Related Links

  • Science Fair Project Guide

Project Summary

Difficulty  6 
Time required Average (about one week)

Donate to Science Buddies

Sponsor

Sponsored by generous support from AMD

* Note: This is an abbreviated project idea, without notes to start your background research or a procedure for how to do the experiment. You can identify abbreviated project ideas by the asterisk at the end of the title. If you want a project idea with full instructions, please pick one without an asterisk.

Abstract

Here's a puzzle you may have heard before which you can build as a simple electric circuit. First, the puzzle: a farmer is traveling to market with his cat, a chicken and some corn. He has to cross a river, and the only way to cross is in a small boat which can hold the farmer and just one of the three items he has with him. The problem is, he has to be very careful about what he chooses to leave behind at any time. If the cat and chicken are left alone, the cat will eat the chicken. If the chicken and the corn are left alone, the chicken will eat the corn. To solve the puzzle, you must show how the farmer can get himself and his three items across the river without losing any of them. The goal of this project is to design a simple electrical circuit that follows the puzzle. You'll need a 6 V battery, a flashlight bulb, a bulb holder, some connecting wire, and four toggle switches: 3 SPDT (single-pole, double throw) and 1 DPDT (double-pole, double throw). Each switch represents one of the items: the farmer, the cat, the chicken and the corn (you have to figure out which need to be SPDT switches and which one needs to be a DPDT switch). The switches are mounted on a small panel, in a horizontal row (representing the river, which you can draw in). Each switch is labeled ("Farmer", "Cat", "Chicken", "Corn"). The circuit is to be designed so that if either of the problematic pairs (cat-chicken, or chicken-corn) are left alone on the same side of the river, the light bulb lights up, indicating an incorrect solution (you can add a 6 V buzzer, too, if you like). Since the boat can hold only two items, players can use only two switches per "move". Irwin Math's book, Wires and Watts: Understanding and Using Electricity has the solution (Math, 1981, 67–70), but see if you can figure this one out on your own.

Bibliography

Math, I., 1981. Wires and Watts: Understanding and Using Electricity. New York, NY: Charles Scribner's Sons.

Variations


Last edit date: 2006-12-26 13:21:24


Career Focus

science career image If you like this project, you might want to think about career opportunities in Electricity & Electronics.

Electricians are the people who bring electricity to our homes, schools, businesses, public spaces, and streets—lighting up our world, keeping the indoor temperature comfortable, and powering TVs, computers, and all sorts of machines that make life better. Electricians install and maintain the wiring and equipment that carries electricity, and they also fix electrical machines. Learn more about this career: Electrician.




Join Science Buddies

Become a Science Buddies member! It's free! As a member you will be the first to receive our new and innovative project ideas, news about upcoming science competitions, science fair tips, and information on other science related initiatives.


Support Science Buddies

If this website has helped you, won't you consider a small gift so we may continue developing resources to help teachers and students?

 



 

Science Buddies gratefully acknowledges its Presenting Sponsor
 
It's free! As a member you will be the first to receive our new and innovative project ideas, news about upcoming science competitions, science fair tips, and information on other science related initiatives.


Science Fair Project Home      Our Sponsors      Partners      About Us      Volunteer      Donate      Contact Us      Research Grants & Outreach      Site Map

Science Fair Project Ideas      Science Fair Project Guide      Ask an Expert      Blog      Teacher Resources      Parent Resources      Student Resources      Science Careers     


Privacy Policy Science Buddies

Copyright © 2002-2009 Kenneth Lafferty Hess Family Charitable Foundation. All rights reserved.
Reproduction of material from this website without written permission is strictly prohibited.
Use of this site constitutes acceptance of our Terms and Conditions of Fair Use.