The Living Planet
Earth is the only planet on which life is known to exist. It is uniquely suited to life because it is warmed by the nearby sun, it is surrounded by a life-supporting atmosphere, it has a large supply of air and water, and there are plenty of minerals in its crust.
Earth in Space
- Earth is the third planet from the Sun.
- Earth is not quite a sphere. It is flattened slightly at the poles.
- The circumference of Earth at the equator is 40,075.02 km.
- The estimated area of Earth's surface is 510,065,600 square km.
- A true day (the time it takes for Earth to rotate on its axis) on Earth is 23 hours, 56 minutes, and 4.0996 seconds.
- It takes Earth 365 days, 5 hours, 48 minutes, and 46 seconds to orbit the Sun.
- Earth orbits the Sun at an average speed of 30 km per second.
- Earth experiences changing seasons because it orbits the Sun at an angle.
- Earth has one satellite, the Moon.
The Structure of the Earth
Earth is believed to consist of:
- an inner core about 2600 km in diameter made of solid iron and nickel
- an outer core about 2250 km thick made of molten iron and nickel
- a mantle of solid rock about 2900 km thick
- a crust about 6-70 km thick
The crust and the top layer of the mantle form about twelve major moving tectonic plates.
Earth is surrounded by an atmosphere made up of 78.09 percent nitrogen, 20.95 percent oxygen, 0.93 percent argon, and 0.03 percent carbon dioxide, as well as small amounts of neon, helium, krypton, hydrogen, xenon, ozone, and radon.
- Earth is about 4600 million years old.
- The closer to the center of Earth, the greater the temperature and the air pressure. At the center of the core, the estimated temperature is 4500 degrees Celsius.
- Life is believed to have begun on Earth about 4000 million years ago.
- Millions of years ago, Antarctica was a rainforest.
- About 71 percent of Earth's surface is covered by water.
- The Atlantic Ocean is growing about 2.5 cm wider each year. The Pacific Ocean is shrinking.
- About 400 earthquakes rock New Zealand every year.
- A rock from an active volcano might be about 1000 degrees Celsius. That's a bit too hot to handle!
- Australia has no active volcanoes.
- Seashells can be found high up on some mountains. The mountains were pushed up millions of years ago as Earth's crust folded and crumpled. They carried rocks and fossil shells up from the seabed.
- A person who explores and maps the inside of caves is called a spelunker.
- Stalactites hang from the ceiling of caves. Stalagmites rise up from cave floors.
- It takes about 1000 years to make 2.5 cm of soil.
- Sedimentary rocks cover more than two-thirds of Earth's surface.
- At present, people can drill only a few kilometers into Earth's crust.
- If we could dig all the way to China, we would have to start in Chile or Argentina. China and these two countries are antipodes — places opposite each other on the globe.
atmosphere: the mixture of gases surrounding Earth
bedrock: solid rock under the soil
continent: a large land mass
core: the innermost part of Earth's structure
crust: the outermost part of Earth's structure
earthquake: a shaking of Earth's surface caused by the movement of tectonic plates
erosion: when the rocks and soil of Earth's surface are loosened, worn away and moved
evaporation: the process of turning a liquid into vapor
geologist: a person who studies the structure, composition and history of Earth
igneous: rock formed from cool magma or lava
island: an area of land surrounded by water
mantle: the part of Earth's structure between the crust and the core
metamorphic: a rock altered by pressure, heat or chemically active fluids
mineral: a natural substance, such as a rock, that is not of animal or plant origin
ocean: a great mass of salt water
plain: a large, flat area of land
plate: large pieces of moving rock in Earth's crust
sedimentary: rocks composed of different layers deposited by water, wind or ice
soil: loose covering, of broken rocky material and decaying organic matter, over Earth's surface
valley: area of low land between two mountains
volcano: vent in earth's crust
Planet Earth: A Nonfiction Companion to the Original Magic School Bus Series by Joanna Cole, Bruce Degen, Carolyn Bracken, and Tom Jackson. This is a photographic, nonfiction companion book to The Magic School Bus Inside the Earth.
Rocks & Minerals by R. F. Symes. An Eyewitness Book full of stunning real-life photographs with captions to tell the story of Earth.
The Usborne Book of Earth Facts by Lynn Bresler. Packed with fascinating facts to capture the interest of students.
The Magic School Bus Inside the Earth by Joanna Cole and Bruce Degen. Ms. Frizzle takes her class on an excursion to the center of Earth. Zany illustrations and humorous fantasy are combined with a fantastic lesson in geology.
Earth Story by Eric Maddern. Explores the creation of Earth.
Beyond the Rolling River by Kate Andrew. The search for the tuning fork that controls Earth's weather.
The Iron Man by Ted Hughes. A giant Iron Man emerges from inside Earth.
Fantasia. Walt Disney. "Rite of Spring" section. The animation of this section shows the formation of Earth and the beginning of life.
If You Could See Earth. Britannica. (9 mins.) Satellite footage shows Earth, continents and oceans. The rotation of Earth and the forces of gravity are also explained.
Nature of Australia. ABC. (Two video set -- 150 min.) An account of how the island continent of Australia came to be the way it is.
Our Dynamic Earth. National Geographic. (23 mins.) More suitable for older students. Explains the theory of plate tectonics and includes live footage of earthquakes and volcanoes.
Adapted from "The Earth," Senior Topics. Published by Ashton Scholastic in Australia.