It’s Electric!Experience the physical phenomenon that has shocked scientists for centuries! Learn how to construct a circuit and design your own light-up wearables. Watch as goop dances under the power of static charge. Trap electricity in a jar to carry home!

Age range: 9-12 yearsFocus: Electricity and Circuits

Introduction

Have you ever heard of a man named Nikola Tesla? He was a Serbian-American scientist living in the late 1800’s who discovered and created many of the pieces of technology we use with electricity today. At a time when most homes still used candles to produce light, Tesla invented an electrical system called alternating current, which is still used today to power homes all over the world. He was one of the greatest minds of the 20th century and his interest began when his cat rubbed against him causing a stinging shock. Have you ever had this happen to you? The same static shock we feel can be found in a much more amplified source of lightening. Experiments with static discharge and lightening were some of the first attempts at understanding electricity. Today we will be conducting experiments that use static electricity as well as completing circuits to show the path electricity needs to take to power up technology.

Activity 1: Dancing Goop

Materials

· Balloons – 1 per child (reusable)· Hand pump – 2 per cart· 2 oz. portion cup with lid – 1 per child· Toothpicks – 1 per child· Cornstarch – 2 tbsp per child· Water – 1 tbsp per child· 1 cup liquid measuring cup, with spout or lip for pouring· Large bowl for mixing· Spoon for mixing

Set Up

Have on your tray one balloon for each child attending along with hand pumps. Be sure to have enough portion cups with lids and toothpicks for each child, as well. Place in the bowl 2 tablespoon for every child attending the party. Do not add the water yet, but measure out one tablespoon of water for every child attending in to the measuring cup.

Directions

1. Distribute the balloons, toothpicks, and portion cups with lids around to the guests.

2. Begin pouring the water in with the cornstarch slowly. Add it a little at a time, gauging how the fluid is coming together.

3. Mix carefully with the spoon or with your hands to gauge whether it has reached a non-Newtonian state.

4. Walk around the table and pour a portion of the fluid into each portion cup for the children to experiment with. They can test pouring it out and putting it back in the cup.

5. Once they have had a chance to test the properties of the non-Newtonian fluid, have guests pump up their balloons.

6. Charge the inflated balloons by rubbing on clothes or hair.7. Once charged, have guests place their toothpicks into the fluid, then hold up to the balloon

to watch it move.

Explanation

When you rub the balloon against your hair or clothes, you are giving it extra electrons. The addition of these electrons gives the balloon a negative charge. Meanwhile, the cornstarch, having identity issues over whether to be a liquid or a solid, has a neutral charge. When something has a negative charge it repels the electrons of other objects while attracting protons. When a neutrally charged object is light enough in mass, like our cornstarch, the negatively charged balloon attracts the neutral charge towards it. Try attracting the cornstarch when it’s in the cup or bowl. It won’t work. This is because it now has a heavier mass than the negatively charged balloon can pull. This is why you need to drip the cornstarch off of the toothpick, it means there are fewer molecules for it to adhere to.

Non-Newtonian fluid: a liquid with flow properties which differ in any way from a Newtonian fluid. Also known as a fluid that exhibits properties of a liquid and a solid. It can take the shape of vessels and flow like a liquid, while being dense enough to not easily penetrate and can be picked up and handled.

Static charge: the imbalance of electric charges within or on the surface of a material.

References:

https://www.youtube.com/watch?v=HAR90LDb-Uc

http://www.stevespanglerscience.com/lab/experiments/electric-cornstarch

Activity 2: Leyden Jar

Warning: This experiment deals with discharging a static electric shock with your hands. Be certain to communicate to party participants that they will get shocked if they follow all the steps of the experiments.

Materials

· Small film canister with lid – 1 per child· Large paper clip – 1 per child

· Aluminum foil – 1 1.5” x 4.5” strip per child· Double sided tape – 1 per every 2 children· Small safety scissors – classroom set· Water – about 2 tbsps. per child· Dixie cups – 1 per child· PVC pipe cut to 12 inch length – 1 per every 2 children· Fake fur squares – 1 per every 2 children

Set Up

On a tray have enough film canisters, lids, paper clips, double sided tape, and scissors for each child. Pre-cut several large strips of aluminum foil to pass around. For the water, you will fill each Dixie cup 1/3 of the way full with one cup for each child. Have out your PVC pipes and fake fur squares.

Directions

1. Begin by talking about how in the first experiment the balloon’s negative charge would be lost over time and question how you might keep a charge stored to use for later. What does this device remind you of?

2. Distribute to each child a film canister with lid, a paper clip, a cup of water, a strip of aluminum foil, and a pair of scissors.

3. Begin by measuring out the aluminum foil needed to wrap the base of your canister with and cut off any access foil. Make sure to leave a gap between the top of the canister and the foil, if wrapped too high this experiment will not work.

4. Take two long strips of double sided tape and wrap them around the body of the canister.5. Wrap your foil strip around the tape, pressing firmly so there is high contact between the

foil and the canister.6. Place your lid on the film canister to stabilize for the next step. Begin by pulling the open

end of the paperclip outward and press it straight (fig 1). Carefully holding the film canister in place, puncture the paperclip through the lid of the canister (fig 2).

Fig 2:

Fig 1:

7. Take the lid off of your jar and pour in the water. Wipe down any water that may of transferred to the outside of the jar, it needs to be dry before you proceed. Replace the lid on the jar, listen for the snap that it is tightly closed.

