|Dirtmeister's Science Lab on Circuits|
Grade Levels: K - 5
Background Information: Circuits
Managing Time & Students
Related Web Sites
The Dirtmeister is your personal guide to hands-on science exploration in the classroom. By participating in Dirtmeister's Science Labs, kids have the opportunity to experience science firsthand. The steps in completing the challenge follow the same methodology used by scientists in solving problems. After reading the question, students are encouraged to formulate hypotheses. With science expert Steve Tomecek (the "Dirtmeister") serving as facilitator, students complete the hands-on investigation and check their results against their predictions.
Teachers who participate in the challenge also have the opportunity to gain valuable experience in teaching inquiry-based science because each new challenge helps to reinforce basic science concepts. For personal advice and support from Steve, join the Hands-On Science discussion in the Teacher Center.Top of Page
Background Information on Circuits
In this Science Lab, we explore the wonderful world of circuits. Using a simple setup of batteries and bulbs, students will discover how connections in a series circuit can increase and decrease voltage. Series circuits are the simplest forms of circuits because, as the name suggests, all the components are attached in one direct line, or a series. As a result, if there are any breaks in the circuit, the whole circuit will go dead. That's because there is no alternative route for the electricity to flow. If you've ever put up those little holiday lights, you know how annoying a series circuit can be because if one bulb goes out, they all do. That means testing all the bulbs until you find the guilty culprit. On the other hand, in most buildings, if one light goes out, the rest stay on. This is because the circuit wiring is parallel, which means there is a second route for the electricity to follow.
When working with batteries and series circuits, it's very important to know the direction of the flow of electricity. Batteries produce something called direct current (DC), which means that all the electrons flow out of the negative end and return back into the positive. If two or more batteries are hooked up together in a series circuit, they have to be arranged so that the positive (+) end of one battery is touching the negative (-) end of the next. You may have noticed that if you put batteries in a radio or other portable device that uses many batteries, there is always a little chart showing which way they must go in. This is to insure that the electron flow is all in the right direction. If even one battery is turned the wrong way, the circuit won't work!
Note: The word "cell" is the proper term for a single device like a "D" or "C" cell. Batteries are devices that have more than one cell put together, like the battery in your car that usually has six cells. For simplicity, we'll just call all these devices batteries.
All batteries from the smallest button battery to the one that starts your car put out a certain amount of electricity called voltage. This number, along with the positive (+) and negative (-) ends, is printed somewhere on the battery. A typical "D" or "C" cell puts out 1.5 volts. However, when the batteries are hooked up in series, the voltage increases. In other words, two "D" cells in series give you three volts, and four cells give you six volts. As a result, when you add batteries to a series circuit with only one bulb, the bulb gets brighter because it has more electricity running through it. Of course, if you put too many batteries together, you'll burn out the bulb because the voltage will be too high! That's why every bulb has a voltage rating on it.
On the other hand, since lightbulbs use electricity, the more bulbs you hook up in a series circuit, the dimmer the light from the individual bulbs will get. Each bulb offers a certain resistance to the flow of electrons, and just like the voltage, the resistance increases as more bulbs are added. The greater the total resistance, the harder it is for the electrons to make it around the circuit, so the bulbs will be dimmer. Only when the numbers of bulbs and batteries in a series circuit are balanced will all the components work at maximum efficiency.Top of Page
Learning Outcomes/National Standards Correlations
The Dirtmeister's Science Lab on circuits helps students meet the following science-content standards as set forth by the National Research Council of the National Academy of Sciences:
Managing Time and Students
Classroom management is always a critical factor for any successful lesson, and the Dirtmeister's Science Lab is no exception. The following strategies will help to maximize the use of the activity in various classroom situations:
Here are some suggestions to enhance the experience of Dirtmeister's Science Lab for your students:
Extensions on Circuits
General ExtensionsGrades K-2:
The following Scholastic supplemental materials can be used in conjunction with Dirtmeister's Science Lab.
Call Scholastic directly at 1-800-724-6527 to order and for more information.Top of Page
Related Web Sites
General Science Sites
Science and Technology for Children Curriculum
The Natural History Museum (London) Edison National Historic Site Endangered Species Program
Edison National Historic Site
Endangered Species Program
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