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INTRODUCTION:

Everything is spinning. Right now, you are spinning around on the Earth

at over 600 miles an hour. The Earth is spinning around the Sun at about

67,000 miles per hour. The entire Solar System is spinning around the

center of the Milky Way Galaxy at 558,000 miles per hour. And this is

nothing compared to the unbelievable speed that the electrons of every

atom in the universe are spinning around their nuclei. From the galactic

to the atomic scale,scientists have discovered everything is spinning.

The gyroscope is one of the most remarkable and widely recognized toys

in the world, yet few people realize it was originally developed by

scientists to study spin and demonstrate that the Earth is rotating. Close

observation of the astonishing behavior of gyroscopes led scientists to a

much better understanding of spin and the development of a vast number

of practical applications including the gyrocompass, flight instruments,the autopilot, gyroscopic stabilization and navigation for ships, airplanes,

space stations and satellites.

The hands-on lessons in this guide are designed for you and your students

to have fun while conducting experiments with gyroscopes and

discovering the amazing power of spin.


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CONTENT STANDARD K-4 5-8

Standard AScience as Inquiry

Abilities necessary to

do scientific inquiry

Understanding about

scientific inquiry

Abilities necessary to

do scientific inquiry

Understanding about

scientific inquiry

Standard BPhysical Science

Position and motion ofobjects

Light, heat, electricity

and magnetism

Motions and forces

Standard D

Earth and Space

Science

Objects in the sky

Changes in earth

and sky

Earth in the solar

system

Standard E

Science and

Technology

Abilities of technologicaldesign

Understanding aboutscience and technology

Abilities to distinguishbetweennatural objectsand objects made by

humans

Abilities oftechnological design

Understanding aboutscienceand technology

Standard G

History and Nature

of Science

Science as a

human endeavor

Science as a humanendeavor

Nature of science

History of Science

HOW DOES IT FIT WITH YOUR CURRICULUM REQUIREMENTS?This Teachers Guide addresses the following National Science Education Standards.

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BASIC EXPERIMENTAL PROCEDURE1. Ask Questions. (Why? How? How Long? etc.)2. EXPERIMENT: Look for answers. Try new things.3. OBSERVE CAREFULLY!4. Record data and your observations.5. Repeat your experiments to confirm your results.6. Summarize and analyze your results.7. Draw conclusions!

REMEMBER:Scientists often work in teams.Scientists share and discuss their results.

Lets Be Scientists

LESSON ONE:

The Power of Spin: The Gyroscopic Effect

Objectives: Students will conduct an experiment to discover the gyroscopic effect.

Students will learn about friction

Students will observe and record the results of their experiment.

Students will share and discuss their results with others.

Introduction:Invite your class to think of things that spin. Quickly elicit as many spinning

things as they can think of. You should be able to come up with quite a list.

Explain that scientists have discovered that spinning things have very special

behaviors that they are going to study and explore during the next five days.


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Lets Be ScientistsTell your class they are going to explore spin by becoming scientists. Ask

them for their ideas about what a scientist is and does. Discuss their ideas and

talk about how scientists seek to discover how and why things work by doing

experiments and making careful observations.

Give everyone a Lets Be a Scientist handout and go over the basic

procedures for experiments. Explain that scientists usually create their own

experiments to answer questions they have about the way things work. As

junior scientists, they will be conducting many fun experiments to explore the

power of spin.

Experiment #1: The Effect of Spin

Materials: (for each small group)

a CD (or old LPs can be used for more effect if you can find some)

a crayon

a piece of string

Procedure:

1. Divide the class into small groups and give everyone a handout.

2. Have students tie a crayon to one end of their string and slip the string

through the hole in the disk (CD or LP).3. Hold the end of the string and let the

disk hang free at the other end. Have

them swing it gently back and forth.

They will observe how the disk is

unstable and wobbles.

4. Now have the students give the disk a

good spin. As it is spinning, have them

swing the string again. They will observe

how the disk now stays level with the flooras it swings back and forth.

5. Have them repeat this experiment and this

time have them record their observations.

Have them write a description of what they

saw as well as draw pictures of their results

(i.e. not spinning and spinning). Make the

point that recording observations is one of


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Experiment #2: The Effects of Friction

Materials: a CD

a rubber band

a rulervarious surfaces

Procedure:

1. Tell students they are going to compare how well a CD slides across

different surfaces (i.e. the table top, the floor, a magazine, a notebook, wax

paper, aluminum foil, newspaper, sandpaper.) Set up different surface

stations around the class and have the groups rotate between them to save

on materials.

2. Emphasize that to do this scientifically, the force they use should be thesame on each slide. Before beginning, have them practice sliding the CD

on their desk by flicking it with their index finger. Have them do it a

number of times until it goes about the same distance each time. Have them

measure how far it goes with the ruler. (Measure from where the front edge

of the disk is to where it ends up.) Tell them to be careful to use the same

force every time.

the most important jobs of a scientist.

Another important part of being a scientist is sharing their results with other

scientists and comparing their data.

Discussion:

Your students have just demonstrated the gyroscopic effect or principle,

which very simply stated is thatany wheel or body rotating tends to stay in its

plane of rotation unless an outside force is applied. Repeat the experiment

in front of the class to reinforce this concept and lesson. Tell them the

gyroscopic principle is very useful. In the coming days, they are going to

conduct a series of experiments to explore and study this remarkable behavior

and learn how the gyroscopic principle is used in everything from toys to

airplanes to satellites.

Before exploring spin further, it is useful to introduce a very important force

working to slow spinning objects down. Ask students what caused the diskto stop spinning? This next experiment seeks to answer this question.


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3. Have the groups go to surface stations. Tell them to conduct at least three

trials on each surface and record the distance of each. Give them a couple

of minutes at each station and have them switch when it looks like

everyone has conducted at least three trials.

4. Have them find the average distance for each surface and determine which

surface was best for sliding.

Discussion:

Compare results by asking which surface was the best for sliding. Which was

the worst? Did the CD always stop? Why?

Discuss how two surfaces rubbing against each other create a force that slows

movement called friction. Have everyone rub their palms together quickly.

Ask what they feel. Explain that the heat is caused by friction. Friction is a

force that slows things down.

As they discovered in the experiment, friction depends on the materials thatare rubbing together. Some materials create a lot of friction. Have them predict

what will happen when they put a rubber band around the CD and try to slide

it. Have them try it. Tires are made from a similar material so they wont

slide. Some materials (called lubricants) are used to reduce friction, like oil or

soap. You can demonstrate this by having them wash their hands and feeling

the difference when they rub their soapy hands together.

Discuss how friction between the crayon and the disk slow down and stop the

spin. Point out that friction itself is not good or bad. It depends on what youare trying to do. Friction is not good when you are trying to go fast or keep

something moving, but very useful when you want to stop or slow something

down. A car is an excellent example of both cases. Friction is used when

braking to stop the car, but in the motor and many moving parts is not good

because it slows them down and causes wear so oil is used as a lubricant to

reduce friction.

Summary:

Scientists conduct experiments to discover how and why things are as they

are.

Spinning objects have interesting behaviors that need to be explored!

The gyroscopic principle saysany wheel or body rotating tends to stay in

its plane of rotation unless an outside force is applied.

Two surfaces rubbing against each other cause friction, a force that slows

down movement.


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LESSON ONE:The Power of Spin: The Gyroscopic Effect NAME: DATE:

Experiment #1: The Effect of Spin

Procedure:

1. Tie a crayon to one end of the string.

2. Slip the string through the hole in the CD.3. Hold the loose end of the string and let the CD hang

free at the other end.

4. Swing it gently back and forth. Observe the disk carefully.

5. Give the disk a good spin.

6. As it is spinning, swing the string back and forth

again. Observe the disk.

7. Repeat the experiment and record your observations below.

Draw pictures that show the difference between spinning

and not spinning.

Observations:

not spinning spinning


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LESSON TWO:

The Magnificent, Mysterious Gyroscope

Objectives: Students will conduct experiments with the gyroscopic effect.

Students will learn about gravity

Students will learn to spin a gyroscope. Students will learn about the axis of spin.

Materials: Pencils or Pens (Hexagonal are best.)CDs

Black electrical tape

Duncan Gyroscopes

Introduction:

Hold a pencil up over your head. Ask what will happen if you let go of it. Askwhy. Most of the students will be familiar with the concept of gravity, so

discuss what they know about it. Some points about gravity to discuss:

Gravity is a force of attraction between objects discovered by Isaac Newton.

The strength of the force is related to the size (mass) the larger (more

massive) the object, the stronger its gravity.

The Earth is the largest local object, so we notice its gravity most.

Earths gravity pulls things toward the center of the Earth.

The moon is held in orbit around the Earth. The moon has gravity, too, but it

is weaker because the moon is smaller than the Earth. Its gravity causes

tides on the Earth. The largest planet, Jupiter, has many moons (16 at last

official count and more being discovered all the time.) All of the planets in

our solar system are held in orbit around the Sun by its gravity. We feel the

Earths gravity more than the Suns, even though the Sun is bigger, because

the Sun is so far away.

Experiment #3: Balancing a Pencil on its Tip

Procedure:

1. Have students attempt to balance their pencils on their tip.

2. Ask if anyone can think of a way to balance their pencil on its tip.

3. Remind them of the last lesson and the gyroscopic effect as you hand out


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CDs and tape.

4. Have them cover the hole in the CD

with black electrical tape and poke the

pencil through the tape to create a

simple spin top. (They may need to

tape the pencil to stop it from slipping.)

5. Have them spin the pencil with the diskat the bottom, parallel to the table and

observe what happens.

Questions:

1. Could you balance the pencil on the tip

by itself?

2. What force caused it to fall?

3. Could you get it to stand with the disk

spinning? Why?

4. What happened when the disk stops spinning? Why?

5. Why did it stop spinning?

6. Does anyone know the name of the toy they just made?

7. How many have a toy top or have played with one?

Discussion:

Discuss how toy tops work. Review the gyroscopic principle:a spinning

wheel or body tends to stay in its plane of rotation unless an outside force is

applied. Talk about how the spinning tops they have made demonstrate this

principle. The gyroscopic effect counters the force of gravity and prevents thetop from falling while it is spinning. Talk about how the friction between the

table and the pencil tip slows the spinning top until the force of gravity is

stronger than the effect of spin and it falls over.

Spinning tops have fascinated people around the world for thousands of years.

It was not until the late 1700s and early 1800s that scientists started to pay

careful attention to spinning tops remarkable behavior and developed a very

useful new toy.

Introducing the GyroscopeTake out a gyroscope and ask if anyone knows what it is. Chances are that

someone will know what it is called. Write GYROSCOPE on the board.

Divide the word into gyro and scope. Ask if anyone knows what either of

these root words means. Most will know scope means to look or watch.

Elicit other words that use scope. [It comes from the Greek word scopein

which means to look.] Ask them what they think gyro might mean.


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Experiment #4: The Amazing Balance of a Gyroscope

Procedure:

1. Pass out gyroscopes to the

entire class. (Dont hand

out the string or Rip cords

yet.)

2. Have them attempt tobalance the gyroscope on

the pointed tip. [Note: One

tip is pointed and one is

more flat with string

groove.]

3. Ask how they think they

can get it to balance on the

tip.

4. Hand out the string and theGyro Basics handout. Let

them experiment and learn

how to wind and spin a

gyroscope. Allow them to

play and get accustomed to

spinning their gyroscopes.

5. While the gyroscope is

spinning on its tip have

them try to push it overwith their finger.

6. Demonstrate the amazing balance of a spinning gyroscope by having them

balance their spinning gyroscopes on:

Their finger

A pen or pencil tip (use the indented end)

On the string (This will take teamwork.)

Explain it means to turn or spin in a circle. [It comes from the Greek word

that means circle.]


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Questions:

1. Could you balance the

gyroscope on the tip when

it wasnt spinning?

2. Could you balance it when

it was spinning? Why?

3. What happened when the

gyroscope stopped

spinning? Why?

4. Could you push over the

gyroscope while it was

spinning?

5. Which spins longer, the

CD top or the gyroscope?

6. Spin gives the gyroscope

and top incredible stability.

Can you think of otherthings that use spin for

stabilization? (i.e. yo-yos,

Frisbees, footballs,

bullets)

Discussion: AXIS OF SPIN (Rotational Axis)

As students answer the questions, be sure to point out the remarkable ability to

balance is the result of the gyroscopic effect.

Discuss the different parts of a GYROSCOPE. Use the diagram to identify all

of them. Explain that the rotation of the disk (rotor) is centered around the

Axis of Spin (also called the Axis of Rotation, rotational axis). Point out that

the CD tops they made also have an axis of spin. Ask what it was. Discuss

how the axis of the top and gyroscope are different. Point out that there are

bearings where the axis meets the frame of the gyroscope. Ask what they are

for. The tip of spinning tops touch the surface they are spun on. What is the

result of two surfaces rubbing together? Gyroscopes have a frame that isolates

the rotor on an axis. The bearings reduce friction so the gyro spins longer.

(The frame still spins due to some friction in the bearings.) Note that axle

comes from the same root word as axis and discuss their similarity. Point out

that all wheels have an axis of spin. Ask if they know of anything else with an

axis of spin. (i.e. yo-yos, propeller, helicopter, Frisbee, a figure-skater, the

Earth)

AXIS

ROTOR

FRAME

BEARINGS


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Expand: The Earth is a Big Spinning TopUse a globe to show that the Earth is actually a big spinning top flying through

space. Give it a good spin and ask for a volunteer to point out the axis of spin.

Ask what the points at the end of the axis are called. The North and South

Poles are actually just opposite ends of the Earths axis of spin. The Earths

rotation is responsible for an enormous range of effects including global

weather patterns, winds and ocean currents, but most dramatic is the difference

between night and day.

Night and DayAsk how long it takes for the Earth to make one rotation on its axis. Discuss

how the Earth makes one complete rotation on its axis every 24 hours whichcauses night and day. Demonstrate by rotating the globe slowly

counterclockwise in front of a bright light. (This is most effective when you

turn out all of the lights and shut the curtains.) Point out the way that the

Earths rotation is what causes different areas to move into the light and then

out of it. Talk about how night is actually just caused by being in the Earths

shadow. Point to the lines of sunrise and sunset. Talk about the 24 time zones

and lines of longitude. Point out that it is the same time in the Northern and

Southern Hemisphere.

Calculation: How Fast Are You Spinning?There is an easy formula to figure out how fast you (and your students) are

spinning around the Earths axis. The circumference of the Earth is

approximately 25,000 miles. Since the Earth makes a complete rotation each

day, at the equator it is rotating at just over 1000 miles/hour. To calculate how

fast the earth is spinning where you are, multiply the speed at the equator by

the cosine of your latitude. Heres an example:


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If you are in New York City, your latitude is about 41.

The cosine of 41 is .755

1040 m/h x .755 = 785.2

miles/hour

Speed at equator cosine of latitude speed at your latitude

Find out the latitude of where you are and figure out how fast you are

spinning.

So if you are spinning so fast, why dont we notice? Explain that it is because

everything around us is also moving fast. It is like being in a car moving down

the highway. Since everything in the car is moving at the same speed, we only

notice that we are moving if we look out the window. We only notice that the

Earth is spinning by the changing position of the Sun and stars.

HistoryThe invention of the gyroscope is often

attributed to Leon Foucault, a French

scientist who gave it the name and

conducted many experiments using

gyroscopes. In 1852, he used a gyroscope

to demonstrate the Earth is rotating.

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LESSON TWO:The Magnificent, Mysterious Gyroscope NAME: DATE:

Time how long you can keep it spinning!

(To get the average, divide the total by the number of trials.)

TRIAL SECONDS

1.

2.

3.

TOTAL

AVERAGE

Label the different parts of the gyroscope!

TRY THESE TRICKS!

After you get the hang of spinning your gyro, balance your gyro on:

your finger

a pencil

a stringanother

spinning

gyro

(you will need

some help)

(hold the

bottom

frame until

the top gyro

is mounted

Experiment

1. Get your gyro spinning fast.

2. Put your finger on the top.

3. Try to push it over.

4. Observe what happens.

5. Repeat the experiment.

6. Record your observations.

Could you push it over? What happened when you pushed it?

Gyro Winding - The basics

Hold the gyroscope (often called a gyro)

in one hand. Put the end of the string

through the hole in the axis. Turn the

axis with the thumb of the hand holding

the gyro and continue to hold the stringwith your other hand to keep it snug while you wind. Leave about 2-3 inches of at the end to allow you to pull. Make

sure the string is tight around the axis. Hold the gyro by the outer frame and pull the string with one hard, smooth motion.

(Note: Depending on variation of spin top in your classroom, you may or may not have the version that includes the t-stick launching system (shown in some illustration


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LESSON THREE:

Gyroscopic Inertia and the Gyrocompass

Objectives: Students will learn about inertia

Students will learn the gyroscopic effect is also called gyroscopic inertia.

Students will observe and demonstrate the principle of Gyroscopic Inertia Students will learn how a gyroscope can be used as a compass

Materials: GyroscopesCDs

A magnetic compass

A bar magnet

Iron filings or Wooly Willy type toy

A piece of paper

Introduction:Ask for a volunteer. Have them come up and attempt to push your desk or a

heavy table. Point out that it remains at rest until a force acts on it. This is a

demonstration of Newtons First Law of Motion (often called the Law of

Inertia), which states that objects at rest will stay at rest, and objects in motion

will stay in motion unless acted upon by an unbalanced outside force. Inertia

is the resistance an object has to a change in motion. Stopping suddenly in a

car is a good example of inertia of moving objects and explains why we need

seatbelts.

Experiment #5: Gyroscopic Inertia

Materials: Duncan Gyroscopes

Procedure:1. Have the students balance their gyroscope on the ring of the frame that goes

around the rotor where it meets the frame that is in the plane of the axis.

(Where the two rings of the frame meet See the picture)

2. Have them grip the x that is formed at the intersection on top and give the

frame a spin with their hand. They will notice it spins easily.

3. Have them predict what would happen if the gyroscope were spinning.

4. Have them get the gyroscope spinning and do it again. Be careful not to


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touch the rotor. Remind them to repeat the experiment.

5. Have the students record their observations.

Questions:

1. What happened?

Discussion:

One of the important results of the gyroscopic

effect is that the axis of spin resists change; it

holds its orientation. This property makes

gyroscopes very useful. It is sometimes called

gyroscopic inertia, which is really just a more

descriptive name for the gyroscopic effect.

Inertia means a resistance to change. Recall

moving the desk or table. It resists being

moved, but if you apply enough force you can

move it.

Tell them this ability to hold their position has

made gyroscopes very useful. In the next experiment they are going to learn

how a gyroscope can be used as a compass.

Expand: The Gyrocompass

Ask: Which way is West? Why do you think so?

How about North? (Why?) South? (Why?) East? (Why?)

How can you be sure? Is there a way for us to check?

Magnetic Compasses

Take out a magnetic compass and ask if anyone knows what it is. What does acompass do? Ask if anyone knows how it works.

All magnets have magnetic fields surrounding them. This field is not uniform-

it is polar. Magnetic force is concentrated at the ends (poles). This can easily

be demonstrated and the fields shape and lines of force illustrated by putting a

bar magnet under a sheet of paper and covering it with iron filings. (A Wooly

Willy type toy is a neat and easy way to do this.)

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The Earth has a magnetic field. Scientists theorize that this magnetic field is

caused by the difference in spin between the Earths solid inner iron core and a

liquid iron shell surrounding it, which creates circulating electric currents

through the dynamo effect (like an electric generator.) Electric currents

create magnetic fields which are always in flux.

A compasss magnetic needle, when allowed to orient itself (usually by

balancing it on a point or in a liquid to create a nearly frictionless bearing),

aligns itself with this field and points to the magnetic poles.

The magnetic field of the

Earth can be pictured by

imagining a bar magnet inside

of the Earth, slightly tilted (by

11) from axis of spin. The

magnetic pole is currently

about 600 miles from the

North Pole. The exactlocations of the magnetic

poles vary from day to day

and year to year due to

movements and turbulence

within the Earths liquid iron

core. The magnetic north pole

has been moving every year

since it was discovered in

1831. Scientists have found that it is currently moving about 25 miles to thenorthwest every year.

Demonstration: Create a Compass

You can easily demonstrate this very practical use of a magnet by suspending

a bar magnet by its midpoint so it can swing freely. Watch how it orients itself

and holds its orientation. Check it with a real compass.

Ask: Who uses compasses? What do they use them for?

What are magnets attracted to?

What will happen if you move the compass near the magnet?

(Try it.)

What will happen if you put it next to a big piece of iron?

What problems might you have with a magnetic compass?

Explain that when they started to make ships out of iron (in the late 1800s),

they started to have trouble using magnetic compasses. You can demonstrate

the problem with a compass and a piece of iron.

S

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Experiment #6 : Make a Basic Gyrocompass

Make sure everyone has a CD, a handout and Gyroscope.

Procedure:

1. Have everyone orient the arrow on their handout so it is pointing north.

2. Have them place the CD on the handout.

3. Have them balance the gyroscope on the frame going around the rotor inthe hole of the CD so that the axis is parallel to the tabletop. (See picture

on handout.)

4. Have them orient the frame it is balancing on so it lines up with the arrow

pointing north.

5. Have them carefully turn the CD without touching the gyroscope with their

hands and observe what happens. Tell them not to turn it too quickly.

6. Have them predict what will happen when they repeat this experiment

when the gyroscope is spinning.

