Manhattan Prep Vocab List 1 Flashcards
A.U.
Astronomical Unit. 1 A.U. = average distance between the Earth and the Sun, or about 93 million miles. Distances within the solar system (Sun, Earth, other planets, asteroids) are often more easily expressed in A.U. Note that stars are much further away; the distance to the nearest star besides the Sun is about 4 light-years, or about 250,000 A.U.
Acceleration
Typically, the rate at which an object’s speed increases. In common language, when you accelerate, you go faster. The higher your acceleration, the more quickly your speed increases. In science, you can also use acceleration to talk about a decrease in an object’s speed or even a change in its direction of motion (all of these changes require “accelerations”).
Aerosols
A substance held under pressure and released as a spray in the air.
Altitude
Height above the Earth’s surface.
Amino Acid
The building block of proteins. A molecule of an amino acid contains both an amine group (a group of atoms containing nitrogen) and an acid group (COOH). Amino acids are linked together to make much bigger protein molecules.
Angstroms
A unit of length equal to one hundred-millionth of a centimeter, or one-ten-billionth of a meter. Used mainly to express distances between atoms or to measure the wavelengths of certain kinds of electromagnetic radiation.
Arbitrary
Based on random choice.
Atomic nuclei
The centers of atoms. Atoms are the building blocks of ordinary matter, or stuff.
Atoms can be bonded into molecules. Atoms are themselves composed of electrons, protons, and neutrons. The light, negatively charged electrons whirl around the heavy, positively charged nucleus, which contains the protons and the neutrons. The plural of “nucleus” is “nuclei” (noo-klee-eye).
Boiling Point
The temperature at which a substance turns from liquid to gas, or “boils.” The boiling point of water is 212 degrees Fahrenheit = 100 degrees Celsius. The boiling point of other substances may be much higher or much lower than that temperature.
Capillary Tube
A very thin straw-like tube of glass. Because water is attracted to glass, water or water-based solutions are drawn easily into capillary tubes.
Carbohydrate
Organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. They are made up of the elements carbon, hydrogen, and oxygen in specific patterns. Carbohydrates are often produced by plants and can be broken down to release energy in the animal body.
Carbon Dioxide
A colorless, odorless gas that is naturally present in the air and is absorbed by plants in photosynthesis to make carbohydrates. Carbon dioxide is re-emitted into the atmosphere when plants or fossil fuels (made out of long-dead plants) are burned. Carbon dioxide is a greenhouse gas: it traps heat from the Sun and warms the Earth. The chemical formula is CO2. One molecule of CO2 contains one atom of carbon (C) and two atoms of oxygen (O). The “di-“ prefix means “two.”
Carbon Monoxide
A colorless, odorless gas that is toxic. The chemical formula is CO. One molecule of CO contains one atom of carbon (C) and one atom of oxygen (O). The “mono-“ prefix means “one.”
Combustion
The process of burning something. This usually involves chemically combining that substance with oxygen, a process that releases heat and new substances. For instance, burning coal (which is essentially the element carbon) typically releases a mix of carbon monoxide and carbon dioxide.
Comets
Large objects (though smaller than a planet) made of ice and dust that orbit the Sun. Unlike planets, which tend to have nearly circular orbits, comets usually have very elliptical (oval) orbits that take them far away from, and then close by, the Sun over a period of many years.
Concentration
The amount of some substance contained in a certain volume of a solution or mixture. For instance, the concentration of salt (sodium chloride) in normal seawater could be expressed in grams of salt per liter of seawater. (Grams are a measure of mass or amount, while liters are a measure of volume. One kilogram, or 1,000 grams, of anything weighs a little more than 2 pounds at the Earth’s surface. A liter is a little more than a quart, which is a fourth of a gallon.)
Cytoplasm
In biology, the fluid filling of a cell where many chemical reactions take place.
Density
The mass of something divided by its volume. A substance that is denser than water will sink (unless you shape it to include air, which is much less dense than water). A substance that is less dense than water will float, even if it is not shaped to contain air.
Diameter
Distance from the center of a circle to an edge.
Diffuse
(As a verb, pronounced “diff-YOOZ.”) When particles diffuse, they move from an
area of high concentration (where they are very common) to an area of low concentration (where they are not very common). This happens in water (aqueous) solutions because particles are free to move around in liquids, and the invisible but constant jiggling and jostling of molecules at room temperature causes them to mix. So, after a while, a tiny area that was initially very concentrated in salt, say, will become less concentrated as the salt diffuses throughout the larger solution.
Directly Proportional
Two quantities are directly proportional if they have this relationship: when one of them doubles, so does the other. Likewise, if you cut one of the quantities in half, the other quantity is reduced by half as well.
Dissolve
When a solid dissolves in a liquid, the solid is incorporated into the liquid. The color of the liquid may change, but there is no longer any visible solid left. The result is often called a solution.
Ecological
Having to do with a environment that harbors life.
Flask
A container or bottle. Various kinds of glass flasks are often used in laboratories.
Freezing Point
The temperature at which a substance turns from liquid to solid.
Frictionless
Smooth. Friction is the resistance caused by one object moving against another.
Friction saps energy from that motion and turns it into waste heat. So if motion is frictionless, then the motion does not lose energy to friction.
Gene
A segment of genetic information on the DNA molecules that cells carry.
Graduated
In lab: having marks on the side for measurement. A graduated cylinder is marked like a ruler, allowing you to measure the volume of liquid contained in the cylinder.
Gravitational Field
Gravity is the natural pull of one object (such as the Earth) on other objects (such as you). At least one of the objects must be very massive, and the objects should be reasonably close, for the force of gravity to be significant. Technically, the Earth creates around itself a “gravitational field” in space, and then objects in that field feel that field and, as a result, are pulled toward the Earth.
Heptane
A hydrocarbon made of the elements carbon and hydrogen and predominantly used in fuels such as gasoline. “Hept-“ means “seven,” and each heptane molecule has 7 carbon atoms in it. The chemical formula of heptane is C7H16. When hydrocarbons such as heptane are burned, or combusted, they react with oxygen from the air to release heat and byproducts such as water and carbon dioxide.
Hexane
A colorless liquid hydrocarbon, made (like heptane) from carbon and hydrogen. “Hex-“ means “six,” and each hexane molecule has 6 carbon atoms. The chemical formula of hexane is C6H14.
