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It's Electric! The power of charges (Christine Hirst)

Christine Hirst

Introduction

Atoms, and all matter, are made up of the fundamental particles: electrons, protons, and neutrons. Electrons are negatively charged, protons are positively charged, and neutrons have no charge. The charge on a proton is equal in magnitude to the charge on an electron. The nucleus of an atom, in general, is composed of protons and neutrons. The nucleus is surrounded by clouds of electrons. Whenever most objects are left undis- turbed for an unspecified length of time, their protons and electrons are equal in number and the objects are regarded as having balanced electrical charges.

However, some objects will pick up excess electrons from material rubbed on them; still others transfer excess electrons to material rubbed against them. In the above discrepant event, when the balloon is rubbed on the wool, the balloon picks up excess electrons from the wool. Now the balloon is regarded as being negatively charged. The wall may be regarded as a neutrally charged surface.. Both positively and negatively charged objects are capable of being attracted to neutrally charged objects. The balloon was attracted to the wall surface, and thus, stuck to it. The two balloons moved away from one another because the similar charges they were carrying repelled each other. Like charges repel, unlike charges attract. In both cases, static electricity was at work.

Principles:

Static Electricity, particle charges

1. electricity
2. electrical  charges
3. movement/transfer of electrons

Standards

• Physics 5.D Students Know charged particles are sources of magnetic fields and subject to forces from electric fields and other charges
Objectives
• Students will be able to determine the variables that affect how positive and negative objects interact.
• ·Students will be able to predict how positive and negative objects will interact.
• Students will be able to diagram and predict everyday occurrences of static and the relationship to electron transfer

Prior knowledge & experience:

• Static electricity makes your hair stand up
• Lightening is an electric charge, or response to charges
• opposite charges attract, like repel

• atoms are made up of a nucleus-protons and neutrons, and electrons
• protons have a positive charge, neutrons are neutral and electrons are negative

Root question:

1. What is the cause of lightening?
2. What is static electricity?
3. What is the relationship between atomic charge and electricity?
4. What is the connection between lightening and thunder?

Target response:

Electricity and static charge is a response to oppositional atomic charges.

Common Misconceptions:

• Lightening is soundless
• lightening is electricity
When in fact-lightening is the sound of thunder!  Most students know that there is a connection between lightening and thunder, but since light travels faster than sound, we see lightening before we hear the thunder.

Lightening is actually the sound of the rapidly expanding air, which is in effect a sonic boom.

Possible Extensions:

Students will create their own opposing charges and allow balloons to repel each other.

1. Have students each take a balloon and tie them together.
2. Students will apply a charge to their balloons
3. Use a sharpie to indicate where charge has been applied
4. Touch balloons to each other in area with applied charges and Viola!

Application

Tell students to look for metal stripping in the middle of the road in front of a toll booth. Ask students what purpose the metal strands have. (when vehicles travel on the highway, they build up static electricity. As vehicles rub on the strands of metal, the stored static electricity is discharged into the ground. If the strips were not present, a spark would pass between the driver and the toll booth operator.)

Photographs and Movies

Put all photos in the class Picasa Album and reference here.  Do not upload the photos directly to this wiki as there is not enough memory in the website.

Put all movies in your own Youtube account.  Make sure that the account is set for public viewing. Insert the Youtube videos here.

References

Electrostatics

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Christine Hirst,
Sep 28, 2011, 8:36 PM