universe Science Store!

Our online store includes books on science education, ranging from evolution, classroom research, and the need for science and math literacy!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Direct Current (DC) & Alternating Current (AC) Electricity

There are two types of electrical currents that can flow through wires: direct current (DC) and alternating current (AC). Direct current (DC) flows in the same direction all the time through an electric...more

How Space Weather Can Damage Transformers

The transformer is not a power source. It functions like a lever to convert a small voltage pushing a large electric current into a large voltage pushing a small electric current or vice versa. The power...more

The Effects of Radiation on Electronics

Radiation can damage electronic circuits and it can cause electronics to malfunction. Radiation can degrade the semiconductor materials used in electronics, reducing the useful lifetime of the electronics....more

Problems Restoring Electrical Power After a Blackout

Power grids were not designed to fail completely and be started-up all at once. The basic problem is that it takes energy to produce energy. Hydroelectric, steam and nuclear power plants all require energy...more

The Magnetic Field

The force of magnetism causes material to point along the direction the magnetic force points. This property implies that the force of magnetism has a direction. As shown in the diagram to the left, the...more

Planetary Magnets

The Earth is a good example of a planetary dipole, where the lines of force point in a direction out of the South (magnetic) Pole and into the North (magnetic) Pole. Planets can also show evidence of quadrupoles...more

Eccentricity of an Orbit

Most objects in orbits move along an elliptical path. An ellipse is a shape that can be thought of as a "stretched out" circle or an oval. An ellipse can be very long and thin, or it can be quite...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF