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10 Energy Forms

By Tamara Hyde
Last updated about 3 years ago
13 Questions
What is energy? You probably know that we need energy to drive our cars, heat and cool our homes, and run our computers. In fact, if you set out to make a list of everything you used energy for in one day, you could probably fill several pages. You would even need energy to make the list!

In this lesson, you will learn what energy is and examine several common sources of energy.

OBJECTIVES

  • Identify the two types of energy.
  • Distinguish between renewable and non-renewable sources of energy.
  • Describe several sources of energy.

VOCABULARY

wind energy - energy created by the Sun's uneven heating of the Earth's surface
biomass - a material made from plants or animals
chemical energy - energy derived from chemical bonding between atoms
elastic potential energy - stored energy from the shape of an object
electrical energy - a secondary source of energy derived from changes in motion
electromagnetic energy - form of energy that travels through space in waves
energy - a property capable of causing changes in matter
fossil fuel - a carbon-based fuel derived from living matter that existed in prehistoric times
geothermal energy - energy obtained from steam or water heated below the earth's surface by natural sources of heat
gravitational potential energy - stored energy due to height from a reference point
hydro-energy - energy obtained by directing moving water over blades or turbines
kinetic energy - the energy of a moving object
mechanical energy - the sum of the kinetic and potential energy of an object
nonrenewable resource - an energy resource that cannot be replenished in a short period of time
nuclear energy - energy released during the fission of an atomic nucleus or the fusion of two atomic nuclei
potential energy - stored energy
renewable resource - an energy resource that can be replenished in a short period of time
solar energy - the use of the Sun's radiation to directly heat living or working spaces or to produce electricity
thermal energy - the kinetic and potential energy of the microscopic particles of an object
tidal energy - energy derived from the movement of oceanic water masses
wave energy - energy obtained from the movement of wind-driven water waves
Energy exists as one of two types—kinetic energy or potential energy. Kinetic energy is the energy of a moving object. Potential energy is the energy stored in an object. Both kinetic and potential energy can be obtained from a multitude of different sources.

Energy can be derived from both renewable and nonrenewable sources. A nonrenewable resource is one that cannot be replenished (made again) in a short period of time. All fossil fuels, such as natural gas, oil, and coal, are considered nonrenewable. On the other hand, many of the renewable fuels used in the past are gaining new popularity today. Renewable sources of energy, such as solar energy, can be readily replenished.

Energy is known by the changes it causes. You can hear the roar of an avalanche or see the movement of a wind mill. Scientifically, work is done when a force moves an object through a distance. Energy is the ability to do work. So whether is is the air molecules being moved by a vibration causing sound or the wind pushing the arms of a windmill, work is being done. Essentially, work is the transfer of energy.
1.

Select all energy sources that are considered renewable.

RENEWABLE ENERGY DERIVED FROM THE SUN
Biomass. One early source of energy was biomass, a material made from plants or animals. For example, plants convert the energy of the Sun into chemical energy using the process of photosynthesis. This energy is then stored in the plant. The stored energy is called biomass. Throughout much of history, people have used the biomass in wood to heat living areas and cook food.

Today, many different types of biomass are being used to release energy. Everything from garbage to yard waste to cherry pits are being burned as fuel. When used in this way, the chemical energy in the material is released mainly as heat energy. This energy is passed into water to produce steam. The steam is then used in the process of creating electricity. Many plant crops, such as corn and sugar cane, can also be fermented, producing valuable alcohols which can then be used for fuel. For example, the chemical energy stored in corn is used to produce ethanol fuel, an alternative to gasoline.

Although biomass is considered a renewable resource, excessive use of biomass can deplete resources in certain areas. For example, over-harvesting wood can lead to deforestation.
2.

Which is not a source of biomass energy?

Solar energy. Like the energy stored in biomass, most energy is ultimately derived from the Sun. However, the term solar energy usually applies to the Sun's radiation which is harnessed to directly heat living or working spaces or to produce electricity. Solar energy is a virtually limitless resource. In fact, the amount of solar energy that reaches the earth in one hour is more than the total amount of energy that humans use in one year. While solar energy is plentiful and can be captured, storing and transporting the energy poses problems.

