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ELEMENTARY SCIENCE PROGRAM

MATH, SCIENCE & TECHNOLOGY EDUCATION

A Collection of Learning Experiences

ELECTROMAGNETISM

Electromagnetism Student Activity

Book Name__________________________________________________________ This learning experience activity book is yours to keep. Please put your name on it now. This activity book should contain your observations of and results from your experiments. When performing experiments, ask your teacher for any additional materials you may need. 1

TABLE OF CONTENTS

Activity Sheet for L.E. #1 - KWHL...........................................................................2

Activity Sheet for L.E. #2 - Magnetic Attraction.......................................................3

Activity Sheet for L.E. #3 - Permanent Magnets and their magnetic force fields ............................................................................4-6 Activity Sheet for L.E. #4 - Detecting a Magnetic Field From a Permanent

Magnet with a Permanent Magnet ...............................7

Activity Sheet for L.E. #5 - Detecting a Magnetic Field From a Permanent Magnet

with a Compass............................................................8-9

Activity Sheet for L.E. #6 - Building and Testing an Electromagnet........................10-11 Activity Sheet for L.E. #7 - Electromagnets, Magnets, and Their Magnetic

Force Fields ..................................................................12-13

Activity Sheet for L.E. #8 - Detecting a Magnetic Field From an Electro-

Magnetic with a Permanent Magnet..............................14

Activity Sheet for L.E. #9 - Detecting a Magnetic Field From an Electro-

Magnet With a Compass...............................................15

Activity Sheet for L.E. #10 - Electromagnets at Work - Buzzer...............................16-19 Activity Sheet for L.E. #11- Electromagnets at Work - Electric Motor .....................20-22

Electromagnetism Student Assessment.................................................................23-26

Student Self Assessment........................................................................................27

Glossary..................................................................................................................28-29

2 Activity Sheet for Learning Experience #1 Name______________________

MAGNETISM

Magnets create a force called magnetism. The ends of a magnet attract or repel each other and attract some metals particularly iron and steel. This attraction is due to the magnetic pole of magnets. All magnets have a north and south pole. Some magnets occur naturally. A natural magnet found in the ground is called lodestone. Ancient Greeks and Chinese knew about magnetism about 2000 years ago. The Chinese noticed that a piece of lodestone would point north and south when suspended from a string. Many other magnets have been made for and use by man. In the space below write what you know, want to know, and how you might find out about magnets. KWHL

K W H L

List ten or more uses of magnets in or around the home, business, or school.

1.________________________

2.________________________

3.________________________

4.________________________

5.________________________

6.________________________

7.________________________

8.________________________

9.________________________

10._______________________

3 Activity Sheet for Learning Experience #2 Name______________________

MAGNETIC ATTRACTION

Some materials are magnetic and others are not. The electrons of all atoms spin as they move around the nucleus. A spinning electron produces a magnetic field with a north and south pole. Each atom acts like a small magnet. In most materials, the magnetic fields of these atoms cancel each other out, so the material is not magnetic. However, in iron, cobalt, and nickel the magnetic field of each atom is so strong that they group together. List materials below that are attracted or unattracted by magnets.

Attracted Unattracted

Describe what you observed when you did this learning experience? _________ ________________________________________________________________ ________________________________________________________________ 4 Activity Sheet for Learning Experience #3 Name______________________ PERMANENT MAGNETS AND THEIR MAGNETIC FORCE FIELDS In some materials (iron, cobalt and nickel) the magnetic fields of each atom is so strong that they group together to form domains. When all domains are arranged together with their North and South poles aligned in the same direction, the material becomes a permanent magnet. This is the case in an iron bar magnet. A permanent magnet can lose their magnetism if their domains are pushed out of line. This can happen if the magnet is heated or hit with a hammer. The motion of the atoms increases and the domains are pushed out of line. If a piece of iron is brought near a magnet, the domains in the iron bar line up with the magnetic field lines of the magnet. When the magnet is removed, the atoms return to their normal motion. This may cause the domains to return to their original positions. A temporary magnet is an object that stops acting as a magnet when the magnetic field is removed. 5 Activity Sheet for Learning Experience #3 Page 2

1. This learning experience requires a half sheet of copy paper. Prepare the

copy paper by measuring and marking a line 1 cm from each edge. Fold the copy paper along the four edges to form a shallow box. The fold should be 1 cm from the edge. It may be easier to fold the corners if a small cut is made in each corner. Tape the corners. Place one iron magnet on your desk. Cover the magnet with the half sheet of paper that you previously prepared. Obtain a medicine cup with 5 cc of iron filings. Sprinkle the iron filings on the paper above the magnet. Gently tap the paper with the iron filings near the magnet. Each magnet has a North pole and a South pole. The iron filings make the invisible force field around each magnet visible. In the space below, make a drawing of the patterns formed by the iron filings.

