Electronic devices might seem too complicated to understand how they work, but in reality are just collections of wires, resistors, capacitors, and batteries, forming circuits that allow for the transfer of energy. Flashlights, toasters, blowdryers, and radios all have one thing in common; they rely on electric circuits to function correctly.
There are two main types of energy: static and current. When electricity gathers in one place, it is considered to be static. Energy that travels from one place to another is current. For an electric current to happen, there must be a circuit. A circuit is a closed path or loop around which an electric current flows. Circuits are usually made by linking electrical components together with pieces of wire cable.
In a flashlight, there is a simple circuit with a switch, a lamp, and a battery linked together by a few short pieces of copper wire. When you turn the switch on, electricity flows around the circuit. If there is a break anywhere in the circuit, electricity cannot flow. If one of the wires is broken, for example, the lamp will not light. This concept can be observed in most electrical devices. Many circuits have a switch so that they can be turned on and off. When the switch is off, it makes a gap in the circuit and the electrons are not able to flow around. When the switch is turned on, it closes the gap and the electricity is able to move and make the device work.
Materials such as copper metal that conduct electricity (allow it to flow freely) are called conductors. Materials that don't allow electricity to pass through them so readily, such as rubber and plastic, are called insulators. Metals like copper have "free" electrons that are not bound tightly to their parent atoms. These electrons flow freely throughout the structure of copper and this is what enables an electric current to flow. In rubber, the electrons are more tightly bound. There are no "free" electrons and, as a result, electricity does not really flow through rubber at all.
Electric Play Dough!
In a flashlight, there is a simple circuit with a switch, a lamp, and a battery linked together by a few short pieces of copper wire. When you turn the switch on, electricity flows around the circuit. If there is a break anywhere in the circuit, electricity cannot flow. If one of the wires is broken, for example, the lamp will not light. This concept can be observed in most electrical devices. Many circuits have a switch so that they can be turned on and off. When the switch is off, it makes a gap in the circuit and the electrons are not able to flow around. When the switch is turned on, it closes the gap and the electricity is able to move and make the device work.
Materials such as copper metal that conduct electricity (allow it to flow freely) are called conductors. Materials that don't allow electricity to pass through them so readily, such as rubber and plastic, are called insulators. Metals like copper have "free" electrons that are not bound tightly to their parent atoms. These electrons flow freely throughout the structure of copper and this is what enables an electric current to flow. In rubber, the electrons are more tightly bound. There are no "free" electrons and, as a result, electricity does not really flow through rubber at all.
Electric Play Dough!
In this activity, we can make an electric circuit at home using play dough, batteries, and some small LED lights! If stored properly, the dough should keep for several weeks, so you can repeat the experiment as many times as you’d like. Here’s what you’ll need:
1 cup of water
½ cup of distilled water
3 cups of flour
½ cup of sugar
¼ cup of salt
4 Tbsp. of vegetable oil
3 Tbsp. cream of tartar or 9 Tbsp. of lemon juice
Food coloring (optional)
Medium sized pot
2 spade terminals
Wire stripper/terminal crimper
Battery pack and batteries
LEDs
First, we’ll need to attach the spade terminals to the leads of the battery pack. Make sure to get an adult to help with this process so no one gets hurt! Slide the wire leads into the openings of the spade terminals. Use the wire stripper/crimping tool to crimp the open end closed and secure the connection.
Next, we need to prepare our conducting dough and insulating dough! Starting with the conducting dough, mix one cup of water, one cup of flour, the salt, cream of tartar/lemon juice, one tablespoon of vegetable oil, and your choice of food coloring in a medium sized pot. While continuously stirring, cook the mixture over medium heat. Soon the dough will become chunky, so keep stirring until the mixture forms a ball in the center of the pot. Carefully remove the ball from the pot and place it onto a lightly floured surface. Use a rolling pin to flatten the dough so it has a chance to cool off a little before you start kneading. Slowly knead the remaining flour into the ball until you’re satisfied with the consistency.
1 cup of water
½ cup of distilled water
3 cups of flour
½ cup of sugar
¼ cup of salt
4 Tbsp. of vegetable oil
3 Tbsp. cream of tartar or 9 Tbsp. of lemon juice
Food coloring (optional)
Medium sized pot
2 spade terminals
Wire stripper/terminal crimper
Battery pack and batteries
LEDs
First, we’ll need to attach the spade terminals to the leads of the battery pack. Make sure to get an adult to help with this process so no one gets hurt! Slide the wire leads into the openings of the spade terminals. Use the wire stripper/crimping tool to crimp the open end closed and secure the connection.
Next, we need to prepare our conducting dough and insulating dough! Starting with the conducting dough, mix one cup of water, one cup of flour, the salt, cream of tartar/lemon juice, one tablespoon of vegetable oil, and your choice of food coloring in a medium sized pot. While continuously stirring, cook the mixture over medium heat. Soon the dough will become chunky, so keep stirring until the mixture forms a ball in the center of the pot. Carefully remove the ball from the pot and place it onto a lightly floured surface. Use a rolling pin to flatten the dough so it has a chance to cool off a little before you start kneading. Slowly knead the remaining flour into the ball until you’re satisfied with the consistency.
For the insulating dough you’ll need to mix 1 ½ cups of flour, ½ cup of sugar, and 3 tablespoons of vegetable oil in a clean mixing bowl. Make sure to set aside some flour for later! Add about one tablespoon of distilled water into the mixture and stir. Repeat this process until most of the water is absorbed by the mixture. Next, gather and knead the mixture into one lump. Knead more water into the dough until it becomes sticky. Now we can knead the flour we set aside earlier into the dough until it reaches the desired texture! (You can also insulate the dough using plastic wrap, as shown in the picture above!)
To make a simple series circuit, roll up two pieces of the conductive dough and place a wire into each one; making sure the two pieces of dough do not touch. Then, close the circuit by placing a wire from an LED into each piece of dough. If the LED doesn’t light up, flip it around! LEDs only allow energy to flow in one direction. You’ve just created a series circuit!
To make a simple series circuit, roll up two pieces of the conductive dough and place a wire into each one; making sure the two pieces of dough do not touch. Then, close the circuit by placing a wire from an LED into each piece of dough. If the LED doesn’t light up, flip it around! LEDs only allow energy to flow in one direction. You’ve just created a series circuit!
To open up the circuit, remove one of the battery pack wires. The light will go out because the circuit has been broken. Close the circuit again by re-inserting the wire into the dough. Now push the pieces of dough together. What happens? Now you have a short circuit. To fix this, place a piece of insulating dough between the conducting pieces. Why does the light turn on again?
References:
http://discoverykids.com/articles/how-do-electric-circuits-work/
http://www.pbs.org/parents/adventures-in-learning/2014/02/electric-play-dough/
Image Credits:
Zinn, Kathy. “Small Black Flashlight”. Released into the public domain. Uploaded on 9/12/17 from publicdomainpictures.net
Lewis, Darren. “Kneading Cookie Dough”. Released into the public domain. Uploaded on 9/13/17 from publicdomainpictures.net
Activity example images property of Discovery Express Kids LLC.
References:
http://discoverykids.com/articles/how-do-electric-circuits-work/
http://www.pbs.org/parents/adventures-in-learning/2014/02/electric-play-dough/
Image Credits:
Zinn, Kathy. “Small Black Flashlight”. Released into the public domain. Uploaded on 9/12/17 from publicdomainpictures.net
Lewis, Darren. “Kneading Cookie Dough”. Released into the public domain. Uploaded on 9/13/17 from publicdomainpictures.net
Activity example images property of Discovery Express Kids LLC.
