measurement systems english system (usa) –based on feet, pounds, gallons –complex metric (si)...
DESCRIPTION
a decimal system of measurement based on 10 Prefixes of SI used in this class: Kilo= 1000 Deci= 1/10 or 0.1 Centi= 1/100 or.01 milli= 1/1000 or.001TRANSCRIPT
Measurement Systems• English System (USA)
– based on feet, pounds, gallons– Complex
•Metric (SI) system (everyone else)– Simpler– Based on powers of 10
a decimal system of measurement based on 10
Prefixes of SI used in this class:Kilo= 1000Deci= 1/10 or 0.1Centi= 1/100 or .01milli= 1/1000 or .001
Measurements• Must have both a number and
a unit: – Ex: 4m
• Size of object determines size of unit used
Length • Distance between 2 points
1km = 1000m1m = 100cm1cm = 10mm
Mass•Mass: amount of matter in an
object– Measured with a balance– Units = g or kg
Volume•Volume: Amount of space taken
up by an object.
• Units = liters (L), milliliters (mL), cm3
Measuring Volume 3 Methods:1. Volume of Regular solids
(cubes, rectangles). V = length x width x height
Volume = 5 cm x 5 cm x 5 cm
= 125 cm3
5 cm
5 cm
5 cm
2.Volume of a liquid
•Pour and measure– Use graduated cylinders
Reading a Graduated cylinder
Record value at bottomof meniscus
In this case 52.8 ml
Measuring Volume 3. Irregular solid (rock) by water
Displacement
• Volume of water displaced = volume of object
Volume by water displacement
Density
Density•Density = Mass/Volume
• Units = g/ml or g/cm3
M
D V
Buoyancy• Ability of a fluid to exert an
upward force on an object placed in it
Density & Buoyancy• If object is less dense than the
fluid it’s in, it floats
• If object is more dense than the fluid it’s in, it sinks
• Density of water = 1.0 g/mL
Temperature• Measured with a thermometer
• SI base unit is Kelvin
Kelvin vs. Celsius ScaleCelsius Scale: •Water freezes
at 0° C
•Water boils at 100° C
Kelvin Scale• 0 K is called absolute zero. • At 0 K all particles stop moving.
Kelvin/Celsius Conversion
K = °C + 273
Graphing Data
Why use Graphs?• provides easy method of organizing
data (picture)3types of graphs
1. Bar: used for comparing data2. Circle: shows how parts relates to a
whole 3. Line: shows changes that occur
between related variables
Bar Graph
Circle Graphs• Parts always add up to 100%
Line Graphs• Most scientific graphs are line
graphs• Lines can be straight
Line graphs• Lines can also be curved