2. Place two iron magnets on your desk. Cover the magnets with the half sheet

of copy paper as indicated above. Obtain a medicine cup with 5 cc of iron filings. Sprinkle the iron filings on the copy paper above the magnet. Gently tap the paper with the iron filings near the magnets. Each magnet has a North pole and a South pole. The iron filings make the invisible force field around each magnet visible. When two magnets with like poles (North and North) or (South or South) are placed next to each other, they will repel each other. When two magnets with unlike poles (North and South) or (South and North) are placed to each other they will attract each other. In the space below, make drawing of the patterns formed by the iron filings with the magnets in the attract and repel position.

Repel Attract

6 Activity Sheet for Learning Experience #3 Page 3 All magnets are surrounded by a magnetic region called a magnetic field. The magnetic field is strongest at the poles of the magnet. The magnetic field lines extend from one pole to the other. The arrows show the direction of the magnetic field. If iron was placed near a magnet, it would be most attracted to the north or south pole of the magnet, and it would also be attracted to the field around the magnet. Place 10 cc of iron filings in the clear plastic jar. Close the cap firmly. Place the large rectangular magnet on the side of the jar. Position the jar as shown below. Tap the jar to arrange the iron filings above the magnet. This magnet has its poles on each face of the magnet. Place the magnet in different locations on the outside of the plastic jar. Make a drawing of the iron filings and the magnet that shows the magnetic force field. Choose a position that is different from the one that has been provided.

Your Drawin

g 7 Activity Sheet for Learning Experience #4 Name______________________

DETECTING A MAGNETIC FIELD

FROM A PERMANENT MAGNET WITH A PERMANENT MAGNET

Suspend a rubberized magnet by a string 30 cm long. Masking tape is to be used to attach the rubberized magnet. Experiment with the placement of another rubberized magnet near the suspended magnet. Move the handheld magnet in a variety of ways and observe the action of the suspended magnet. What is your explanation as to why the suspended rubberized magnet moves when another rubberized magnet is brought near it? ____________________ ________________________________________________________________ ________________________________________________________________ The movement of the handheld rubberized magnet may cause the suspended rubberized magnet to rotate. What is your explanation as to why this occurs? ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ 8 Activity Sheet for Learning Experience #5 Name______________________

DETECTING A MAGNETIC FIELD

FROM A PERMANENT MAGNET WITH A COMPASS

Earth as a Magnet

If you hang a magnet by a string, the north seeking pole will always point north because the earth itself is a huge magnet. The magnetic field around a bar magnet is similar to the magnetic field. The Earth's magnetic field is caused by the movement of the molten metals near the Earth's core. A compass is an instrument that uses the Earth's magnetic field to establish direction. A compass has a magnetized needle that turns freely and aligns with the earth's magnetic field. So establishing direction with a compass is effective. 9 Activity Sheet for Learning Experience #5 Page 2 Bring various small objects near the compass. Try a variety of objects other than a magnet. Next bring one of the iron magnets near the compass. Reverse the ends of the iron magnet. Observe what happens to the compass needle. Make a list of all the materials that will move the compass needle. List the materials that will move the compass needle. _____________________ ________________________________________________________________ ________________________________________________________________ What is your explanation as to why the compass needle is attracted to one end of the iron magnet and repelling the other end? ____________________________ ________________________________________________________________ ________________________________________________________________ 10 Activity Sheet for Learning Experience #6 Name______________________

BUILDING AND TESTING AN ELECTROMAGNET

Materials

4 "D" cell batteries

2.1 meter piece of #20 enameled copper wire

30 cm piece of #20 enameled copper wire

Small square abrasive paper

Carriage bolt, ¼-20 2-1/2" long (non-metric)