7. Have them repeat with the gyroscope spinning and record theirobservations. It is important that they keep the rotor perpendicular to the

tabletop.

Questions: 1. What does a compass do?

2. What happened when the gyroscope wasnt spinning?

3. What happened when the gyroscope was spinning?

4. What is needed for the gyroscope to keep pointing in the

same direction?

Discussion:

Explain that what they made is a very simplified demonstration of the primary

idea behind a gyrocompass. The CD represents their ship or airplane. When

the gyroscope is spinning, gyroscopic inertia will keep it pointing in the same

direction, no matter which direction their ship turns. Explain that this is just a

demonstration so that they can get the idea. Actual gyrocompasses are much

more complex.

The Gyrocompass

In the early 1900s a number of inventors realized that a gyroscopes ability to

keep pointing in the same direction could be used as a compass that would not

be affected by metal. The following is a simplified demonstration of the basic

concept behind a gyrocompass.


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Elmer Sperry: American InventorElmer Sperry is one of the most

prolific and important inventors to

have ever lived. He received over 360

patents during his life in a wide

variety of technologies including the

development of electrical light and

power industries, but it was his work

with gyroscopes that changed the

world. He began working withgyroscopes in 1896. In 1908, he

invented and introduced his first

north-seeking gyrocompass. Sperry

developed a wide range of inventions

utilizing gyroscopes, including the first autopilot (for ship and airplanes),

gyrostabilizers for ships and flight instruments for airplanes. He is

remembered as the Father of Modern Navigational Technology.

17

First, they have to keep the gyroscope spinning. Ask how they could keep it

spinning. Explain that they used an electric motor that keeps the rotor of a

gyrocompass spinning.

Second, they need a way to mount the

gyroscope to prevent outside forces from

acting on them. Since the ocean is often

rough, magnetic compasses had long

been mounted in a set of swiveling rings

called gimbals, so that they would

remain unaffected by the movement of

the ship at sea. The rings are connected

to each other by bearings. A gimbal-

mounted gyroscope keeps its orientation

no matter how the mounting is turned. It

is often called a universally mountedgyro. (See diagram)

Third, real gyrocompasses, when properly mounted, use the force of friction,

precession (see lesson 5) and the rotation of the Earth to orient themselves

to its rotational poles, making them north-seeking and especially useful

for navigation.

INNER

GIMBAL

ROTOR

OUTER

GIMBAL

Courtesy of the Hagley Museum and Library


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LESSON THREE:Gyroscopic Inertia and the Gyrocompass NAME: DATE:

Experiment #1: A Basic Gyrocompass

Procedure:

1. Orient this page so that the arrow is pointing to the North.2. Put the CD on the circle below. It represents your ship.

3. Balance the gyroscope on its rotor frame in the hole of the CD so that

it is perpendicular to the table top and the axis frame is parallel with it.

4. Orient the gyroscope so that the axis is pointing North.

(Note: gyro should not be spinning at this point)

5. Slowly turn the CD without touching the gyroscope.

(If the gyroscope falls over you are turning too fast.)

6. PREDICT: What will happen when the gyroscope is spinning?

7. Repeat the procedure with the gyroscope spinning.

(Important: Keep the rotor frame perpendicular to the table top.)

8. Record your observations.

Observations:

1. What happened when you turned the

CD and the gyro was not spinning?

2. What happened when the gyro was spinning?

3. Did the axis remain pointed in the same direction?

4. What happened as the gyro slowed down?

arrow should

point north

page 1 of


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LESSON THREE:Gyroscopic Inertia and the Gyrocompass NAME: DATE:

Gyroscopes: A History of Invention

Johann Gottlob Frederick von Bohnenbergeris credited with inventing the first known gyroscope inGermany in 1810. Instead of using a disk for a rotor, he used a

large metal ball. He was also an important developer of early

electrical devices and is also remembered for his invention of

the electroscope.

Leon Foucault

The invention of the gyroscope is often attributedto Leon Foucault, a French scientist who gave it

the name and conducted many experiments using

gyroscopes. In 1852, he used a gyroscope to

demonstrate the Earth is rotating. The year

before, he used a pendulum to prove the same.

He hypothesized that a gyroscope properly

mounted could be used as a compass.

Elmer Sperry: American InventorElmer Sperry is one of the most prolific and important

inventors to have ever lived. He received over 360 patents

during his life in a wide variety of technologies including

the development of electrical light and power industries, but

it was for his work with gyroscopes that he is remembered.

He began working with gyroscopes in 1896. In 1908, he

invented and introduced his first north-seeking gyrocom-

pass. Sperry developed a wide range of inventions utilizinggyroscopes, including the first autopilot and gyrostabilizers

for ships and airplanes. He and his son Lawrence devel-

oped gyroscopic flight instruments. He is often remembered

as the Father of Modern Navigational Technology.

page 2 o

Courtesy of the Hagley Museum and Library


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Lesson Four:

Gyroscopes and Flight

Objective: Students will see how gyroscopes stay rigid in space.

Students will learn pilots usually refer to gyroscopic inertia as rigidity in

space. Student will learn how gyroscopes are used in airplanes, space ships and

satellites.

Students will learn how seasons are due to the rigid angle of the Earth.

Introduction:Review that in the last lesson they learned one of the important uses of the

gyroscope. Ask if they remember what it was. Review the reason that it

worked. Discuss how not only sailors, but also pilots and astronauts put

gyroscopes to good use. Have them think and talk about the problems ofusing a magnetic compass in an airplane. Now think about a space ship. What

problems would astronauts face?

