What Is The Solar System? The
Solar System formed around 4.6 billion years ago. The
Solar System is full of planets, moons, asteroids, comets, minor planets, and
many other exciting objects.
The
Solar System is made up of all the planets that orbit our Sun. Everything in
the Solar System orbits or revolves around the Sun. It is
true that there are only eight planets. However, the Solar System is made up of
over 100 worlds that are every bit as fascinating. Some of these minor planets,
and moons are actually larger than the planet Mercury!
The
inner planets (also known as terrestrial planets) are smaller and made mostly
of rock and metal. The
outer planets (also known as gas giants) are much larger and made mostly of hydrogen,
helium and other gases.
THE EARTH’S ROTATION AND ORBIT
The Earth rotates on its axis. The Earth’s axis is tilted.
This rotation is why we have day and night.
It takes
twenty-four hours to complete one rotation.
The Sun shines on one
half of the Earth, so it’s day on the half of the Earth that
faces the Sun and it’s nighton the half of the Earth that faces away from the
Sun.
When the Earth orbits the Sun, one hemisphere receives more light and
heat than the other. This is whythere are different climates and seasons on Earth.
THE EARTH’S MOON.
The moon is the Earth’s only natural satellite.
The moon takes about twenty-eight days to orbit the Earth and it rotates on its axis at the same time.
The bright part of the moon is the part that the Sun is shining on.
The moon reflects this
light from the Sun and this is what we see
from the Earth.
The moon looks as if it’s changing shape and we call these shapes the
phases of the moon.
What is climate? Climate is the average weather
usually taken over a 30-year time period for a particular region and time
period. Climate is not the same as weather, but rather, it is the average
pattern of weather for a particular region. Weather describes the short-term
state of the atmosphere.
Climate is a country’s
normal weather over a long period of time. By climate we mean a
country’s rain and sunshine, winds, storms and everything else that makes up the
weather.
The weather changes from
day to day and even from hour to hour. It can be sunny in the
morning and cold and wet in the afternoon. The climate changes very
slowly over thousands of years.
We know that the Equator
means heat and the Arctic means cold. Climates are also affected by
how close a country is to the sea and by how high a country is.
What is
weather? The weather is just the state of the atmosphere at any time,
including things such as temperature, precipitation, air pressure and cloud
cover. Daily changes in the weather are due to winds and storms. Seasonal
changes are due to the Earth revolving around the
sun.
There is one basic reason we have weather, and that is the sun.
Weather systems start because the sun’s energy heats up some parts of
Earth more than others. Most of the time the sun shines most directly on
the middle of Earth, with less heating at the north and south poles.
Earth is tilted on its axis at exactly the right angle to have seasons,
with different parts of Earth being heated more or less during
different times of the year. Land heats up faster than water, wetting up
temperature differences between oceans and continents. This unequal
heating creates variations in temperature and air pressure, winds, and
ocean currents.
What causes weather? Because the Earth
is round and not flat, the Sun's rays don't fall evenly on the land and oceans.
The Sun shines more directly near the equator bringing these areas more warmth.
However, the polar regions are at such an angle to the Sun that they get little
or no sunlight during the winter, causing colder temperatures. These
differences in temperature create a restless movement of air and water in great
swirling currents to distribute heat energy from the Sun across the planet.
When air in one region is warmer than the surrounding air, it becomes less
dense and begins to rise, drawing more air in underneath. Elsewhere, cooler
denser air sinks, pushing air outward to flow along the surface and complete
the cycle.
SEASONS. We divide up the year into four seasons: spring, summer, autumn, and
winter. Each season lasts 3 months with summer being the warmest season,
winter being the coldest, and spring and autumn lying in between.
The seasons have a lot of impact on what happens on the earth. In the
spring, animals are born and plants come back to life. Summer is hot and
is when kids are usually out of school and we take vacations to the
beach. Often crops are harvested at the end of the summer. In autumn the
leaves change colors and fall off the trees and school starts again.
Winter is cold and it snows in many places. Some animals, like bears,
hibernate in the winter while other animals, like birds, migrate to
warmer climates. Seasons are caused because of the Earth's changing relationship to the
Sun. The Earth travels around the Sun, called an orbit, once a year or
every 365 days. As the Earth orbits the Sun the amount of sunlight each
place on the planet gets every day changes slightly. This change causes
the seasons.