Storage is a critical point because the input from the Sun is not constant. On average, half of every 24-hour period is spent in darkness. In addition, clouds may interrupt the strength of the solar input during daytime hours. At the present time, most captured energy is used almost immediately and close to the collection point. Examples include solar ovens to cook food and energy collectors to heat water, swimming pools, and houses. Some road-side collectors are used to provide power to traffic signs. Interest in use of solar energy is growing, but at present, it cannot economically compete with fossil fuels in producing energy for electrical use.

Think about it!
Solar energy collectors are more likely to be found in areas where the Sun is more directly overhead (the tropics) and where availability of fossil fuels is low.
3.

Select ALL listed problems with solar energy:

Wind energy. The uneven heating of the Earth's surface causes air masses to move about in the atmosphere. This wind energy has long been used to push the wheels or paddles of windmills. Early windmills (such as those in Holland) included a system of gears that turned when the main blades caught the wind, causing other parts of the apparatus to rotate (such as a stone to grind wheat). Many small farms and homes in rural America relied on windmills to produce electricity for their homes well into the 1940s.

Using wind as a large-scale source of energy has its challenges, particularly because wind varies in strength and consistency of direction. The best areas for the placement of modern windmills are atop mountains or offshore. However, many people living in these areas complain that the machines are an eyesore and create hazards for wildlife.

Did you know?
Holland's windmills are still used today to catch offshore and onshore winds which turn wheels to produce electricity and grind grain.
4.

What could be considered the source of wind energy?

RENEWABLE ENERGY DERIVED FROM WATER
Hydro-energy. Hydro-energy is derived by directing moving water over blades or turbines. Water wheels are the earliest invention to use hydro-energy. The concept is simple. Moving water in a stream or river turns the paddles of a wheel, which causes other attached parts to move. While the first water wheels powered flour mills and lumber mills, by the late 1800s, they produced electricity for local use.

As demand for electricity grew, artificial systems were devised for creating a constant supply of moving water. Today, large hydro-electric plants are fed by water controlled by immense dams, such as the Hoover Dam on the Colorado River. Dam systems have proved the most successful use of renewable energy to date. The systems renew themselves by taking advantage of the water cycle. As the water passes through the dam, over the turbines, and then down the river, some of it evaporates into the atmosphere. When it rains, a portion of the precipitation falls upstream and runs back into the catch basin for the dam.
5.

A waterwheel is an example of

Wave energy. The power of moving water is not restricted to river systems. Wind moving over the surface of the ocean creates waves whose energy can be used to generate electricity. Wave energy is only feasible in areas where wave action is strong and reliable. These areas include the west coast of Scotland, northern Canada, the northeast and northwest coasts of the U.S., southern Africa, and Australia. The world's first such power generating station was built into the coast of the Scottish Isle of Islay and began operations in 2000.
Tidal energy. Tides caused by the pull of gravity from the Moon and the Sun also create a steady, predictable, and forceful movement of oceanic water. However, in order to be useful in the production of energy, the tidal movement must cause water to rise and fall a significant amount (at least 4 meters). In order for this to happen, the tidal water must be forced into a narrow inlet. Tidal energy is extracted when turbines are placed strategically in these areas. The Rance River in France has been used in this way. The Bay of Fundy in Nova Scotia has also been considered because it experiences tides higher than fifty feet due to the funneling of water into the narrow bay. The world's first offshore tidal station was installed as a prototype in 2003 off the coast of England.
6.

The most successful renewable resource in use today is

RENEWABLE ENERGY DERIVED FROM THE CORE
Geothermal energy. Geothermal energy is heat energy produced from within the Earth itself. The heat is used to produce steam, which is then used to heat homes and to warm greenhouses. This energy resource is considered renewable because the heated water is restored by the water cycle and the heat itself is continuously created in the core of the Earth as a product of the decay process of radioactive atoms.

This heat rises through the layers of the Earth and in some places breaks completely through to the surface, warming local water deposits and sometimes creating geysers. Iceland has 95% of its energy needs satisfied by tapping hot steam from the ground to power electrical generators. In some locations, neither steam nor hot water is available but extremely hot rock can be located by drilling. Scientists are considering piping water down to the rocks to heat it to steam that could then be collected.
7.

