Science

Direct sunlight is important in the natural world and elsewhere because it provides the energy which fuels the growth of plants that are necessary for the survival of all life forms on the planet.

The moon is our closest celestial companion. Its gravitational forces affect the Earth's tides, with both the full and new moons responsible for the highest tides. The moon's gravitational pull is...

Moonlight differs from sunlight in many ways, primarily in that moonlight is actually reflected sunlight that bounces off the moon in the direction of the Earth. Changes in the power density of...

Convection refers to the transfer of heat via a moving substance, such as air or water. Convection currents are the manifestation of those movements.

A geologic ladder of time represents the different sections of history in rising rock layers that may be exposed, due to weatherization, by excavation. Scientists segment the different eras of...

Birds and tropical vacationers alike know that climate is affected by latitude. Because the earth is a sphere, the surface of the earth does not receive uniform amounts of solar radiation. This...

Solar radiation has positive and negative effects on the climate, ecosystem and health of organisms living on earth. The negative effects are often associated with man-made chemical radiations;...

Finding a whole mammoth tusk or a hominid femur is rare. You will find far more fossils with a sifter; this can be a wooden frame with a strong mesh screen, or a smaller cylindrical or square hand...

The jet stream can best be thought of as a river of wind that moves through the Earth's troposphere. Usually going from west to east, this stream of moving air can be extremely powerful, moving on...

Currents of fast-moving air form the jet stream six to nine miles above the Earth's surface. These currents help weather forecasters predict the weather. Meteorologists use computer models to...

Neodymium is not one of the best-known of chemical elements, but it is one of the most useful in today's society. Neodymium is relatively safe to produce and use, exists as a common metal on the...

Solar energy has been harnessed by humans for thousands of years for heating purposes, and more recently for electricity generation. Solar power is an extremely vast resource, but it has some...

The Earth's core is solid at its center with a liquid outside. Part of that liquid is molten iron, which, at the Earth's surface, has a magnetic tendency. Some iron compounds are naturally...

Since the dawn of space travel, scientists have concerned themselves with the effects of radiation on astronauts. Several kinds of radiation occur almost instantaneously and can cause a variety of...

Ever since the dawn of time, man has wondered about his origins. How did we get here? Were we crafted by an intelligent creator or created by an evolutionary process? Scientists today still argue...

The alkaline earth metals are reactive metals that share similar properties. They are arranged together on the periodic table and have similar configurations.

The alkaline earth metals are a group of elements on the periodic table that are highly reactive and share common traits. These metals, which are found in common compounds like marble and chalk,...

Science is humanity's quest to understand the universe in which we live. Science is constantly evolving. The Earth, after all, was once thought to be flat. It is highly unlikely, though, that...

Created by radioactive decay and in the cores of stars, helium gas is a valuable commodity on Earth. Though used to float party balloons and Thanksgiving Day Parade characters, it also supercools...

A combustible substance is a substance that can be burned. Usually this means burned in the open air or atmosphere. If nitrogen could burn, all life on earth would have been destroyed long ago,...

The history of our planet is rife with disasters that have devastated local populations and global events that have threatened the very existence of life itself. The restless nature of the Earth...

Moon phases vary slightly as the moon rotates around the earth and the appearance of the moon changes, although the moon itself remains the same. Whether you're an amateur stargazer or follow your...

Jet streams are among the most powerful weather phenomena on Earth. They are bands of wind in the top of the troposphere (the lowest region of the Earth's atmosphere). Jet streams have a big...

Scientists get really excited whenever traces of water are found on another planet; newspapers will announce it somewhere on the front page. To the uninitiated this is perhaps confusing---water is...

The Earth is a giant magnet, with a north magnetic pole and south magnetic pole like the two ends of a bar magnet. And like a bar magnet, the Earth is surrounded by a magnetic field that interacts...

The atmosphere surrounding the Earth is made up of many gases, the most prevalent of which are nitrogen and oxygen. It also contains water vapor, dust and ozone. The lowest layer of the atmosphere...

The ozone layer is found from 10 to 20 miles above the earth's surface. It is composed of oxygen atoms and has a blue tint. As sun rays pelt the earth, the ozone layer absorbs part of the...

Fossils give modern civilization a chance to look back at life in prehistoric world. They are found all over the earth and come in many forms. Fossils can be found as calcified remains of...

The surface of the Earth is not a stationary solid surface. This outer layer of the Earth is the lithosphere. It is actually broken up into pieces like a giant jigsaw puzzle. These broken pieces...

The word "stratospheric" is a descriptive for anything relating to the stratosphere, the second of the Earth's atmospheric layers situated immediately above the troposphere, the lowest layer where...

Geophysics is an earth science that combines geology and physics. In other words, it is the study of the physics of Earth and other planetary bodies. Planetary science is an example of a field...

The mantle is one of the three major layers of the Earth, which geologists often compare to a hard-boiled egg, with the mantle analogous to the white of the egg. The mantle is largest of the...

There is a great deal of energy to be tapped underneath the Earth. This energy, known as geothermal energy or geothermal power, is used today to generate 0.3 percent of the world's electricity...

Renewable resources are products that can be produced by the earth without running out. Find out what renewable resources are with tips from a math and science teacher in this free video on...

Global warming is a concern for everyone. Most people agree that this trend is occurring, but they disagree on the cause. One issue is whether or not sunspots can be one of the causes of global...

When heat comes to Earth from the sun, various forms of radiation are absorbed in the atmosphere and converted into infrared radiation. Discover why ultraviolet rays can be more dangerous than...

Invented in the early 1980s, neodymium magnets are, as of 2009, the strongest kind of permanent magnet available. Their strength, small size and low cost have made numerous advances in personal...

Strong visual materials make any presentation more fun. This Earth globe display demonstrates the outer land and water masses of the Earth and the center magma, mantle and crust formations. Using...

A compass, in its simplest form, is a piece of magnetized material that is more or less linear in shape. It responds to Earth's magnetic field by orienting itself along a north-south axis.

Throughout the existence of the human species, the existence and substance of the universe has been an ongoing question. Different ages have developed different theories and answers--some...

The periodic table is a scientific table that arranges the known metals into an easily read format. The periodic table is the cornerstone to chemistry and our understanding of how elements react...

Earth's surface is primarily composed of seven major elements that are found in abundance, including oxygen, silicon, aluminum, iron, magnesium, calcium and potassium. Learn about the major types...

It is common knowledge that there are four seasons on Earth. Winter, spring, summer and fall pass each year. But what causes the four seasons?

The lithosphere is an important part of the theory of plate tectonics. In geologic terms it represents the rocky, rigid plates that move across the rubbery asthenosphere. The lithosphere is just...

The earth's mantle, core and surface have varying chemical compositions, but the earth is generally made up of eight main elements, within which there are four super abundant elements. Learn about...

Earth has a magnetic field with certain points that are considered poles, and a pole occurs when a magnetic field is at a 90-degree angle. Discover how the magnetic north and south poles are...

Earth's magnetic field, or magnetosphere, is the stuff of both science and science fiction. Generated by forces deep within the planet, the magnetic field is what orients all compasses, extends...

In an environment of increasing demand for renewable energy resources and derivatives, geothermal energy is one of the resources toward which industry is turning. "Geothermal" means heat from the...

Bacteria are extremely common and abundant in every habitat, and it's estimated that their are 5 nonillion bacteria on Earth. Learn about the role of bacteria in nutrient cycles and as decomposers...

Geothermal energy is any heat energy that has built up under the Earth's surface and is available to be used as a power source. Today it accounts only for 1% of the world's energy. However,...