Experiment #7: Rigidity in Space

Explain that aviators usually refer to gyroscopic inertia as rigidity in space,which is just another way to describe the gyroscopic effect.

Materials: Duncan Gyroscopes (with string or pull cord)

Procedure:

1. Have the students hold their gyroscopes in their hand so that the pointed tip

of the axis is pointing away from them.

2. Have them toss it up in the air and observe any changes.

3. Now have them toss it up in the air, but this time flip it so it turns end over

end. Have them hold the frame at the end of the axis, flip it gently and

catch it. (It is best to do this over a table or a carpeted floor.)

4. Have them predict what will happen if they do the same thing while the

gyroscope is spinning.

5. Have them repeat the procedure with the gyroscope spinning. Have them

repeat it a number of times and record their observations.


24/3519

Questions:

1. What happened?

2. Could anyone flip it while it was spinning?

3. Why not?

Discussion:

The gyroscopic property of staying rigid in space is very useful to aviators

and astronauts. Since a spinning gyroscopes axis maintains a fixed direction,

it is an essential reference point in space. Give out the Lesson 4 handout and

discuss it.

Answers for Lesson 4 Handout:

1. The plane is flying North East or East by North East.

2. The plane is flying level.

3. The plane isnt turning.

4. Three gyros are needed to give a clear reference point in space. The axes are

arranged perpendicular to each other to form an XYZ reference point.5. The gyros on the space station spin at 6,600 rpm.

6. The cylinder at the bottom would spin to keep it stable.

Answers to Attitude Indicator: 2, 1, 3, 4

Expand: The Earths Axis and the Seasons

Like the axis of a spinning gyroscope, the Earths axis remains nearly rigid inspace as it orbits around the sun. The angle of the Earths axis is 23.4 from

perpendicular to the plane of its orbit around the sun ( the ecliptic.) Seasons

AUTUMN

WINTER SPRING

SUMMER

AUTUMNAL EQUINOX

FIRST DAY OF AUTUMN

IN NORTHERN HEMISPHERE

SUMMER SOLSTICE

FIRST DAY OF SUMMER


VERNAL EQUINOX

FIRST DAY OF SPRING


WINTER SOLSTICE

FIRST DAY OF WINTER



25/3520

are caused by the fixed angle of its axis. In the summer, you (and the pole of

your hemisphere) are tipped toward the Sun and in winter you are tipped away

from it.

Demonstrate with a globe by placing a lamp (with no shade) in the middle of

the table. Place the globe on the table so the North Pole is pointing away from

the Sun. This is the orientation of the Earths axis on the first day of winter.

Ask if anyone knows what day that is. You will notice how the globes stand

holds the axis at the correct angle of tilt. Point out that the South Pole is tilted

towards the sun, so it is the first day of summer in the Southern Hemisphere.

Point out the Artic Circle and explain on the first day of winter it is dark for 24

hours because of the angle of the tilt. What is the longitude of the Arctic

Circle? Can you explain why? Move the globe in orbit around the sun and

stop at a position where the poles do not point at or away from the Sun. Ask if

anyone can guess what day it is now. Explain that this is the first day of

spring (the equinox) when day and night are equal length. Continue the orbit

and stop on the first day of summer when the North Pole is pointing at theSun. Note how the sun does not set in the Arctic Circle on the first day of

summer, the longest day. Continue the orbit to the first day of Autumn.

Experiment #8: Applying Force to the Axis

Procedure:1. Have students spin their gyroscopes so that the axis is straight up and

down. Have them observe it until it stops spinning. Tell them to pay special

attention to what the axis of spin does as the gyroscope slows down. Have

them repeat this and record their observations.

2. Have them spin it again. This time, while it is spinning, have them push the

top of the axis with their finger and observe what happens.

Questions:

1. What happened to the gyroscope before it fell over?2. What did the axis of spin do?

3. What happened when they pushed the top of the axis?

4. What is causing the gyroscope to fall over?

Discussion:

Talk about how the axis wobbles around in a circle when an outside force

(torque) is applied . If the axis of a gyroscope is not vertical, the Earths


26/3521

gravity applies torque as it

tries to tip over the gyroscope

causing the axis to rotate in a

circle, tracing a cone. This

tilting or turning of the axis

caused by an outside force is

called precession. Notice thatas the gyroscope slows, the

precession gets faster and

faster until it finally falls over.

Tell them they will explore

precession in-depth in the

next lesson.

Expand:The Earths Axis isPrecessingEven though the Earths axis

remains basically rigid in

space, it precesses in a circle

like the axis of a gyroscope

because of the pull of the Sun

and the Moons gravity. It takes about 26,000 years for the axis to make one

complete circle. Currently, the axis points to Polaris, the North Star, but in

13,000 years, it will be pointing at another bright star, Vega. Because the axisis precessing in a circle, after another 13,000 years it will again be pointing at

Polaris. The precession of Earths axis was first noted by Hipparchus, a Greek,

in 130 B.C.

DIRECTION OF SPIN

DIRECTION OF PRECESSIONSPIN ANGULAR

MOMENTUM

GRAVITY


27/35

LESSON FOUR:Gyroscopes and Flight NAME: DATE:

Gyroscopes are very important to pilots. Their ability to remain rigid in space is used in differe

ways. Three of the most important instruments on a plane are gyroscopic.

Gyros in Flight

The Heading Indicator is a gyrocompass. Since magnetic

compasses are prone to error during turns, speed changesand turbulence, the Heading Indicator is the primary

directional instrument used on an airplane, but due to

error over time must be corrected against a compass.

