Units of Measurement

1-2

►SI Units and symbols

►Length

distance between two (2) points

►SI unit meter (m)

100cm = 10dm = 1m

*the unit used depends on size of the item being measured*

►Pencil = cm

►Classroom = m

►Long Distances = km (1000 meters)

►1km = about 10 football fields long

►Convert = Change

►Rules of conversion

A measurement consists of two (2) points:

► Number AND Unit label

To convert from LARGER to SMALLER units- Multiply

To convert from SMALLER to LARGER units Divide

(Use step chart)

►METER STICK = ►10 dm =100 cm =1000 mm

1 km = 1000m

Volume

►amount of space occupied by an object ►V = L x W x H

(cm3) (m3)

Derived Units

Units obtained by combining SI Units

Converting M to cm p40

►How many cm are in 1.98 meters?

What is known?

►1m = 100cm

►Larger to smaller = multiply

►1.98 X 100 = 198

►198 cm

Practice Problem How many centimeters are in 253.8 km? HINT: Change km to m; then m to cm. 253.8km = 25,380,000cm

Practice problem 2 A bookshelf is 75 cm wide. How many decimeters is this? How many meters? 75 cm = 7.5 dm 75 cm = 0.75 m

Volume of liquid:

►container that holds the amount of liquid Liters

Milliliters ►(medicine = cm3)

1L = same volume as a cubic decimeter (dm3) ►1dm = 10 cm

►1L = 1000mL

►1dm3 = 1000 cm3

►1L = 1dm3

►1mL = 1cm3

►1L = 1000cm3

►MASS =

Measurement of the matter in an object use a balance

► SI Unit of mass = kg ►Small objects = mass = grams (g) or mg

► 1kg = 1000g

►Density = mass per unit of volume of material ►D = m/v

►Time and Temp

Time = interval between 2 events (second)

stopwatch/clock

► Temp = how hot or cold something is thermometer – Celsius scale

► Freezing = 0 deg C

► Boiling = 100 deg C

► Human = 37deg C

► Room temp = 20 – 25 deg C

► SI units of temp = Kelvin (K)

► 0K = Zero on the Kelvin Scale Absolute zero (coldest possible temp (-273 deg C)

(273 degrees below the freezing point of water) ► Kelvin temp add 273 to Celsius

► Water freezes at 273 deg K

► Boils at 373 deg K

►Graphs

Graph: Visual display of information

Line Graph: Show trends or how data changes

Bar Graph: Comparing info

Circle Graph: Show a fixed quantity broken into pieces