Earth science encompasses a whole lot more than just the land on which we stand. Your child will find earth science includes the depths of the ocean, the air we breathe, and the weather we both enjoy and bemoan. Use this guide to help steer your young geologist, meteorologist, or oceanographer along the craggy coast of science.
Because it's all around us, earth science is one of the easiest subjects to incorporate into a stroll along the bank of a river or a morning making mud pies out of topsoil in the backyard. Get a grasp on the major topics that your child will learn when studying earth science in school:
What Is Earth?
No one knows for sure, but scientists believe that over 4.5 billion years ago, the earth was born from a cloud of dust particles and metals. As the solid planet formed, it separated into three distinct layers: the crust, the mantle, and the core.
- The crust making up the outer layer of the planet is not solid. Instead, about 10 tectonic plates fit together to cover the mantle. Large cracks in the earth's surface are called faults. The surface of the earth's crust is always moving, but it's almost never noticeable to us. The exception is when the plates move against each other violently, creating an earthquake.
- The mantle, or middle layer, is hot enough in some places to melt solid rock. The melted rock substance is also known as magma.
- The core deep inside our planet consists of an outer layer made of magma and a solid inner center.
Rocks, Air, and Water: Our Planet's Building Blocks
Rocks
From simple observation, your child will learn a lot about the properties of rocks. Smooth marble looks and feels different than shale, which usually has a sandy texture with obvious layers. Rocks have different characteristics because of how they are formed and what minerals — or solid chemical substances — they contain. Granite and other igneous rocks are made of cooled and hardened magma.
- Sedimentary rocks, such as sandstone, are formed when layers of minerals, decayed plants and animals, and tiny grains of sand are squeezed together under great pressure. Because sediment settles to the bottom of water, these rocks are often found near rivers.
- Metamorphic rocks start out as either igneous or sedimentary, but are transformed into something new by extreme forces like high temperature or strong pressure. Marble is a metamorphic rock.
- Soil is formed when small pieces of rock and minerals combine with organic, or once living, particles. Topsoil is the rich dirt where plants like to grow. Below that lies subsoil, which has fewer nutrients. Both layers rest on a solid layer of bedrock.
Air
Take a deep breath; the atmosphere is a large bubble of gases surrounding the earth. From near to far, the first two layers of the atmosphere are the troposphere, which contains the air we breathe and clouds, and the stratosphere, which includes the ozone layer.
- Air is a made up of a combination of gases. Heated air rises, then cools and falls. This creates wind. When a mass of warm air and a mass of cold air first meet, they don't mix immediately. The edge between them is known as a front.
- Clouds are made up of water droplets that have attached to dust or smoke in the air. When clouds are saturated with moisture too heavy to be held up, they release precipitation in the form of rain, snow, sleet, or hail.
- A barometer is a tool to measure air pressure or the weight of the atmosphere at any given point. Rising air pressure usually indicates weather will be fair. Falling air pressure may mean a storm is approaching.
Water
From splashing at the preschool water table to middle-school experiments with test tubes and Bunsen burners, your child will learn about water her whole school life. It's understandably an important topic since oceans and seas cover almost three-quarters of the earth's surface. A sea is a slightly smaller, saltwater body and is usually a part of its big sibling, the ocean. The four oceans are: the Atlantic, Pacific, Indian, and Arctic.
The rise and fall of waters in the oceans and seas — known as tides — are caused by the pull of the moon's gravity on Earth. High tide and low tide occur twice daily.
Other large bodies of water include lakes, which are surrounded by land and are usually freshwater, and rivers that begin at a source and flow between banks of earth to a mouth, where they empty into a larger area, such as an ocean.
Energy: The Natural Source of Power
Energy means "the ability to do work." Your child will undoubtedly learn that energy can be changed from one form to another, but it cannot be created or destroyed. In order for power to be harnessed, energy is collected from different sources and put toward doing work. For instance, the energy in heat can boil water that produces steam to move a generator that provides power to a machine.
Energy Sources
The element carbon is present in all living things. Scientists think the carbon-based gas, oil, and coal found underground comes from the remains of carbon-based animals and plants from millions of years ago. The remains of living things are known as fossils, hence the term fossil fuels.
When fossil fuels are burned, carbon dioxide is produced, which contributes to global warming. The gases produced from burning oil and coal combine with moisture in clouds and lead to acid rain. Fossil fuels exist in limited quantities, making it important to investigate other means of harnessing energy including these examples:
- Hydroelectricity is power produced by the energy of falling water.
- The energy released from atomic fission, or breaking apart an atom, can produce the efficient energy of a nuclear power plant or the destructive power of an atom bomb.
- The harnessed energy of windmills provides wind energy.
- Solar energy gathers and uses light from the sun.
- Geothermal energy refers to electricity produced from collecting the extreme heat deep within the earth.