LESSON 2: Units and Reliability of Measurement, Density, and Dimensional Analysis

English Measurement System

Used primarily in the United States, units include inches, feet, pounds, and gallons

Metric System

Used in most countries around the world, units include meters, grams, liters, and Celsius. Based on powers of 10

SI System

A standardized version of the metric system used by scientists globally

Length

Distance between two points (metric base unit=meters)

Mass

Matter in an object (metric base unit=grams)

Time

How long an event lasts (metric base unit=seconds)

Temperature

How hot or cold a substance is; related to the average kinetic energy of particles (metric base unit=Kelvin)

Volume

Space occupied by a solid, liquid, or gas

Volumetric unit for Solids

cm³

Volumetric unit for Liquids and Gases

mL

1 mL is equal to

1 cm³

Density

Ratio of an object’s mass to its volume

Density utilizes units of

g/mL or g/cm³

milli

10^-3

centi

10^-2

kilo

10³

The lower the temperature…

The smaller average kinetic energy

The higher the temperature…

The greater average kinetic energy

The calculation for Kelvin is:

Tk=Tc+273.15

The calculation for Celsius is:

Tc=(Tf-32)/1.8

The calculation for Fahrenheit is:

Tf=1.8(Tc)=32