inches (10 to 15 centimeters) across. It
has a lemon-yellow rind, or outside covering,
when it is ready to be picked. The
Grapes come in thousands of different varieties.
They range in color from yellow or
pale green to deep purple or black.
Grapefruit grow in clusters on trees with
shiny, green leaves.
BRITANNICA STUDENT ENCYCLOPEDIA Grapefruit 139
pulp, or soft inside, is light yellow, pink,
or red. The pulp has about 10 to 14
sections. Each section is surrounded by a
bitter skin and may include seeds.
Grapefruit are picked by hand or harvested
with a machine that shakes the
tree’s limbs. They are usually eaten fresh.
The juice is sold fresh, frozen, or
canned.
#More to explore
Citrus Fruit
Graph
Graphs are drawings that show mathematical
information with lines, shapes,
and colors. Graphs are also known as
charts. People use graphs to compare
amounts of things or other numbers.
Graphs are useful because they can be
easier to understand than numbers and
words alone.
There are many different kinds of
graphs. Some of the most common
kinds are circle graphs, bar graphs, and
line graphs.
Circle Graphs
Circle graphs are also called pie graphs
because they look like a pie divided into
wedges. Circle graphs show amounts of
different things as small or large sections
of the circle. For example, a circle graph
could show that three quarters of the
students in a classroom play video
games. The whole circle would represent
all the students. Three quarters of the
circle would be one color, to represent
the video-game players. The remaining
quarter of the circle would be another
color, to represent the students who do
not play.
Bar Graphs
A bar graph shows amounts as bars of
different sizes and, sometimes, of different
colors. Longer bars represent larger
numbers. For example, a bar graph
could show that one classroom had 30
students and another classroom had 15
students. Two bars would represent the
different classrooms. The bar for the
classroom with 30 students would be
twice as long as the bar for the classroom
with 15 students.
Line Graphs
A line graph uses dots connected by
lines to show how amounts change over
time. For example, a line graph could
show the highest temperature for each
month during one year. One side of the
graph would show a range of
temperatures. The bottom of the graph
140 Graph BRITANNICA STUDENT ENCYCLOPEDIA
would show the months. A dot over
each month would represent the highest
temperature for that month. Each dot
would line up with the correct
temperature on the side of the graph. A
line connecting the dots would show
how temperatures rose and fell over the
year.
#More to explore
Mathematics • Numbers and Number
Systems
Grass
Grasses are a family of plants with leaves
that usually look like blades. Most of
them also have hollow stems and many
branching roots. The green grass found
in yards, the grasses growing on open
land, grains, and bamboos all belong to
the grass family.
Where Grasses Grow
Grasses grow almost everywhere on
Earth because they can survive in many
different climates. Large areas of wild
grass are called grasslands.
Physical Features
Some grasses, such as bluegrass, are very
short. Others, such as giant bamboos,
grow as tall as 100 feet (30 meters).
Most grasses are soft and bendable, but
bamboos are harder, woody grasses.
In tropical regions grass leaves are broad.
Desert grasses have spiky leaves that help
keep moisture inside. The leaves of some
water grasses are waxy. The waxiness
protects them from the water.
Uses
Since ancient times people have eaten
the seeds of many grasses. These grasses,
called grains or cereals, include corn,
barley, millet, oats, rice, rye, sorghum,
and wheat. Livestock, or farm animals
that are raised by people, also eat grains.
Both livestock and wild animals graze on
wild grasses.
After people take the seeds from cereals,
the stalks of the plants are left. When
dried, these stalks are called straw. Farmers
cover the floors of barns with straw.
The green grass in Central Park helps New
York City look nice and is also good for the
environment.
BRITANNICA STUDENT ENCYCLOPEDIA Grass 141
People in some parts of the world use
straw to build roofs. People also weave
straw to make furniture, mats, baskets,
and hats.
People grow grass lawns because grass
makes a yard look green and attractive.
But grasses are also important to the
environment. Grass roots spread in all
directions. These roots prevent erosion,
or the loss of soil, by holding the soil in
place.
#More to explore
Bamboo • Grain • Grassland
Grasshopper
Grasshoppers are leaping insects that are
found all over the world. They live
mostly in forests or grasslands, but they
are also common in gardens. Their
brown or green coloring helps them
blend in with the plants and dirt around
them. Grasshoppers are closely related to
crickets.
Compared to many other insects, grasshoppers
are large. Some are more than 4
inches (11 centimeters) long. Grasshoppers
have long hind legs that are good
for jumping. They have antennas, or
feelers, on their heads that they use to
touch and smell. They also have special
