Visionlearning Glossary

A United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. For more information see http://www.nsf.gov .

Used in the following modules: Data: Using Graphs and Visual Data, Scientific Institutions and Societies, Visionlearning, Visionlearning Teaching Modules

In science, a negative control refers to a system that is identical to a treatment in all ways with the specific exception of the treatment itself. Thus, the negative control provides a measure of the natural fluctuations of a dependent variable due to factors other than the experimental treatment. For more information, see: Research Methods: Experimentation

Used in the following modules: Research Methods: Experimentation

Generally defined as neither one thing nor another. 1. Electrically neutral refers to having no net electrical charge, usually achieved by having an equal number of positive and negative charges, atoms are electrically neutral. 2. In acid/base chemistry, neutral refers to a solution that is neither acid nor base. A neutral solution contains equal concentrations of H⁺ and OH^-, and has a pH = 7.

Used in the following modules: Acids and Bases, Atomic Theory I, Atomic Theory II

The chemical process of making a solution of acid or base into a neutral solution by adding either base or acid, respectively. A process represented by the reaction:Acid + Base --> H₂O + Salt

Used in the following modules: Acids and Bases

A sub-atomic particle with no charge and a mass of 1.675 × 10^-27 kg. Neutrons are found in the nucleus of atoms. Compare to the proton.

Used in the following modules: Atomic Theory I, Atomic Theory II, Nuclear Chemistry, Scientific Ethics, The Mole

English alchemist, physicist, astronomer and mathematician born in Woolsthorpe-by-Colsterworth, Licolnshire (1643-1727). In 1672, Newton offered an experimental proof that light is composed of particles, and developed a theory of color based on the separation of white light through a prism. This theory was broadly (though not universally) accepted until the 18^th century. In 1687, he published the Philosophiae Naturalis Principia Mathematica, which many considered the most influential book in the history of science. In it, Newton presents his theories of universal gravitation and the laws of motion. He is credited, along with Gottfried Leibniz, for the development of calculus, and he demonstrated a consistency between Kepler’s laws of planetary motion and his theory of gravity, dispelling the final doubts in the scientific community over a heliocentric view of the solar system. He also contributed significantly to the development of new technology, inventing the reflecting telescope. For further information see Isaac Newton

Used in the following modules: Charles Darwin II, Data: Using Graphs and Visual Data, Energy, Gravity, Light I, Minerals I, Research Methods: Description, Research Methods: Experimentation, Research Methods: The Practice of Science, Scientific Communication: Understanding Scientific Journals and Articles, Scientific Institutions and Societies, The Scientific Method, Waves and Wave Motion

English nurse and statistician born in Florence, Italy (1820-1910). Nightingale observed that poor sanitation was the leading cause of deaths in field hospitals during the Crimean War, and became a key activist for hospital sanitation. She was a skilled statistician, and used statistical observations to convince the Members of Parliament of the medical conditions during the Crimean War. Nightingale was also extremely influential in the field of nursing: the Nightingale School of Nursing still teaches her care-giving principles. For further information, see covalent bond in which electrons are equally shared between bonding atoms. A non-polar covalent bond is formed when both atoms participating in a bond have an equal or nearly equal affinity for electrons (electronegativity). A non-polar bond will result in a symmetric distribution of electron charge across the bonding pair. Compare to polar covalent bond, polar molecule.

A molecule that has an equal distribution of bonding electrons across it. Non-polar molecules are formed by non-polar covalent bonds or when polar covalent bonds result in a symmetric distribution of electrical charge, the configuration + - - + for example. Compare to polar molecule.

Also called a Gaussian distribution or a bell curve, the normal distribution is one of a family of continuous probability distributions in which the probability of observing any specific value is evenly distributed about the mean (µ) of the dataset and falls off continuously as one moves away from the mean value in either direction. The standard deviation (σ) of the dataset describes the spread of a normally distributed set of data as seen in the figure below:

A group of polymers made of repeating units of phosphoric acid and sugar to which nucleotide bases are attached. The two most common examples are DNA and RNA.

Used in the following modules: DNA II

A nitrogen containing base that is a constituent of a nucleic acid. Examples are adenine, guanine, thymine, uracil, and cytosine.

Used in the following modules: DNA I

1. [Atomic] A tiny, dense positively charged mass at the heart of an atom. The nucleus is composed of protons and neutrons, and contains nearly all of the mass of the atom while occupying only a tiny fraction of the volume. 2. [Cellular] The internal structure present in some cells that contains genetic material.

Used in the following modules: Atomic Theory I, Atomic Theory II, Cells, DNA II, Nuclear Chemistry, Research Methods: Modeling, The Periodic Table of Elements

In statistical testing, a null hypothesis (H₀) commonly takes the form of a statement suggesting that an observed result or effect is due to random chance. The null hypothesis is put forward as the counterpart to an alternative hypothesis (H₁), and is presumed correct until statistical testing shows otherwise. For example, in an evaluation of data regarding the pain relieving properties of a new drug, the null hypothesis would state that the new drug has no effect beyond that of a control. The null hypothesis is never proven by statistical testing; either H₁ is accepted in favor of H₀, or H₀ is “not rejected.”

Used in the following modules: Research Methods: Comparison, The Case of the Ivory-billed Woodpecker

Officially United States of America v. Karl Brandt, et al., was the first of the Trials of War Criminals held before U.S. military court in the aftermath of World War II. Twenty of the defendants were medical doctors and three were Nazi officials who were all accused of having been involved in Nazi human experimentation. Of the 23 defendants, seven were acquitted and seven received death sentences; the remainder received prison sentences ranging from 10 years to life imprisonment.

Used in the following modules: Scientific Ethics