1. What direction is the plane flying?

The Attitude Indicator is sometimes called the artificial

horizon. A gyros rotor holds the horizon bar stable during

flight and the plane rotates around it. The miniture airplane

wings on the case stay parallel with wings of the aircraft

and display the planes position in relation to the earths

horizon. It is probably the most important instrument

because it tells the pilot if the plane is tilted up, down ,

right or left (the planes attitude). This is the primary

instrument used when visibility is poor.

2. Is the plane climbing, diving or flying level?

The Turn Indicator is another gyro based instrument.

It indicates if the plane is banking and its rate of turn.

3. What direction is the plane turning?

Look at the Attitude Indicators. Wh

is the attitude of your aircraft? Writthe correct number next to each.

CHOICES:

1. Right Bank 2. Climbing

3. Diving 4. Left Bank

Gyros in Space

The Space Shuttle relys on gyroscopes for

orientation and navigation.

4. How many gyros do you think are neededto give a clear reference point in space?

The International Space Stationuses four 800 pound gyros to

maintain its orientation in space.

5. How many rotations per minute (RPM) do you think they are spinnin

Satellites often have internal gyroscopes to keep them pointed in the right direction.

Sometimes the entire satellite or a part of it spins to keep a fixed orientation.

6. What part of this satellite do you think spins?


28/3522

Lesson Five:Precession

Objective: Students will be introduced to and learn about the concept of precession.

Students will conduct a series of experiments to observe and demonstrate

precession and gyroscopic inertia.

Materials: Duncan Gyroscopes and string

Introduction:Review by asking what the gyroscopic principle says. Remind them it saysa

spinning wheel or body tends to stay in its plane of rotation unless an

outside force is applied. Today we are going to study what happens when you

apply an outside force to a spinning gyroscope with a series of experiments.

Experiment #9: Gyros respond to force at 90

Procedure:

1. Have the students spin their gyroscopes on the tip.

2. Have them hold the frame steady with their left hand so that they can

position the index finger of their right hand in the middle of the rotorframe. (See picture on handout).

3. Have them let go with their left hand and then push down with their finger

and observe what happens. Have them pay special attention to the direction

the axis falls.

4. Have them repeat the experiment, but now have them pay special attention

to how they wind the gyroscope so that they know the direction of rotation.

(If they wind the gyro in a clockwise direction, it will spin in a counter

clockwise direction when the string is pulled and vice versa.) Have them

repeat it with the gyroscope spinning in the other direction.

5. Have them repeat the experiment, but this time after they have done it once

have them flip the still spinning gyroscope over so that it is spinning on the

opposite end of the axis and do it again. Have them pay careful attention to

the direction that the frame falls. Have them repeat this a number of times.

6. Have them work in pairs. One student closes their eyes. The other spins the

gyroscope. The student with their eyes closed must determine the direction

of the spin using this method.


29/3523

Discussion:

They will observe that the axis will fall towards the table at 90 from their

finger (torque) in the direction of the spin. Explain that what they observed is

called precession. Basically, if an outside force (torque) is applied to a

spinning body, it will compensate by moving its axis at right angles (90) to

the direction of the force (torque). This behavior of gyroscopes leads to some

very surprising results as the next two experiments will demonstrate.

Experiment #10- The Conservation of Angular Momentum

Procedure:

1. Have the students try to balance their gyroscope on the ring of the frame

that goes around the rotor. The frame around the axis should be parallel

with the table. They should be able to do it but not that easily.

2. Have them push down on the end of the axis and observe what happens.3. Have them repeat the experiment but push down on the opposite end.

4. Have them predict what would happen if the gyroscope were spinning.

5. Have them repeat the experiment with the gyroscope spinning. Tell them to

pay special attention to the direction of spin.

6. Have them push down on one end while it is still spinning. Then, while it is

still spinning push down on the other end of the axis.

7. Have the students record their observations.

Questions:1. Could you push down the end of the axis when it was spinning?

2. What happened?

3. What happened when they pushed on

the other end?

4. Could you feel the gyroscopic inertia?

Talk about how the gyroscopic inertia

felt as they pushed down on the end of

the axis.

Discussion:

All moving objects have momentum.

Angular Momentum is the momentum of

a spinning object. The direction of its

force is parallel to the axis of spin.

Scientists explain the gyroscopic effect

with the principle of the Conservation of DIRECTION OF ANGULAR MOMENTUM


30/3524

Angular Momentum which says that this momentum must stay constant

(you cant destroy momentum).When an outside force (torque) is applied, the

gyro reacts by transferring its momentum perpendicular (at 90) to the

applied force causing it to rotate. This is called precession. The axis stays

horizontal, but the gyroscope responds by rotating at 90 around the applied

force.

Experiment #11: Suspending a spinning gyroscope

Procedure:

1. Have students hold the gyro so that the axis

is horizontal and have them thread the string

through the opening between the axis andthe frame. Then, have them lift the string up

around the axis and grab both ends of the

string. (See the pictures.) Have them practice

threading the string like this a couple of

times while the gyro is not spinning.

2. Have them predict what will happen when

they let go of the gyro.

3. Have them predict what it will do when the

gyro is spinning.

4. Have them find out.

Questions:

1. What happened when they let go of the gyro when it wasnt spinning?

2. What happened when it was spinning? Did anyone

predict it?