4 #82 rubberbands

8 Fahnestock clips

Pushbutton switch

20 #1 paper clips

3 small pieces of plastic insulated copper wire

Assemble materials as shown on the illustration below. Use the abrasive paper to sand the enamel coating off the last 2.5 cm of each end of the enameled copper wire. To make the coil, wrap the wire around the carriage bolt as described below. Leave about 20 cm of wire unwrapped. Start just behind the square part of the bolt shaft. Wrap in a counterclockwise direction. Try to keep the enameled wire in the groove of the bolt. Keep the wire as uniform in winding as possible. Use a pushbutton switch in series with the electromagnet. Time out ten seconds. As a measure of the electromagnet's strength, determine the total number of paper clips that the electromagnet will pickup in ten seconds. Release the pushbutton switch disconnecting the electromagnet after ten seconds. Note: The #82 rubberbands are used to hold the Fahnestock clips in place on the battery. The fahnestock clips are used to help connect the wire. Do not leave the electromagnet connected for more than 10 seconds. Longer connection will result in excess drain on the battery and limit the life of the battery. Longer connection will also result in excess heating of the wires and battery. You will need the three pieces of plastic insulated copper wire to connect between each battery.

1. With one "D" cell and 10 turns of wire around the bolt, how many paper clips

will the electromagnet pick up? Test the electromagnets as described above. Wrap an additional 10 turns to make a total of 20 turns. Test with 10, 20, 30, 40, 50, 60, 70, and 80 turns of enameled wire. After wrapping 40 turns of
11 Activity Sheet for Learning Experience #6 Page 2 wire, wrap additional turns on top of the first 40 turns to make a second layer. Record your observations on Chart #1. Students will need to determine the scale for their graph.

2. Next start with one "D" cell and 80 turns of wire around the nail. Test the

electromagnet as described above. Test with 1, 2, 3, and 4, "D" cells in series. Record your observations on Chart #2.

3. Save the electromagnet you have made in this learning experience for use in

Learning Experiences #7, 8, 9, and 10.

Chart #1

10 20 30 40 50 60 70 80

Chart#2

1 2 3 4

Number of Batteries

Compare your results with the rest of

the class. If your results are different, how can you explain the differences?

Note: Check after each test to see if

the carriage bolt has become magnetized. If the electromagnet will pick up paper clip without being connected to the "D" cell, the carriage bolt has become magnetized. To demagnetize the carriage bolt, wrap it on the floor several times.

Students should make their own

scale from the graph. Paper clips picked up

Students should make their

own scale from the graph. Pa p er cli p s p icked u p .

Turns of Wire

# of Paperclips 12 Activity Sheet for Learning Experience #7 Name______________________ ELECTROMAGNETS, MAGNETS, AND THEIR MAGNETIC FORCE FIELDS This learning experience requires a half sheet of copy paper. Prepare the copy paper by measuring and marking a line 1 cm from each edge. Fold the paper along the four edges to form a shallow box. The fold should be 1 cm from the edge. It may be easier to fold the corners if a small cut is made in each corner. Tape the corners. Connect the electromagnet from Learning Experience #6 in series with two "D" cell batteries and the pushbutton switch. Hold the electromagnet in a vertical position with the large end up. Cover the large end of the carriage bolt with the shallow paper box. Hold the pushbutton in the on position for ten seconds. Obtain a medicine cup with 5 cc of iron filings. Sprinkle iron filings on the copy paper above the magnet. Observe the patterns formed by the iron filings. Gently tap the copy paper near the magnet. The iron filings make the invisible force field around each magnet visible. In the space below, make a drawing of the patterns formed by the iron filings. Place two iron magnets vertically under the paper tray and repeat the application of the iron filings as you did above. Observe the action of the iron filings. The iron filings make the invisible force field around each magnet visible. In the space below, make a drawing of the patterns formed by the iron filings. 13 Activity Sheet for Learning Experience #7 Page 2 Place 10 cc of iron filings in the clear plastic jar. Close the cap firmly. Connect the electromagnet from Learning Experience #6 in series with four "D" cell batteries and the pushbutton switch. Hold the electromagnet in a vertical position with the large end up. Position the jar as shown below. Hold the pushbutton in the on position for ten seconds. Tap the jar to arrange the iron filings above the magnet. Place the magnet in different locations on the outside of the plastic jar. Make a drawing of the iron filings and the electromagnet that shows the magnetic force field. Choose a position that is different from the one that has been provided.

