2 International System of Units 1. Known as SI units (System International)Official name of the metric system.Is an “universal system of measurement” in the scientific world.What does “Universal” mean?Used by all scientist worldwide regardless of their language.
3 Why does science need an universal system of measurement Why does science need an universal system of measurement? (think of the scientific method)Step 6 of the scientific methodResults of an experiment must be able to be replicated by other scientistMetric system is also easier to used.Why?Based on multiples and divisions of 10
4 2. The metric/SI system is also easier to use. Why?You only need to move a decimal point to the left or to the right.
5 Length: distance between 2 points SI base unit =meterInstrument used to measure length?metric ruler or meter stickDivisions of a meter =dm, cm, mmMultiples of a meter =Km, Hm, Dm
7 Answers: 1. Measure the length of this rectangle in centimeters: 2. Measure the height of this rectangle in centimeters:3. Measure the length of this line in millimeters:HeightLength
8 Conversions-Changing from one unit to another.-Uses prefixes to describe divisions and multiplesof a base unit.Kilo Hecto Deca BASE deci centi milli UNITKing Henry died----gulp----drinking chocolate milk
9 Metric –vs- English Conversions Kilo Hecto Deca BASE deci centi milliUNITEasier:10 Kilometers = how many meters?500 centimeters = how many meters?Harder:10 miles = how many inches?10 Km move decimal 3 places to right = meters500 cm move decimal 2 places to left = 5. meters10 miles x 5280 feet x 12 inches = inches1 mile foot
10 AREA What is the area of an object? = 50 cm2 L x W = meters squared
11 Solid volume:How much space an object occupiesLxWxH = m3
12 Temperature SI base unit = degrees Celsius Instrument used to measure: ThermometerTherm =heat
13 Let’s do a comparison: ° C x 9/5 + 32 = °F (°F - 32) x 5/9 = °C CELSIUS VS FAHRENHEITWATER BOILSBODY TEMPROOM TEMPWATER FREEZES2121003798.62232° C x 9/ = °F(°F - 32) x 5/9 = °C
18 Solid Volume: Amount of space an object occupies. Length x Width x HeightSI label:m3 or cm3
19 Not all solids have a regular shape!! Sometimes the length , width and height can not be determinedRegularly shaped Irregularly shaped
20 Solid volume of a irregular shaped object Use water displacementto determine volume
21 Water Displacement Record volume of water in graduated cylinder. 7ml Add objectRecord volume of water after object is added. 9mlThe difference is the volume of the object 2mlChange unit to cm3Answer: 2 cm3
22 Mass The amount of matter in an object. SI unit: -grams (Kg, Hg, Dg, g, dg, cg, mg)Instrument or tool to used to determine mass?-Balance
23 Mass is different than weight Mass is a constant value, it is not influenced by the pull of gravity. Weight is based upon the pull of gravity. The pull of gravity varies based on an objects distance from the center of the Earth.
24 Top of mountain Sea level Mass stayed constant Mass: 68 KgWeight: 147 poundsMass stayed constantWeight decreased due to a lesser pull of gravity.Top of mountainMass: 68 KgWeight: 150 poundsSea level
25 Density: The mass of an object per unit volume. mass / volume = g/L (liquid density)g/m3 (solid density)
26 Density Determination 1 Kg of Stones1 Kg of FeathersMass of stones = 1 KgVolume of stones = 10 m3Density = mass = Kg = 2volume m3Mass of feathers = 1 KgVolume of feathers = 100 m3Density = mass = Kg = .001volume m3
27 Less dense than the liquid More dense than the liquid More or less dense?????Less dense than the liquidMore dense than the liquid