Measurements and Mathematics Terms

1. The basic unit of electric current in the meter-kilogram-second system: An ampere is equivalent to one coulomb per second.
2. A unit of electrical current or rate of flow of electrons: One volt across one ohm of resistance causes a current flow of one ampere.

A measure of the flow of current (in amperes) over one hour when the rate of flow is one ampere: An ampere-hour is equal to 3600 coulombs (standard international unit of electric charge).

The ampere-houris used to measure battery capacity.

A unit of length equal to one ten-billionth of a meter (10 meters or one-ten-millionth of a millimeter): The angstrom is used to measure the wavelengths of electromagnetic radiation.

It was named after Anders Jonas Ångström (1814-1874), a Swedish astrophysicist.

Out dated or obsolete units of mass, formerly used in pharmacies:

• Twenty grains equal one scruple.
• Three scruples equal one dram.
• Eight drams equal an apothecary's ounce; oz apoth.
• Twelve such ounces equal an apothecary's pound; lb apoth.

There are 7,000 grains in one pound avoirdupois or 0.454 kilograms.

Not precise; estimated; inexact: An approximate measurement is close enough to the true number to be useful.

A portion of the circumference of a circle that is represented as a curved line: The rainbow has the shape of an arc, or is bent in the shape of an arc, or in the form of a crescent.

A metric unit of area, equal to 100 square meters (119.6 square yards): 100 ares equals one hectare.

The measurement or extent of a two-dimensional surface enclosed within a boundary: The islands cover an area of 7,000 square kilometers.

Jim's geometry teacher told the students to assess the area of a triangle.

A branch of mathematics usually concerned with four operations: adding, subtracting, multiplication, and division of positive numbers: "Math" is the short form for arithmetic and has to do with numbers and calculating

The average distance from the planet Earth to the Sun, which equals 149,597,870 kilometers or 92,955,800 miles: For simplicity, an astronomical unit is usually rounded off to 93,000,000 miles or 149,637,000 kilometers.

An astronomical unit is used to describe planetary distances.

Light travels this distance in approximately 8.3 minutes.

In physics, a unit of pressure equal to 760 torr, 1013.25 millibars, or 1.01325 x 10⁵ newtons per square meter: The standard atmosphere is a unit of pressure, the pressure that holds up or supports a column of mercury 760 millimeters high at sea level and at 0°C.

The actual pressure exerted by he atmosphere fluctuates around this value, which is assumed to be standard at sea level and zero degrees centigrade/32 degrees Fahrenheit, and is used when dealing with very high pressures.

The terms used here are located in this unit.

Clocks that are regulated by natural resonance frequencies of particular atoms, and display a continuous count of seconds: The Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig is where the the atomic clock in Germany is located.

The time that is precisely assessed by an atomic clock: The atomic time can always be read on the internet, that means on a smart phone, iPhone, or on the computer.

The sum of several quantities divided by the number of those quantities: To find out the average of 10, 20, and 24, Mary had to add up the numbers, then divide by 3 which resulted in 18.

The number of carbon atoms in twelve grams of the carbon-12 isotope: Avogadro's const indicatesant the number of atoms or molecules in a mole of a substance, equal to 6.022 52 × 10 23

Avogadro's number is the relative atomic mass of any element, expressed in grams and contains this number of atoms.

It is named for an Italian physicist Amedeo Avogadro (1776-1856).