#More to explore
Algae • Bog • Lichen • Plant
Moth
#see Butterfly and Moth.
Mother Goose
Some people think that many children’s
songs and nursery rhymes were written
by someone called Mother Goose. She is
Moss covers a forest floor. often pictured as an elderly woman
190 Moss BRITANNICA STUDENT ENCYCLOPEDIA
riding on the back of a flying goose. But
scholars do not know if Mother Goose
ever existed.
According to one story Mother Goose
was a woman named Elizabeth Goose.
She lived in Boston, Massachusetts, in
the 1600s. Some people believe that
rhymes she made up for her grandchildren
survived as the Mother Goose tales
familiar today. But no one has found
any proof that she wrote the stories.
In France a book of fairy tales published
in 1697 was called Tales of Mother Goose.
In the 1760s John Newbery of England
published the first edition of Mother
Goose rhymes as they are now known.
He probably took the name Mother
Goose from the French book. Newbery’s
book was published in the United States
in about 1785. Generations of American
children have learned the rhymes, such
as “Humpty Dumpty” and “Little Miss
Muffett.”
#More to explore
Nursery Rhyme
Mother Teresa
#see Teresa, Mother.
Motion
When we say that something is in
motion, we usually mean that it is moving.
But motion has a special meaning
in science. In science, motion is a
change in position compared to a place
or an object that is not moving. The
place or object that is not moving is
called the frame of reference.
Motion is a kind of puzzle because every
object in the universe is in motion. This
means that no frame of reference is correct
in every situation. For example, a
car is in motion when the ground is the
“There Was an Old Woman Who Lived in
a Shoe” is a popular nursery rhyme from
Mother Goose.
A boy on a swing is in motion.
BRITANNICA STUDENT ENCYCLOPEDIA Motion 191
frame of reference. In this situation, we
think of the ground as not moving. But
the ground, a part of Earth, is in motion
when the sun is used as the frame of
reference. This is because Earth travels
around the sun.
Describing Motion
An object in motion can be described by
its speed and its velocity. The speed of a
moving object is a measure of how fast it
is moving. Speed is equal to the distance
the object travels divided by the time it
takes to travel that distance. For
example, a car that travels 30 miles in
one hour has a speed of 30 miles per
hour. Velocity describes how fast an
object is moving in a certain direction.
Newton’s Laws of Motion
In the 1680s the English scientist Isaac
Newton came up with three laws that
describe motion. In his first law, Newton
explained that the motion of an
object will not change unless a force
pushes or pulls on the object. In his second
law, Newton showed that a strong
force makes an object move faster than a
weak force acting on the same object. In
Newton’s third law, he said that whenever
a force pushes an object, the object
pushes back with an equal and opposite
force.
#More to explore
Force • Newton, Isaac
Motorcycle
A motorcycle is a two-wheeled vehicle
with an engine. Motorcycles are bigger,
heavier, and much faster than bicycles,
but they have many similar parts. Like
bicycles, motorcycles are often called
bikes.
Motorcycles are a common form of
transportation throughout the world.
People also ride motorcycles in races or
just for fun.
Motorcycle Design
Like an automobile, a motorcycle usually
has an internal-combustion engine
powered by gasoline. The body of the
motorcycle, called the frame, is usually
made of steel. Handlebars and a cushioned
seat sit on top of the frame. The
two tires are attached to the front and
the back of the frame. They are much
like car tires, but smaller.
Brakes, a headlight, a taillight, turn signals,
and a horn are important safety
features on every motorcycle. Some
motorcycles have crash bars, which keep
the motorcycle from hitting the ground
if it falls over. A motorcycle might also
have a windshield for protection.
Many motorcyclists wear protective gear,
such as a helmet.
192 Motorcycle BRITANNICA STUDENT ENCYCLOPEDIA
Motorcycles are designed for different
purposes. Street bikes, touring bikes,
and small mopeds and scooters are built
mainly for riding on paved roadways.
Touring bikes are specially equipped for
long-distance highway travel. Lightweight
dirt bikes, racing bikes, trail
bikes, and minibikes are meant for offroad
biking.
Using a Motorcycle
Motorcycle riders need their hands and
their feet to drive their vehicles. The
driver turns on the engine using a key.
Once the engine is on, the driver uses
controls on the handlebars and foot pedals
to drive. A twist of a handgrip controls
the speed of the vehicle. The
handlebars also have a lever to control
the front brakes. Pedals control the rear
brakes.
Motorcyclists must obey the rules of the
road and follow other laws related to
motorcycles. Many countries require a
special driver’s license for operating
motorcycles. In some places every
motorcyclist must wear a helmet.
History
Many inventors in the 1800s tried to
put engines on bicycles. These first
motorcycles had steam-powered engines.