Your Drawing

14 Activity Sheet for Learning Experience #8 Name______________________

DETECTING A MAGNETIC FIELD FROM AN

ELECTROMAGNET WITH A PERMANENT MAGNET

Suspend a rubberized magnet by a string 30 cm long. Connect the electromagnet from Learning Experience #6 in series with two "D" cell batteries and the pushbutton switch. Hold the electromagnet in a vertical position with the large end up. Experiment with the placement of the electromagnet about 5 cm under the suspended magnet. Press the pushbutton and quickly release. Experiment with pressing the pushbutton to move the suspended magnet.

Observe the action of the suspended magnet.

What is your explanation to why the electromagnet moves when another rubberized magnet is brought near it? _________________________________ ________________________________________________________________ ________________________________________________________________ The movement of the handheld rubberized magnet may cause the electromagnet to rotate. What is your explanation to why this occurs? ____________________ ________________________________________________________________ ________________________________________________________________ 15 Activity Sheet for Learning Experience #9 Name______________________

DETECTING A MAGNETIC FIELD FROM AN

ELECTROMAGNET WITH A COMPASS

Hans Christian Oersted was a Danish physicist, who in 1820, noticed that when a compass was placed near an electric current, the compass needle no longer pointed north. It would turn 90 degrees. He concluded that since the compass follows a magnet, the wire with the current flowing through it acts as a magnet. The compass needle will turn in a clockwise direction if electrons flow up the current carrying wire. The magnetic field exerts force in a clockwise direction. When electrons flow down the wire, the magnetic field exerts a force in a counter clockwise direction. Therefore, the compass needle will move in a counter clockwise direction. Place a compass on a non-metal surface away from iron and steel objects. Connect the electromagnet from Learning Experience #6 in series with one "D" cell battery and the pushbutton switch. Experiment with the placement of the electromagnet about 3 cm from the compass. Press the pushbutton and quickly release. Experiment with pressing the pushbutton at different rates. Observe the action of the compass needle. Move the electromagnet while holding the pushbutton down. Observe the action of the compass needle. What is your explanation why the compass needle is attracted to one end of the electromagnet? ___________________________________________________ ________________________________________________________________ ________________________________________________________________ 16 Activity Sheet for Learning Experience #10 Name______________________

ELECTROMAGNETS AT WORK - BUZZER

Materials:

Electromagnet from Learning Experience #6 with 80 wraps of wire

Large homosote project board

2 cm round head wood screw with washer

#30 rubber band

3d iron nail

Sheet metal angle

Sheet metal strip

Pan head screw

Fahnestock clip

Screwdriver

Small square abrasive paper

30 cm piece #20 plastic insulated copper wire

Wire stripper

Directions:

1. Use the abrasive paper to sand the paint off the unbent end of the sheet

metal strip with a loop at one end.

2. Look at the drawing below. Locate the sheet metal strip with a loop at one

end in the position shown. Put the round head wood screw through the loop of the sheet metal strip and washer. Mark the location of the screw. Remove the screw and loop of sheet metal. Place a 3d iron nail on the mark and tip the iron nail a short distance. Replace the washer, sheet metal strip, and the screw. Screw the screw into the Homosote project board using the nail mark to position the screw. 17 Activity Sheet for Learning Experience #10 Page 2

3. At 2.5 cm from the end of the sheet metal strip, line up the sheet metal angle

so that both surfaces are touching. Attach the Fahnestock clip and sheet metal angle to the project board with the pan head screw. Turn the sheet metal angle as shown in the figure below.

4. At 2 cm from the end of the sheet metal strip, tap with the hammer the 3d box

nail into the Homosote project board as shown in the figure below. 18 Activity Sheet for Learning Experience #10 Page 3

5. Wrap #30 rubberband around banding wire and slip on to 3d as shown in the

figure below. Use the Electromagnet from Learning Experience #6 with 80 wraps of wire.

6. Connect the 4 "D" cells in series using the #82 rubberbands and Fahnestock

clips as battery holders.

