AP Classes

All light that is not absorbed by a prism, even black light, is separated out into a continuum of different wavelengths or colors. The speed of light through a medium is a function of its...

In the United States, a district is an area from which a candidate is elected to a legislative seat. A precinct is the smallest area from which votes are collected, and it has a single polling place.

Progressive tense indicates actions or states of being that occur over some duration of time. The progressive tense is constructed of a form of the verb "to be" and a gerund ("-ing" form of a verb).

Students are often frustrated when reading school textbooks. They know that they should be taking notes on the reading, but are unsure how to go about it. This simple classroom-tested technique...

Heat exchangers are mechanical devices used to transfer heat from one fluid to another over a solid surface. They are designed to be efficient and the transfer of heat occurs either through...

Ballasts are heavy material, often seawater, placed in the hold of a ship to gain stability. Routine ballast discharges from oil tankers account for a large portion of the total oil (including...

A trapezoid is a quadrilateral with two parallel sides. In geometry, you may be asked to find a missing side of a trapezoid, given the area and height. For example: a trapezoid has an area of 171...

Information on how you can easily and efficiently learn to speak Spanish. Follow these tips to start speaking Spanish today.

Children are naturally curious about bees. Bees are an important part of the life cycle of plants, as they collect and distribute pollen. About a third of all the food we eat comes from...

Sedimentation is the separation of a dilute suspension of solid particles into supernatant liquid and concentrated slurry. Examples of solid particles include steel, iron, calcium, lithium and...

Secondary school students often become more preoccupied with grooming their hair, nails and overall personal hygiene. Consequently, secondary schools emphasize the importance of students learning...

Sodium carbonate, a substance used most commonly in laundry detergent, is a white powder. In chemical experiments, it serves as an electrolyte, allowing it to conduct electricity. In industry,...

There are three forms of weathering, constituting physical, chemical and biological processes. Though weathering can be confused with erosion, there are subtle differences. Erosion occurs with the...

Almost all high school and college teachers require this. They are right, if done correctly, you will do better on your test grades. Annotating is not that hard if you know what you are looking...

Increasing curves on a graph is a common problem type given in advanced or college algebra. You are given a sin or cos function and asked to increase or decrease the appearance of the graph's...

Mountainous ecosystems are fragile environments. They are home to numerous isolated and threatened animal species. Yet mountain regions also supply fresh water to millions of people living in...

The aorta, which is separated into the thoracic and abdominal portions by the diaphragm, is one of the body's most critical blood vessels. The enormous blood pressure in this artery makes it...

Mercury is widely distributed in nature. It is highly poisonous to both plants and animals. Chronic exposure to mercury has far-reaching effects on human health and the environment.

The bell curve is a lay term for what statisticians call a normal distribution; it's called a bell curve because the shape of a normal distribution is in the shape of a bell. According to David...

Bacterial photosynthesis is one of the most primitive versions of photosynthesis. It uses organic matter or sulfur compounds as electron donors rather than the ATP (adenosine triphosphate) in...

According to the Math Forum at Drexel University, writing a geometrical proof is more like writing an essay than performing a set of calculations. Your goal is to clearly state your reasons for...

Percentiles are used to compare scores across a larger sample, such as a national college admissions test like the ACT and SAT. Your percentile tells you what percentage of people you scored...

For deep wells, it can be difficult to determine the depth of the water because you cannot see the bottom. However, using physics it is possible to calculate the depth of the water because once...

The steradian (sr) is the SI unit of the solid angle (Greek letter Omega). According to calculator.org, one definition of a solid angle is a certain area (for example, a circle) on a sphere's...

The tachometer is an instrument used for measuring rotational speed. The speed measured is usually that of a rotating shaft being driven by an engine. Tachometers are commonly installed in sports...

Look around and you will probably see many rubber products around your house. The rubber in most of our products is not pure natural rubber but a processed form of rubber to make it hardier....

Lithium ion batteries began appearing in the early 1990's. They have the highest energy density of all rechargeable batteries. But due to safety concerns, developers had to incorporate special...

Historical accounts of levitation are recorded in paranormal studies, though few if any have been confirmed as actual happenings. Interestingly enough, scientists in the field of quantum physics...

A heat pump heats or cools a building by conveying heat from or to the outdoors. Heat pumps are widely used for heating in moderate climates.

Water is a simple molecule with profound physical and chemical properties. One property, its ability to split into two ions (ionization), provides us with a method to determine the acidity or...

Fluids are everywhere. Did you know that gases, in addition to liquids, are considered fluids? Knowing how to calculate the pressure at a depth within a fluid is an important skill to have in...

Scientific notation is all over the place in... well, science. The reason it's very useful is because it's a compact way to write very big or very small numbers. Up until the late 1700's, people...

The digestive system functions to process food completely, so that the body can easily absorb the nutrients we need to live and grow. The organs involved work together in perfect harmony, which...

A titration lab is performed to determine the pH of a solution by finding the endpoint of a reaction. To perform a titration lab, you will need a burette, beaker, litmus paper, indicator solution,...

The Battle of the Alamo (1836) in San Antonio, Texas, is celebrated as a battle between a small band of Texas defenders against a large, invading Mexican army. The weapons used were as varied as...

Prior to taking calculus, students must contend with equations. Once they reach that higher level of math, however, they learn a new mathematical construct. A function associates one and only one...

Knowing the overall behavior of a graph can be important, especially in higher math when you need to know limits and larger trends. Determining if a function is even or odd in overall behavior is...

First of all, definitions. The domain of a function is all of the values that 'x' can take. When I say 'can take', I mean the values that when plugged into the function will make mathematical...

Quality learning is important in schools and in education today. School districts are often cutting back on the amount of time each subject has or on the amount of days per school year. At the...

The human body is a wondrous creation, a machine with nearly perfect efficiency. More than a dozen systems of organs and tissues work together to give us life.

The testes are the primary sexual organs of the male body. Each produces millions of sperm and large amounts of hormones throughout a male's lifetime.

Buffers are simple systems of molecules that have profound implications in living cells and test tubes. Without them, cells would not survive and biochemical research would be flawed.

Advabced Placement (AP) World History is a great way to expand your knowledge on other countries' histories. Though many people think specifically of European history outside of American history,...

Sir Isaac Newton (1642-1727) may be best known for the story of "discovering gravity" when an apple fell on his head. He also outlined the three laws for motion that are necessary to the study of...

Biophysics are the study of organisms on the planet, and how they interact with other living things and ecosystems. Biophysics focus on everything from the molecular level to the fully developed...

Acids and bases play a critical role in the fields of biology, chemistry, biochemistry and physiology. To understand the intricate details of these areas of study, you must first understand acids...

Coenzyme A (or CoA) is an essential assistant to several critical enzymatic processes in the human body. It is usually found linked to carbon chains destined for further processing, and in this...

Teachers handle conflicts on a daily basis. They handle conflict in the classroom between students, and between themselves and students, administrators, and parents. They use different strategies...

Selecting a sample from a population takes many factors into account, including cost, confidence level, and sampling method. In simple random sampling without replacement, defining the smallest...

Growing a bacterial culture in a petri dish is not difficult and can be done in the classroom and at home if you follow the proper steps and guidelines. Bacteria are living things that require...