3. What force is acting on the gyro when they let go?

Discussion:

This is one of the most impressive demonstrations ofprecession. Most people expect the end of the gyro to

fall due to gravity and are very surprised when it

begins to rotate around the string. Discuss how the

gyroscope resists the external force of gravity

pulling down on the axis by precessing,

rotating the axis at 90 to the force of gravity.


31/35

Try this: Get the gyro spinning, turn it so the axis is horizontal and put the tip

on your finger. What do you think it will do?

Expand: The Bicycle Wheel Gyro

An exciting way to culminate your Week of the Gyro! is to bring out the

bicycle wheel gyro. This is a common piece of equipment in many highschool science departments. If you dont have one available to you, it is

possible to make one or get one from almost any scientific equipment supplier.

Basically, it is just a bicycle wheel with handles extending from its axle.

There are many websites that show how to make and use one. Some even have

movie clips of them in action. There are a number of different experiments

usually performed with a bicycle wheel gyro.

1. Experiment #11 can be really reinforced if you demonstrated precession

with the bicycle wheel gyro by suspending it by one of the handles when it

is spinning. There are a number of good videos of this online.

2. Demonstrate the Conservation of Angular Momentum. This famous

demonstration is always a crowd pleaser and a good way to wind up the

week. With young kids it is very important to observe safety (if they are

allowed to try it.)

A. Sit in a chair that swivels (easily) and hold the wheel vertically between

both hands. Have someone spin the wheel very fast.

B. Twist the axis from horizontal to the vertical (so the wheel is horizontal)and the chair will start to spin. Twist it in the other direction and the

chair will spin in the other direction.

NOTE: If you are going to use a bicycle wheel gyro, it is recommended that

you research their use online. There are many good sites with excellent

instructions.

Congratulations!

Upon completion of these lessons your students willhave a new understanding of the amazing power of spin.

25

Answers to Review Quiz:

1. gyroscopic principle, 2. friction, 3. gravity, 4. rotation, 5. inertia, 6. axis of spin,

7. precession, 8. magnetic field, 9. gyrocompass,

10. (clockwise from upperleft) autumn/fall, summer, spring, winter (see page 19)


32/35

LESSON FIVE:Precession NAME: DATE:

Experiment: How Gyros Respond to Outside Force

Procedure:1. Get your gyro spinning and put it on the tip.2. Hold the frame steady with your left hand. Put the index finger of

your right hand in the middle of the rotor frame.3. Let go with your left hand and push down with your finger and

observe what happens. Pay special attention to the axis. Do itwhen it is not spinning and notice the difference.

4. Repeat the experiment. This time pay special attention to howyou wind the gyroscope so that you know the direction of rota-tion. (If you wind the gyro in a clockwise direction, it will spin in a counter clockwise direction when the strinis pulled and vice versa.)

5. Repeat the experiment with the gyroscope spinning in the other direction.6. Repeat the experiment, but this time after you have done it once, while the gyroscope is still spinning, flip it

over and do it again.7. Record your observations.

Observations:

1. What happened to the axis when you pushed down with your finger? Does it do this every time?

2. What is the relationship between the direction the axis moves and the direction of the spin?

3. What happened when you flipped the gyro over and pushed down? (Step 6) What conclusion can you drawfrom this?

Experiment: The Conservation of Angular Momentum

Procedure:1. Balance your gyroscope on the ring of the frame that goes around the rotor. The

frame around the axis should be parallel with the table.2. Push down on the end of the axis and observe what happens.3. Predict what will happen when the gyroscope is spinning.

4. Repeat the experiment with the gyroscope spinning. Pay special attention to thedirection of spin.

5. Push down on one end while it is still spinning. Then, while it is still spinning push down on the other end ofthe axis.

6. Record your observations.Observations:1. Could you push down the end of the axis when it was spinning? What happened?

2. What happened when you pushed on the other end?

3. Could you feel the gyroscopic inertia when you pushed down?

page 1 of


33/35

LESSON FIVE:Precession

page 2 of

(continued)NAME:

Experiment: Suspending a Spinning Gyroscope

Procedure:1. Hold the gyro so the axis is horizontal and put the string through

the opening between it and the frame. Lift the string up aroundthe axis. Practice this a couple of times while the gyro is not

spinning. (See the pictures.)2. Predict what will happen when you let go of the gyro. Hang on

to both ends of the string and find out. Record the result.

3. Predict what the gyro will do when it is spinning.

4. Get the gyro spinning as fast as you can, thread the string aroundthe axis as you did in step 1, hold on to both ends of the stringand let go of the gyro. Be careful not to touch the rotor while youare threading the string. Record you observations.

Observations:1. What happened when you let go of the gyro when it wasnt

spinning?

2. What happened when it was spinning?

3. What forces are acting on the gyro when you let go?


34/35

REVIEW QUIZ:The Amazing Power of Spin NAME: DATE:

Fill in the blanks with words from this vocabulary list.

axis of spin gyroscopic principle magnetic field

friction gyrocompass precession

gravity inertia rotation

1. The says a rotating body tends to stay in its plane of rotat

unless an outside force is applied.

2. is caused by two surfaces rubbing together. It is a force that slows things

down.

3. Earths pulls things towards the center of the Earth.

4. Night and day are caused by the of the Earth.

5. is the result of an outside force being applied to a spinning object.

6. The rotation of an object is centered around its .

7. means resistance to change.

8. Scientists think Earths is caused by a difference in spin betwe

the Earths solid iron core and the liquid iron shell surrounding it.

9. A utilizes a gyroscopes ability to keep pointing in the same direction.

10. Label the seasons in the diagram below.


35/35

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