7. Attach one wire from the top of the electromagnet to the "D" cell.

8. Attach a second wire from "D" cells to the Fahnestock clip on the metal

angle.

9. Attach a third wire from the electromagnet to the bolt between the project

board and the nut.

10. Hold the electromagnet close to, but not touching, the end of the banding

metal. It should buzz.

11. Caution: Do not leave buzzer connected for more than four minutes or the

"D" cells will go dead.

Note:

As you move the electromagnet toward the banding metal, you will notice sparks where the two metal pieces touch. These sparks will produce a coating which will have to be sanded off from time to time. If the buzzer doesn't work, check to see that the "D" cells are in series and all wires are connected and properly sanded at the contact points. 19 Activity Sheet for Learning Experience #10 Page 4 What is your explanation why the electromagnet works as it does? ___________ ________________________________________________________________ ________________________________________________________________ For a buzzer to work the _______________ attracts the buzzer arm and pulls it away from the metal angle. Now the carriage bolt is no longer a _____________ because the__________________ is no longer flowing. When the current is broken, the buzzer arm falls back against the_______________ . Instantly, a current is produced again, so the electromagnet works again until _______________________________________________________________ ________________________________________________________________. Sound is made because________________________________________ ________________________________________________________________. 20 Activity Sheet for Learning Experience #11 Name______________________

ELECTROMAGNETS AT WORK - ELECTRIC MOTOR

Materials:

"D" cell battery #82 rubber band

2 #2 paper clips

Rectangular magnet

Small square abrasive paper

1 meter piece #20 enameled copper wire

Emery board

1. Starting about 10 cm from the end of the wire, wrap the wire seven times

around the battery. Carefully remove the wire from the battery keeping it in a coil. Wrap the two tails around the coil so that the coil is held together and the two tails extend perpendicular to the coil. Cut both the wires, leaving 5 cm tails opposite each other. See illustration below: Note: Be sure to center the two tails on either side of the coil. Balance is important.

2. On one tail, use abrasive paper to completely remove the insulation from

the wire. Leave about half of a centimeter of insulation on the end and where the wire meets the coil. One the other tail, lay the coil down flat and remove the insulation from the top half of the wire only with a emery board. Again, leave about half of a centimeter of full insulation on the end and where the wire meets the coil.

3. Bend the two paper clips into the following shape with your pliers:

21
Activity Sheet for Learning Experience #11 Page 2

4. Use the rubberband to hold the larger loop ends of the paper clips to the

terminals of the "D" cell battery.

5. Stick the rectangular magnet on the side of the battery as shown.

6. Place the coil in the cradle formed by the right ends of the paper clips.

You may have to give it a gentle push to get it started, but it should begin to spin rapidly. If it does not spin, check to make sure all of the insulation has been removed from the wire ends. If it spins erratically, make sure that the tails on the coil are centered on the sides of the coil. Note that the motor is "in phase" only when it is held horizontally (as shown in the drawing).

7. Here is a diagram of the finished motor:

Magnet

22
Activity Sheet for Learning Experience #11 Page 3 What is your explanation why the motor works as it does? __________________ ________________________________________________________________ ___________ ________________________________________________________________ 23

Name: ______________________ Date: _________

Electromagnetism Student Assessment

Directions: Read the question carefully and answer based on your knowledge about electromagnetism. Circle the correct answer.

1.) The two magnets shown will.

A.) attract

B.) repel

C.) both attract and repel

2.) Which electromagnet will hold more paperclips?

A.) One with 10 coils

B.) One with 20 coils

C.) One with 30 coils

D.) All of them hold the same

3.) In the drawing, a magnet is held by a string. The magnet pushes away. What

end of the bar magnet is facing the magnet on a string?

A.) North

B.) South

C.) East

D.) West

4.) Which of the following metals can be found in a permanent magnet?

A.) Iron

B.) Cobalt

C.) Nickel

D.) All of these

5.) If I rub a paperclip with a magnet, it becomes a temporary magnet. Which of

the following is true about a temporary magnet?

A.) A temporary magnet only lasts a few days.

B.) A temporary magnet stops being a magnet when the magnetic fields is moved away. C.) Iron, nickel, and cobalt make up a temporary magnet.

D.) A temporary magnet has no north pole.

NS ? N 24
Electromagnetism Assessment Page 2

6.) Where does a compass point to on the Earth?