8. Take your PVC pipe in hand and begin to rub it with the fake fur. Listen for the crackle and pop of the static charge building.

9. After a few seconds of rubbing, run the PVC pipe across the sides of the paperclip.10. Repeat steps 8 and 9 a few times to build up a static charge inside the Leyden jar.11. To demonstrate that the Leyden jar has worked, we must discharge the static electricity.

To do this we will carefully hold the jar touching the aluminum foil and with the same hand, touch a finger or knuckle to the paperclip. You will hear and feel the shock or spark of discharge from the Leyden Jar.

Explanation

The Leyden Jar, historically, was the original form of a capacitor, or more commonly known as a battery. It was a device made out of glass, metal, and water developed in the University of Leiden in Germany. The science of what is happening begins with the static charge. Just like with our balloon, we are building a negative charge on the PVC pipe. We then transfer this charge into the Leyden jar through the paperclip. The paperclip, being metal and set at a neutral charge, conducts this electricity into the jar. Once inside the water stores and conducts the charge, but it stops when it encounters the plastic walls of the insulating film canister lined with the positively charged aluminum foil. These two barriers do not allow the electric charge to travel any further and keep them stored inside the jar. In order for the static charge to be released, we just introduce another conductor to the paperclip, which in this case are our fingers. We are creating a circuit with our hand. With one finger on the positively charged aluminum foil and one finger on the negatively charged paperclip, we complete the circuit necessary to discharge our stored static electricity. This is the shock we feel and sometimes can even see when we touch the Leyden jar.

References:

http://en.wikipedia.org/wiki/Leyden_jar#Design

http://www.magnet.fsu.edu/education/tutorials/java/leydenjar/

Activity 3: Circuitry Blocks

Materials

· Circuitry block kit – 3 kits per cart· 2 AA batteries

Set Up

Have enough circuitry boards available depending on the size of the party. For a party of 10, use 2 kits for groups of five to work on. For a party of 15, use 3 kits. For a party of 30, use six kits.

Directions

1. Discuss how a circuits works, see below.2. Experiment within teams of five to make the light turn on the circuitry block.

Explanation

When electricity is stored within a battery cell, like our Leyden jars, it is ready to be discharged or released into a conductor. It has what scientists call, potential energy. With our Leyden jar, our hands acted as a conductor. To be a conductor to electricity a material or object needs to be able to help the flow of the electric current. The opposite of a conductor is an insulator. The plastic coatings seen on electrical wires are an example of an insulator, because they do not allow electric current to pass through.

Using insulators and conductors we can build a circuit. What does the word circuit sound like? In order to move the electricity from our battery to a piece of technology we must make a circular path for it to follow. A circuit is usually made by linking electrical components together with pieces of wire cable. Thus, 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. Similarly, if the switch is turned off, no electricity can flow. This is why a switch is sometimes called a circuit breaker.

A current of electricity is a steady flow of electrons. When electrons move from one place to another they carry electrical energy with them. In order for the electrons to flow there needs to be a push behind it called electromotive force. Our battery generates this force and is termed in volts of how much it can push electrons forward in to the circuit. When electrons are pushed out of the negative terminal of the battery, they are attracted to follow the circuit to the positive terminal where there are less electrons stored. Along the way in our circuit we may have placed a light, which is has a filament inside it which conducts those electrons till it glows white hot, producing light as a byproduct.

References:

https://www.khanacademy.org/science/physics/electricity-and-magnetism/v/circuits-part-1

I recommend watching just the first video on circuits. The other three lessons get very highly technical for those training to become electricians. However the Khan Academy does give a comprehensive overview of circuitry. There are also videos in this lesson plan that includes information on static electricity, potential energy, voltage, and capacitance.

OR: https://www.youtube.com/watch?v=vK0uAW8usco Bill Nye, for classic science knowledge!

How light bulbs work: https://www.youtube.com/watch?v=-MYB8butQwQ

Activity 4: Light-Up Wearables

Materials

· Small safety scissors – classroom set· Foam strips and pieces – 1 1” x 2.5” strip per child· Alligator clips – 1 per child· Decoration (feathers, sequins, stickers, etc.)· Pipe cleaners – 1 per child· CR2032 button battery – 1 per child· 5 mm LED light – 1 per child

Set Up

Place on your tray one button battery, one LED light, one strip of craft foam, and one alligator clip per every child attending the party. On a second tray have decorations to be shared between every two participants.

Directions

1. Begin by making observations of the battery. Do you see the plus and negative sign? How do we think this battery is similar to our Leyden jar? How is it different?

2. Test the LED light against the battery. What does it take to make the light turn on? Which “leg” of the LED should be touching which side of the battery?

3. Once determined, longer leg to positive side, sandwich your battery and LED with the small strip of craft foam. Take the alligator clip to hold the battery and light in place.

4. We now have a circuit and base for our light-up wearable. Kids may now decorate using the stickers and other materials.

5. Once decorated you may either clip the battery and light combo on to a child’s shirt or string a pipe cleaner through the clip’s open wires to make a bracelet or ring.

Explanation

As we experimented with the circuitry boards, we are creating another circuit. This time the circuit is smaller, as the anode and cathode of the LED conduct the flow of electrons in and out of the light. Our insulator is the electrical tape. The light will stay on for as long as there is stored energy in the battery and the legs of the LED are touching the correct terminals.