Science & Nature

A vein is a blood vessel that carries carbon dioxide-rich blood away from the tissues in the body and toward the heart. The heart then pumps it into blood vessels in the lungs, which exchange...

As the United States, Australia and other developed countries search for alternative fuel sources, coal-to-liquid (CTL) plants have won considerable attention. Also known as "coal gasification,"...

Photosynthesis is the process by which plants and some single-celled organisms produce sugars from sunlight and carbon dioxide. These sugars then become the food used in cellular respiration. In...

Life as we know it is carbon-based. A carbon skeleton is the chain of carbon atoms that forms the "backbone," or foundation, of any organic molecule. Because of carbon's unique ability to form...

Gypsum is a naturally occurring form of calcium sulfate, CaSO₄·2H₂O. It is used in the building trade for gypsum board, also called drywall, and is an ingredient in plaster of...

Greenhouse gases (GHGs) are gases that contribute to the "greenhouse" effect, in which heat becomes trapped within the earth's atmosphere and causes the temperature of the planet to rise. In an...

External respiration is part of a three-part process that includes external respiration, internal respiration and cellular respiration, which together constitute how we exchange gases with our...

Respiration is a biological process that involves the exchange of gases. The most common form of respiration involves the absorption of oxygen and the release of carbon dioxide. This common form...

Carbon is an element that is the main building block of all living things, including plants, invertebrates and vertebrates. A carbon skeleton is a linkage or chain of carbon atoms.

Plant respiration is the opposite of photosynthesis, which is a biological process performed by green plants that creates oxygen and releases it into the air. During respiration, plants absorb...

When most of us think about respiration, we think about breathing, or the process of inhaling and exhaling. That's correct, but only partially so. Respiration involves both the acts of gas...

As any aquarium owner knows, algae can be unsightly in an aquarium and detract greatly from the beauty of the sea life within it. One of the main causes of algae is high levels of phosphates in...

Diamonds, a special form of carbon created in an environment of extreme pressure and temperature, are some of the oldest minerals on Earth, but it has been in just the last century that humans...

While iron has been used by humans for around 3,000 years, it has only been in the last 150 years that processing iron into its alloy steel has been commercially viable. Iron is a very common...

Saccharin is the oldest form of artificial sweetener discovered by Constantine Fahlberg, who accidentally spilled a chemical on his hand. While consuming bread at dinner, he noticed that the...

Also called sodium bicarbonate, sodium hydrogen carbonate is white compound formed from one sodium atom, one hydrogen atom, one carbon atom and three oxygen atoms. Sodium hydrogen carbonate is...

Active, or activated, carbon water filters are used to remove contaminants from water. In most cases, this filtration is done on water intended for drinking or cooking purposes, though it may be...

There are two types of compounds from which hydrogen is generally split---hydrocarbons and water---but there are many methods of doing so. The main method of mass-producing hydrogen is from...

Guar gum and xanthan gum are similar products in that they both have properties that make them efficient thickening agents. Both are complex carbohydrates and both entered the commercial world...

Salicylic acid (SA) is a weak acid used to make aspirin. Its chemical formula is C6H4(OH)COOH, in which the C6 forms a benzene ring with alternating double- and single-electron-pair carbon-carbon...

When most people think of the air in Earth's atmosphere, they do not think of it as being composed of many different gases. In reality, the atmosphere is made up of many different gases in...

Steel is an alloy consisting of iron and carbon. The chemical and physics properties of steel are dependent on the chemical composition of the steel itself.

As Earth's population increases, many of the natural resources needed to sustain human life decrease. As a result, scientists have devised the concepts of the ecological and carbon footprint to...

Photosynthesis allows plants to convert water and carbon dioxide into carbohydrates in the form of sugars and starches. Plants carry a green chemical called chlorophyll that, when combined with...

A carbon sink is any mechanism that removes a greenhouse gas (GHG) from the atmosphere. The most important GHG is carbon dioxide. Carbon sinks can be either natural or man-made.