A.) The north pole

B.) The south pole

C.) Magnetic north

D.) Magnetic south

7.) How can you make an electromagnet stronger?

A.) Put in more voltage

B.) Wrap more coils around it

C.) Wrap less coils around it

D.) Numbers 1 and 2

8.) A machine for changing electrical energy to mechanical energy is a(n)

A.) Magnet

B.) Electromagnet

C.) Motor

D.) Compass

9.) Which of the following are true about magnets?

A.) They create a force called magnetism.

B.) The ends attract or repel each other.

C.) All magnets have a north and south pole.

D.) All of these are true about magnets.

10.) A permanent magnet can lose its magnetism if:

A.) It is heated up

B.) If you hit it with a hammer

C.) The domains are pushed out of line

D.) All of these

11.) Look at the drawings below and label which end of the magnet is nearest to

the compass.

Compass

Magnet

25
Electromagnetism Assessment Page 3

12.) Below we have a nail with wire wrapped around it. Explain what will happen

to the nail when we hook both wires to the battery. ________________________________________________________________ ________________________________________________________________

13.) Tell what the two following words mean.

Attract:

_______________________________________________________________

Repel:

________________________________________________________________

14.) A hanging magnet is attracted to a bar magnet as shown below. Explain

what would happen if I turned the bar magnet around. ________________________________________________________________ ________________________________________________________________

15.) Finish the following sentence...

If you move a magnet, (like in a motor) you make electricity. If you move electricity through a wire you make a ____________________.

16.) Explain what happens to the magnetism as I add more batteries in the

circuit. To explain it finish the sentence. The more batteries I add ...________________________________________

N S

N 26
Electromagnetism Assessment Page 4

17.) Magnetism is a force you cannot see. Tell one experiment you could do to

show that magnetism is really there even though you cannot see it. ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ 27

ELECTROMAGNETISM

STUDENT SELF-ASSESSMENT

Name:__________________________________ Date:___________________________________

1. What do you now know about electromagnetism that you didn't know before?

________________________________________________________________ ________________________________________________________________ ________________________________________________________________ What do you now know about magnets that you did not know before? ________________________________________________________________ ________________________________________________________________ ________________________________________________________________

2. How do you think you and your partner(s) worked together? Give some

examples. ________________________________________________________________ ________________________________________________________________

3. What learning experiences did you enjoy? Explain why did you liked them.

________________________________________________________________ ________________________________________________________________

4. Were there any learning experiences in the unit you didn't understand or that

confused you? Explain your answer. ________________________________________________________________ ________________________________________________________________

5. Take another look at your activity sheets and science notebook. Describe

how well you think you recorded your observations and ideas. ________________________________________________________________ ________________________________________________________________

6. How did your work in this unit affect your attitude toward science?

________________________________________________________________ ________________________________________________________________ 28

GLOSSARY

Attract: to draw or pull toward an object.

Armature: the movable parts of a motor consisting of coils or wire around a center core. Battery: a group of two or more cells connected together, usually in series, to furnish electrical current. Buzzer an electrical device that utilizes electromagnetism to generate vibrations or sounds Cell: a single unit used to generate or store electrical energy. Commonly called a battery. (See Battery) Coil: a number of turns of wire around a core to produce an electromagnetic effect. Compass: a device for determining directions by means of magnetic needle turning freely on a pivot and pointing to magnetic north. Electromagnet: a core of magnetic material surrounded by a coil of wire through which an electric current is passed to magnetize the core. Electromagnetism: magnetism developed by a current flow of electricity. Energy: the capacity for doing work and overcoming resistance. Force Field: an invisible field of energy surrounding an object such as a magnet or electromagnet. Magnet: any piece of iron, steel, or magnetite (lodestone) that has the property of attracting iron or steel. Magnetic: having the properties of a magnet. Magnetism: the property, quality, or state of being magnetic. Motor: a machine for converting electrical energy into mechanical energy. Pole: a region of concentrated magnetic energy. 29
Repel: to drive back or force away from an object. Sound: the vibrations in solids, liquid, or gases (air) that stimulate the nerves of the ear and produce the sensation of hearing.

System: a group of interacting objects.

Vibration: the rapid movement back and forth of a solid, liquid, or gas (air) that produces a sound.