Knewton Chapter 1: Identify and Use the SI Units for Temperature and Time

SI unit

- kilogram (kg), for mass. - second (s), for time. - kelvin (K), for temperature. - ampere (A), for electric current. - mole (mol), for the amount of a substance. - candela (cd), for luminous intensity. - meter (m), for distance.

Water

1 g/ml or 1 g/cm^3

Time

A measurement of the length of time taken by a process. The SI base unit of time is the second (s). Small and large time intervals can be expressed with the appropriate prefixes; for example, 3 microseconds = 0.000003 s = 3 × 10−6 and 5 megaseconds = 5,000,000 s = 5 × 106 s. Alternatively, hours, days, and years can be used.

Dimensionless quantity

A quantity to which no physical dimension is applicable. It is thus a bare number, and is therefore also known as a quantity of dimension one. Dimensionless quantities are widely used in many fields, such as mathematics, physics, engineering, and economics.

Temperature

An intensive property. The measure of heat energy present in an object. The SI unit of temperature is the kelvin (K), and it is the temperature we use most frequently in science. The IUPAC convention is to use kelvin (all lowercase) for the word, K (uppercase) for the unit symbol, and neither the word "degree" nor the degree symbol (°). Water freezes at 273.15K. Water boils at 373.15K. In the kelvin scale, 0 K is absolute zero: the point at which all motion stops, a temperature which can never be reached exactly (nor can a negative Kelvin temperature be reached).

Length

Consider meaning a distance traveled. Measure in inches, feet, yards, mile, and meter (science). Tiny distance expressed in millimeter and large distance in kilometers.

Convert Fahrenheit to Celsius

Follow the equation here: C = (F - 32F) x (5C/9F)

Convert Celsius to Fahrenheit

Follow the equation here: F = (9F/5C) x (C) + 32F

Meter

Meter was once defined as a particular fraction of the distance from the equator to the north pole, but it was eventually revised to be more universal.

Conversion Factors

Kilo - 10^3 Mega - 10^6 Giga - 10^9 Tetra - 10^12

Kilogram

Kilogram was once based on the mass of a liter of water, but there is some variance in this quantity with temperature and pressure. Therefore, a more rigid definition was adopted with the metal cylinder, which is stored in France.

Density

Mass per unit volume Ex: kg/m^3 - SI units g/cm^3 g/mL Equation: Density = (Mass / Volume)

Mass

Mass, or the amount of matter present in object, is measured in kilograms. This was originally defined as the mass of a liter of water. Now, it's more refined, equal to a particular cylinder of a platinum-iridium alloy that is kept in France, as this will not vary with temperature and pressure the way water does.

Specific Gravity

Mathematics Definition: specific gravity = (density of sample substance / density of reference substance.Specific gravity is a comparative quantity, because it compares the density of some substance of interest (the sample) to the density of some standard substance (the reference).

Base Units of the SI System

Measured: Name: Symbol: length | meter | m mass | kilogram | kg time | second | s temperature | kelvin | K electric current | ampere | A # of substance | mole | mol lum. intensity | candela | cd

Volume

The amount of space something occupies. The unit depends on length. Volume is mostly measured in liters.

Scientific Notation

This consist of a single digit followed by a decimal point and some other numbers depending on how many sig figs are in the value. The number is multiplied by 10 which is raised to an exponent.

Celsius

This is also allowed in the SI system, with both the word "degree" and the degree symbol used for Celsius measurements. Celsius degrees are the same magnitude as those of kelvin: the two scales differ only in where they place their zero point. Water freezes at 0 degrees Celsius. Water boiling at 100 degrees Celsius. 1 Kelvin equals 1 degree Celsius.

Newton

[(kg)(m)]/s^2