Energy that comes from the heat of the earth's core is known as:

NONRENEWABLE ENERGY SOURCES
Fossil fuels. Petroleum, natural gas, and coal are called fossil fuels because they are the byproduct of decayed plant and animal matter deposited during a much earlier time in the Earth's history. Among the multiple uses of fossil fuels, petroleum is refined into gasoline for transportation, natural gas is typically used to heat homes, and coal is burned to generate electricity.

Like biomass, fossil fuels hold the energy originally obtained from the Sun in chemical bonds. The heat generated when these bonds are broken is often used to heat water to create steam. The steam is then pressurized and released, creating a forceful flow against the blades of a turbine. The turbine is part of an electrical generating system.

The combustion of liquid hydrocarbons produces gases that quickly expand to many times the volume of the original liquid. In a combustion engine, the expanding gases are used to push pistons attached to the drive shaft, which causes the wheels of the machine to turn.

While fossil fuels are a very effective energy source, they take an immensely long time to form and are considered nonrenewable sources of energy. Since much of the world is highly dependent on fossil fuels, fossil fuel reserves are gradually being depleted. Their increased use is also creating environmental concerns.

Did you know?
Because fossil fuels received their energy from the sun long ago and must be extracted from far below the Earth's surface, these resources are sometimes referred to as "buried sunshine."
8.

Why are fossil fuel resources sometimes referred to as "buried sunhine"?

Nuclear energy. The spitting or combining of atomic nuclei (fission and fusion) creates massive amounts of nuclear energy which must be carefully controlled to be useful.

Fission reactions are used in nuclear power generating stations. The energy released from the fission reactions is used to create steam for electrical energy generation. This source of energy is considered non-renewable because once the atom has fissioned, it cannot be put back together. Drawbacks of this process include the release of excess energy into the environment and the production of radioactive decay material that must be stored for many centuries.

Fusion reactions, on the other hand, do not create radioactive waste. The power of the Sun is derived from fusion reactions at its core. Although scientists are able to create fusion reactions, they have not yet developed a technique for controlling their energy release. Therefore, these types of reactions are not feasible for the production of useful energy on Earth.
9.

Which of the following energy sources is in no way derived from the Sun?

10.

What process is used to release energy in nuclear form?

Electrical energy. Electrical energy is the flow of electrical charge. An electric current contains electrons moving through a conductor. This energy can be used to light bulbs, turn motors, and cook food. This type of energy is considered to be a secondary source because it is obtained from the conversion of other sources of energy, such as those mentioned above.
Thermal Energy Almost all of the matter around contains atoms. These particles are always in random motion and thus have kinetic energy. The total potential and kinetic energy related to the motion of all the microscopic particles in an object make up its thermal energy. When an object atoms move faster, its thermal energy increases and the object becomes warmer. When object are hot enough, the can even emit visible light (electromagnetic energy).

LET'S REVIEW!

In this lesson, you have learned that there are only two types of energy—kinetic energy (the energy of motion) and potential energy (stored energy). Within these two types, however, there are many different forms of energy available on earth. Some of these forms of energy, such as solar energy or hydro-energy, are renewable while others, such as fossil fuels and nuclear energy, are not. Renewable energy sources are those resources that can be replenished in a short amount of time. Nonrenewable resources, however, either take a very long time to be replenished or cannot be renewed at all. Regardless of whether an energy source is renewable, though, all forms of energy have both benefits and drawbacks that need to be carefully considered when deciding which form to use.
11.

Select all that apply.
Which of the following have energy stored as chemical energy?

12.

In most energy sources, such as fossil fuels, where is the energy originally derived from?

13.

Match the following with their proper definitions

a material made from plants or animals
a property capable of causing changes in matter
a carbon-based fuel thought to be derived from living matter
the energy of a moving object
stored energy
energy derived from chemical bonding between atoms
energy released during the fission (breaking apart) of an atomic nucleus or the fusion of two atomic nuclei