Key Concepts

Atoms are made of very tiny pshort articles referred to as proloads, neutrons, and also electrons.Protons and also neutrons are in the center of the atom, making up the nucleus.Electrons surround the nucleus.Prolots have a positive charge.Electrons have an unfavorable charge.The charge on the proton and also electron are exactly the same dimension however opposite.Neutrons have actually no charge.Due to the fact that opposite charges attract, proloads and electrons lure each various other.

You are watching: Would you expect two electrons to attract or repel

Summary

Students will put a static charge on a strip of plastic by pulling it between their fingers. They will watch that the plastic is attracted to their fingers. Students will certainly be presented to the idea that rubbing the spilgrimage with their fingers resulted in electrons to relocate from their skin to the plastic offering the plastic a negative charge and their skin a positive charge. Thstormy these activities, students will certainly be introduced to some of the qualities of electrons, proloads, and neutrons, which comprise atoms.

Objective

Students will certainly have the ability to describe, in regards to electrons and proloads, why a charged object is attracted or repelled by an additional charged object. They will likewise have the ability to explain why a charged object can even be attracted to an uncharged object. Students will certainly additionally be able to describe that the attractivity between positive protons and also negative electrons holds an atom together.

Evaluation

Downfill the student activity sheet, and also distribute one per student when mentioned in the task. The task sheet will certainly serve as the “Evaluate” component of each 5-E leskid setup.

Safety

Be sure you and the students wear appropriately fitting goggles.

Materials for Each Group

Plastic grocery bagScissorsInflated balloonSmall pieces of paper, confetti-size

Materials for Demonstration

Sink Balloon
Explore

Do an task to show that electrons and protons attract each other.

Students can check out proof of the charges of prolots and electrons by doing an activity via static electricity.

Note: When two materials are rubbed together in a static electrical power activity, one material tends to shed electrons while the various other material tends to obtain electron. In this activity, humale skin often tends to shed electrons while the plastic bag, made of polyethylene, tends to gain electrons.

Concern to investigate

What renders objects tempt or repel each other?

Materials for each group

Plastic grocery bagScissors

Procedure, component 1

Charged plastic and charged skinCut 2 strips from a plastic grocery bag so that each is about 2–4 cm wide and also around 20 cm long.

Hold the plastic spilgrimage firmly at one end. Then master the plastic spilgrimage in between the thumb and fingers of your various other hand as presented.

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Quickly pull your height hand up so that the plastic sexpedition runs via your fingers. Do this three or 4 times.Allow the strip to hang dvery own. Then lug your other hand close to it. Write “attract” or “repel” in the chart on the activity sheet to describe what happened.

Expected results

The plastic will be attracted to your hand and also relocate towards it. Students may alert that the plastic is likewise attracted to their arms and sleeves. Let students understand that later on in this lesboy they will certainly investigate why the plastic strip is likewise attracted to surdeals with that have actually not been charged (neutral).

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Note: If students discover that their plastic spilgrimage does not move toward their hand also, it have to not have been charged well enough. Have them attempt charging their plastic strip by holding it dvery own on their pants or shirt and then conveniently pulling it with the various other hand. Then they must test to view if the plastic is attracted to their garments. If not, students should try charging the plastic aobtain.

Explore

Have students investigate what happens as soon as a rubbed plastic spilgrimage is held near a desk or chair.

Procedure, part 2

Charged plastic and neutral deskCharge one strip of plastic the exact same way you did previously.

This time, lug the plastic sexpedition toward your desk or chair.

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Write “attract” or “repel” in the chart.

Expected results

The plastic moves towards the desk.

Explain to students why the plastic is attracted to the desk. The answer takes a couple of measures, so you deserve to overview students by drawing or projecting a amplified illustration of the plastic and desk.

After pulling the plastic between their fingers, the plastic gains added electrons and a negative charge. The desk has actually the very same number of protons as electrons and also is neutral. When the plastic gets cshed to the desk, the negatively charged plastic repels electrons on the surface of the desk. This renders the surface of the desk near the plastic slightly positive. The negatively charged plastic is attracted to this positive location, so the plastic moves towards it.

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Have students charge two pieces of plastic and hold them near each various other to check out if electrons repel one other.

Ask students to make a prediction:

What carry out you think will certainly happen if you charge two strips of plastic and lug them close to each other?

Procedure, component 3

2 pieces of charged plasticCharge 2 strips of plasticSlowly lug the two strips of plastic close to each various other. Write “attract” or “repel” in the chart on the activity sheet.
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Expected results

The strips will certainly move amethod or repel each other. Due to the fact that both strips have actually additional electrons on them, they each have actually extran adverse charge. Because the exact same charges repel one an additional, the strips relocate ameans from each various other.

Ask students:

What occurred when you lugged the two pieces of plastic near each other?The ends of the strips relocated ameans from each other.Use what you know about electrons and charges to describe why this happens.Each strip has added electrons so they are both negatively charged. Since choose charges repel, the pieces of plastic repelled each various other.Explore

Have students use their understanding of proloads and also electrons to define what happens as soon as a charged balloon is carried close to pieces of paper.

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Materials for each group

Inflated balloonSmall pieces of paper, confetti-size

Procedure

Rub a balloon on your hair or clothing. Extra Extend

Demonstrate exactly how electrons deserve to lure a stream of water.

Either perform the adhering to demonstration or display the video Balloon and also Water.

Materials for the demonstration

SinkBalloon

Procedure

Rub a balloon on your shirt or pants to provide it a static charge. Turn on the faucet so that tbelow is a really thin stream of water. Slowly carry the charged part of the balloon cshed to the stream of water.

Expected results

The stream of water must bend as it is attracted to the balloon.

Ask students:

What did you observe when the charged balloon was organized close to the stream of water?The stream of water bent towards the balloon. Use what you know around electrons, protons, and also charges to define why this happens.When you rub the balloon on your hair or garments it picks up additional electrons, offering the balloon a negative charge. When you carry the balloon close to the stream of water, the electrons from the balloon repel the electrons in the water. Because even more protons are at the surface of the water, it has actually a positive readjust. Opposites attract, so the water moves towards the balloon.