Types of quantitative observations

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.

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 method Results of an experiment must be able to be replicated by other scientist Metric system is also easier to used. Why? Based on multiples and divisions of 10

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.

Length: distance between 2 points SI base unit = meter Instrument used to measure length? metric ruler or meter stick Divisions of a meter = dm, cm, mm Multiples of a meter = Km, Hm, Dm

Let’s practice!!!!!!!

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: Height Length

Conversions -Changing from one unit to another. -Uses prefixes to describe divisions and multiples of a base unit. 1000 100 10 1 .1 .01 .001 Kilo Hecto Deca BASE deci centi milli UNIT King Henry died----gulp----drinking chocolate milk

Metric –vs- English Conversions Kilo Hecto Deca BASE deci centi milli UNIT Easier: 10 Kilometers = how many meters? 500 centimeters = how many meters? Harder: 10 miles = how many inches? 10 Km move decimal 3 places to right = 10000 meters 500 cm move decimal 2 places to left = 5. meters 10 miles x 5280 feet x 12 inches = 6336 inches 1 mile 1 foot

AREA What is the area of an object? = 50 cm2 L x W = meters squared

Solid volume: How much space an object occupies LxWxH = m3

Temperature SI base unit = degrees Celsius Instrument used to measure: Thermometer Therm = heat

Let’s do a comparison: ° C x 9/5 + 32 = °F (°F - 32) x 5/9 = °C CELSIUS VS FAHRENHEIT -------- WATER BOILS ---------- -------- BODY TEMP ---------- ------- ROOM TEMP 70 -------- WATER FREEZES ---------- 212 100 37 98.6 22 32 ° C  x  9/5 + 32 = °F (°F  -  32)  x  5/9 = °C

BOILING BODY TEMP 37 C 98.6 C ROOM TEMP 22 FREEZING

Volume How much space an object occupies. Two types of volume: Liquid and solid Liquid volume: SI base unit = liter (Kl, Hl, Dl, l, dl, cl, ml)

Instrument used to measure liquid volume? Graduated Cylinder Beaker Flask Graduated Cylinder

Read the bottom of the meniscus. = 43 ml

Solid Volume: Amount of space an object occupies. Length x Width x Height SI label: m3 or cm3

Not all solids have a regular shape!! Sometimes the length , width and height can not be determined Regularly shaped Irregularly shaped

Solid volume of a irregular shaped object Use water displacement to determine volume

Water Displacement Record volume of water in graduated cylinder. 7ml Add object Record volume of water after object is added. 9ml The difference is the volume of the object 2ml Change unit to cm3 Answer: 2 cm3

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

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.

Top of mountain Sea level Mass stayed constant Mass: 68 Kg Weight: 147 pounds Mass stayed constant Weight decreased due to a lesser pull of gravity. Top of mountain Mass: 68 Kg Weight: 150 pounds Sea level

Density: The mass of an object per unit volume. mass / volume = g/L (liquid density) g/m3 (solid density)

Density Determination 1 Kg of Stones 1 Kg of Feathers Mass of stones = 1 Kg Volume of stones = 10 m3 Density = mass = 1 Kg = 2 volume .5m3 Mass of feathers = 1 Kg Volume of feathers = 100 m3 Density = mass = 1 Kg = .001 volume 1000 m3

Less dense than the liquid More dense than the liquid More or less dense????? Less dense than the liquid More dense than the liquid