#### Transcript Measurement

Measurement Measurement • Measurements have 2 parts: – 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 Kilo hecto deka base: deci centi milli Symbol k h da d c m multiplier 1,000 100 10 1 0.1 0.01 0.001 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 1. Write out the abbreviations in a horizontal row: KHDUDCM 2. Find the location of the original unit, then count the number of jumps and direction to the new unit 3. Re-write the number, then hold the pencil on the decimal point. 4. Move your pencil, making “egg crates”, the number of jumps in the correct direction- then fill in the empy crates with ZEROS 5. Re-write your final answer, including number and unit Let’s try some! Convert: 12 gram to kilograms 87.25 hL to cL 5.22 seconds to milliseconds 99.99 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 Volume= the amount of space something takes up Solid Measurement • The BASE unit = cm3 • Use a formula to calculate for regular shapes • For irregular shapes use Water Displacement Method Liquid Measurement • The BASE unit = Liter • Use a GRADUATED CYLINDER to measure Volume Direct Measurement • Use a ruler to measure and plug into formula • Example: Volume of a cube = length x width x height Indirect Measurement • Water displacement method 1. Fill a graduated cylinder with water- record volume 2. Carefully add objectrecord new volume of water 3. 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 (0.30400823) have a NEGATIVE exponent • #’s greater than 1 have a POSITIVE exponent Try Some: • Expand: • 4.2 x 104 • 3.359 x 10 -6 • 7.8112 x 108 Try Some More… • Write in scientific notation: • • • • 870 0.0000789 0.245 75000