# Measurement.

## Presentation on theme: "Measurement."— Presentation transcript:

Measurement

Measurement Measurements have 2 parts: Example: 5cm
A number A unit Example: 5cm Scientists (and we will) use the SI system Système International d’unités

The SI units = METRIC There are only 3 countries in the whole world using the ENGLISH SYSTEM of measurement Liberia Myanmar (formerly Burma) THE UNITED STATES of AMERICA Why is the metric system so much easier? Most countries use it It is based on powers of 10

Units There is always a BASE unit for every measurement
There can be prefixes added to the base to make it larger or smaller Example: millisecond, kilogram

Base Units Length = meter (m) Mass = gram (g)
Volume = liter (L) or cubic centimeters (cm3) Time = second (s) ** Prefixes multiply the BASE unit by a value of 10 **

PREFIX Symbol multiplier
Kilo k 1,000 hecto h 100 deka da 10 base: 1 deci d 0.1 centi c milli m

King Henry Died Unfortunately Drinking Chocolate Milk

Unit Conversions The metric system is so useful because we can convert from one unit to another EASILY Write out the abbreviations in a horizontal row: K H D U D C M Find the location of the original unit, then count the number of jumps and direction to the new unit Re-write the number, then hold the pencil on the decimal point. Move your pencil, making “egg crates”, the number of jumps in the correct direction- then fill in the empy crates with ZEROS Re-write your final answer, including number and unit

Let’s try some! Convert: 12 gram to kilograms hL to cL 5.22 seconds to milliseconds dm to cm How many centiliters are in 1 kiloliter?

Length Length = distance from one point to another
Length is measured with a METRIC RULER The BASE unit = meter Examples: centimeter (cm), millimeter (mm), decimeter (dm)

Mass Mass= the amount of matter in an object
Mass is measured with a balance The BASE unit = gram Examples: kilogram (kg), milligram (mg)

Volume= the amount of space something takes up
Solid Measurement Liquid Measurement The BASE unit = cm3 Use a formula to calculate for regular shapes For irregular shapes use Water Displacement Method The BASE unit = Liter Use a GRADUATED CYLINDER to measure

Volume Direct Measurement Indirect Measurement
Use a ruler to measure and plug into formula Example: Volume of a cube = length x width x height Water displacement method Fill a graduated cylinder with water- record volume Carefully add object- record new volume of water Subtract old volume from new volume = volume of object

In order for a measurement to be reliable…
It needs to be both ACCURATE and PRECISE Accuracy = EXACT Precision = multiple measurements close to each other

Scientific Notation Makes using large numbers easier
Write a number times a power of 10 Example: 3.0 x 108 = 300,000,000 Number must be between 1 and 10 Always there The NUMBER of places and DIRECTION the decimal is moved

Scientific Notation #’s less than 1 ( ) have a NEGATIVE exponent #’s greater than 1 have a POSITIVE exponent

Try Some: Expand: 4.2 x 104 3.359 x 10 -6 x 108

Try Some More… Write in scientific notation: 870 0.245 75000