Transcript International System of Measurement

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? (think of the scientific method)
– Step 6 of the scientific method
– Results of an experiment must be able to be
replicated by other scientist
2. The metric/SI system is also easier to use.
– Why?
– The system is based on or
of 10
– 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:
Height
Length
3. Measure the length of this line in millimeters:
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?
AREA
• What is the area of an object?
• L x W = meters squared
5 cm
= 50 cm2
10 cm
Temperature
SI base unit =
degrees Celsius
Instrument used to measure:
Thermometer
Therm =
heat
Let’s do a comparison:
CELSIUS
100
-------37
-------22
------0
--------
VS
FAHRENHEIT
WATER BOILS
BODY TEMP
ROOM TEMP
WATER FREEZES
° C x 9/5 + 32 = °F
(°F - 32) x 5/9 = °C
212
---------98.6
---------70
32
----------
BOILING
37 C
22
BODY TEMP
ROOM TEMP
FREEZING
98.6 C
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
Flask
Graduated Cylinder
Beaker
• 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
Change unit to cm3
Answer: 2 cm3
2ml
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.
Mass: 68 Kg
Weight: 147 pounds
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
Feathers
1 Kg of
Stones
More or less dense?????