SCIENCE SKILL MEASUREMENT TOPIC METRIC CONVERSION BRIEF HISTORY

SCIENCE SKILL: MEASUREMENT TOPIC: METRIC CONVERSION

BRIEF HISTORY OF MEASUREMENT When people first began to take measurements, they used parts of their bodies as measuring devices for example their fingers, hands and feet Let’s take some measurement using the traditional method of body measurement

USING BODY MEASUREMENTS Use traditional body measurements to obtain lengths from objects around the room: Width of sink in digits Perimeter of room in fathoms length of table in cubits Height of whiteboard in hands

BRIEF HISTORY OF MEASUREMENT When people first began to take measurements, they used parts of their bodies as measuring devices for example their fingers, hands and feet What’s the problem with this? It lacks consistency because peoples’ bodies are of varying sizes.

CURRENT SYSTEMS OF MEASUREMENT Two systems developed over time that are widely used today: The metric system developed in France, used all over the world, including Canada Based on multiples of 10; easy to use and convert between units The imperial system Used predominantly in the USA; Used in Canada for trades More difficult than the metric system: Primary unit is the foot, which is subdivided into 12 equal parts called inches. Another unit is the yard, which is 3 feet long. Longer distances are measured in miles; a mile is 5280 feet long.

METRIC SYSTEM Based on multiples of 10 The basic unit of length is the metre Larger units are based on metres multiplied by 10, 1000 etc Smaller units are based on metres divided by 10, 1000 etc Each multiple has its own prefix (syllable joined to the beginning of a word) Same prefixes used for most types of metric measurement: length, mass, volume, area, energy

COMMON METRIC PREFIXES Prefix Symbol Relationship to the base unit giga- G 109 = 1 000 000 mega- M 106 = 1 000 kilo- k 103 = 1 000 hecto- h 102 = 100 deca- da 101 = 10 -- -- 100 = 1 deci- d centi- c milli- m micronano- n

EXAMPLE #1: A student measures 459 ml of water. Express this value in L. Prefix Symbol Relationship to the base unit giga- G 109 = 1 000 000 mega- M 106 = 1 000 kilo- k 103 = 1 000 hecto- h 102 = 100 deca- da 101 = 10 -- -- 100 = 1 deci- d centi- c milli- m micronano- n

EXAMPLE #2 : A student needs to measure 0. 4 kg of salt. Express this mass in g. Prefix Symbol Relationship to the base unit giga- G 109 = 1 000 000 mega- M 106 = 1 000 kilo- k 103 = 1 000 hecto- h 102 = 100 deca- da 101 = 10 -- -- 100 = 1 deci- d centi- c milli- m micronano- n

PRACTICE QUESTIONS Prefix Symbol Relationship to the base unit giga- G 109 = 1 000 000 mega- M 106 = 1 000 kilo- k 103 = 1 000 hecto- h 102 = 100 deca- da 101 = 10 -- -- 100 = 1 deci- d centi- c milli- m micronano- n Complete the following question, showing your work. Be sure to include the unit in your answer. 1. The amount of energy used by an appliance is 250 W. Express this in k. W 2. The volume of water that is needed to fill a holding tank is 357 L. Express this in m. L. 3. The atomic radius of an atom of an element is 0. 112 mm. Express this in m.

PRACTICE QUESTIONS - SOLUTIONS Prefix Symbol Relationship to the base unit giga- G 109 = 1 000 000 mega- M 106 = 1 000 kilo- k 103 = 1 000 hecto- h 102 = 100 deca- da 101 = 10 -- -- 100 = 1 deci- d centi- c milli- m micronano- n

NEXT CLASS Length – base unit : metre (m) Mass – base unit : gram (g) Volume – base unit : Litre (L) Energy – base unit : Watt (W)