Metric System The metric system is based on a base unit that corresponds to a certain kind of measurement Length = meter Volume = liter Weight (Mass) = gram Prefixes plus base units make up the metric system –Example: Centi + meter = Centimeter Kilo + liter = Kiloliter

Metric System These prefixes are based on powers of 10. What does this mean? –From each prefix every “step” is either: 10 times larger or 10 times smaller –For example Centimeters are 10 times larger than millimeters 1 centimeter = 10 millimeters kilo hectodeca Base Units meter gram liter deci centimilli

Metric System For each “step” to right, you are multiplying by 10 For example, let’s go from a base unit to centi 1 liter = 10 deciliters = 100 centiliters 2 grams = 20 decigrams = 200 centigrams kilo hectodeca meter liter gram deci centimilli ( 1 x 10 = 10) = (10 x 10 = 100) (2 x 10 = 20) = (20 x 10 = 200)

Metric System An easy way to move within the metric system is by moving the decimal point one place for each “step” desired Example: change meters to centimeters 1 meter = 10 decimeters = 100 centimeters or 1.00 meter = 10.0 decimeters = 100. centimeters kilo hectodeca meter liter gram deci centimilli

Metric System Now let’s try our previous example from meters to kilometers: meters = decameters = hectometers = kilometers So for every “step” from the base unit to kilo, we moved the decimal 1 place to the left (the same direction as in the diagram below) kilo hectodeca meter liter gram deci centimilli

Metric System If you move to the left in the diagram, move the decimal to the left If you move to the right in the diagram, move the decimal to the right kilo hectodeca meter liter gram deci centimilli

Metric System Summary –Base units in the metric system are meter, liter, gram –Metric system is based on powers of 10 –For conversions within the metric system, each “step” is 1 decimal place to the right or left –Using the diagram below, converting to the right, moves the decimal to the right and vice versa kilo hectodeca meter liter gram deci centimilli

Measuring Distance (Length): Length is the distance between two points. SI base unit for length is m We need to use different unites sometimes: – cm for things like a pencil – Km for long distances like between RAK and Dubai. –1m = 100 cm –1Km = 1000 m –1cm = 10 mm –1dm = 10 cm

Measuring Volume Volume: the amount of space occupied by an object. You’ll learn how to measure the volume of: 1. Regular solids, like a cube. 2.Liquids. 3. Irregular solids, like a pencil or a crown

1.Volume of regular solids: Ex: a cube V = l x w x h = 5 cm x 5 cm x 5 cm = 125 cm 3 Where cm 3 is a volume unit.

Measuring Mass Mass : How much matter in an object. Units: kg, g, mg, …. 1 kg = 1000 g 1g = 1000 mg Example: how many kilograms are in 6430 mg? 6.43 kg

Density : is the mass per unit volume. Density = mass volume What is the density of an object having a mass of 10g and a volume of 2 cm 3 ? Density = 10g = 5 g/cm 3 2 cm 3 The unit of density is g/cm 3

Measuring Time and Temperature Time: the interval between two events. –The unit of time is the second Temperature: measured with a thermometer and measured in Celsius or Kelvin. Celsius ranges from 0 (freezing) to 100 (boiling). The Kelvin scale begins at absolute zero, or 0 K. To convert to Kelvin you add 273 degrees to the Celsius reading. Freezing in Kelvin is 273 K, boiling is 373 K.

Scientific numbers use powers of 10

No decimal point Zeros are not significant ! 2 sig figs Decimal Point All digits including zeros to the left of The decimal are significant. 6 sig figs

Zeros between Non zeros are significant All figures are Significant 4 sig figs Zero to the Right of the Decimal are significant All figures are Significant 5 sig figs

Zeros to the right of The decimal with no Non zero values Before the decimal Are not significant 3 sig figs Zeros to the right of the decimal And to the right of non zero values Are significant 5 sig figs