Sucrose, or table sugar (C₁₂H₂₂O₁₁), is one of the best-known organic compounds in the world. Sucrose is a disaccharide, which means it is two simple...

Your lungs are a pair of organs situated in your chest behind your ribcage. The primary function of your lungs is breathing, but they also play another vital role as part of your excretory system.

Plants use a complex chemical reaction called photosynthesis to create food from light energy, carbon dioxide from the atmosphere, and water. Each of these performs a critical portion of the...

Plants use a process called photosynthesis to create food. It requires a combination of water, light energy and carbon dioxide for the chemical reaction to take place. In order for photosynthesis...

The process of making Damascus steel blades has been around for thousands of years. The steel used in the making of Damascus blades is composed of an alloy of metals that provide both strength and...

Stomata are anatomical features that are located on the underside of the leaves of plants that live on land. These structures, which are the 'pores' of the plant's skin, provide openings for the...

All living things have carbon in their molecular structure. Carbon 14 results from cosmic rays sending thermal neutrons toward Earth. These interact with nitrogen in the atmosphere to produce a...

Greenhouse gases are gases in the atmosphere that absorb and emit radiation within the thermal infrared range. As a result, they slow and block infrared radiation from getting from space to the...

Photosynthesis allows plants to convert light into food, removes carbon dioxide from the atmosphere and releases oxygen into the atmosphere. Without plants that perform photosynthesis, the oxygen...

The greenhouse effect begins with that part of the Sun's radiation that reaches the Earth's surface, and is not deflected either by the planet's magnetic sphere or it's cloud cover. Most of this...

Resistors are electrical components designed to limit the amount of current flow in circuits. The values of their resistance may be either fixed or variable. Fixed resistors share common elements...

"Dry ice" is a descriptive term applied to solid carbon dioxide gas, CO₂. Flakes of dry ice can be produced by rapidly expanding the pressurized gas (thus cooling it). The carbon dioxide...

The cells in our bodies require certain elemental molecules to function, reproduce and repair themselves. Sometimes these molecules are energy structures such as the ATP molecule that are pulled...

Hydrogen is the lightest and simplest element known to exist in the universe. A hydrogen atom is composed of a single electron orbiting a single proton. It is a gas at normal temperature and...

The distinction between organic and inorganic chemistry is not a trivial one. Courses of study in universities throughout the world are structured based on the distinction. And even among those...

Photosynthesis is the process by which plants convert solar energy into the life-sustaining chemical energy called ATP. Photosynthesis occurs in plants and some species of algae that are...

Dry ice is frozen solid carbon dioxide, CO2. It sublimates directly from a solid to a gas, which makes it an interesting item for experiments. According to Brian Rich's science website, a pound...

Linolenic acid, strictly speaking, is not one acid but two. When the name is generically used, the one usually meant is alpha-linolenic acid (Figure 1). Found in many foods and food-based...

Glucose is a tiny molecule of sugar. Glucose circulates in the blood and is used as energy for cellular reactions. Glucose is found in the diet in the form of carbohydrates. The larger...

Phytoplankton are tiny photosynthetic organisms that are the major producers of marine life. They form the foundation of the food web for most marine life. They are responsible for half of the...

For many years scientists had to be content only with theories on how plants created energy. Only with modern age equipment have scientists been able to prove that photosynthesis takes place and...

A flower contains a plant's reproductive organs. In order to reproduce, specialized sex cells found in the plant's pollen must first deposit on the stigma of the flower. Once deposited, the pollen...

Since it was developed by Nobel Prize-winning scientist Willard Libby in 1947, radiocarbon dating has been one of the most important tools available to archaeologists, and just about anyone else...

"Dry ice" has nothing to do with water. Dry ice is solidified carbon dioxide. Carbon dioxide is the gas produced by our bodies when it oxidizes carbon-containing food we have consumed. We breathe...

Iron, one of the most abundant elements on Earth, helped give rise to entire civilizations and is the key ingredient in steel, without which many of our modern structures would not be standing....