using si units measurement standard an exact quantity that people agree to use for comparison. *...
TRANSCRIPT
Using SI Units
Measurement Standard•An exact quantity that people agree to use for comparison.
* helps you get the same answer as other
people
What was used as the earliest measurement standards?
•Body Parts* The question then, is
WHO’S body parts?
The KING’S or QUEEN’S
• Is your hand or a body part a
good standard of measurement?
* no
* people’s hands are not the
same size
* get different answers
•In order for any measurement to MAKE SENSE; two things must be included.
1.) a number2.) a unit
•Every type of measurement has a base or central unit.
* meter (distance or length)
* liter (volume)
* gram (mass)
* second (time)
•Adding a prefix to a base (central) unit, you can create a whole new unit to measure any object.
Prefixes Used When Measuring:
• Large Objects
kilo = 103
hecto = 102
deka = 101
• Small Objects
deci = 10-1
centi = 10-2
milli = 10-3
Measurements that can be made
• Length
• Mass
• Temperature
• Time
• Area
• Volume
• Density
• Weight
Length• The distance between two
points.• Base (central) units of length
* (US) FOOT [ft]
* (SI) METER [m]
Length• Length of an object or the
distance between two points is measured using a METERSTICK.
Mass• “A body of coherent matter.”
* a collection of stuff joined to form an object
• Base (central) units of mass* (US) SLUG [slug]* (SI) KILOGRAM [kg]
sometimes gram [g]
Mass•Mass is measured using a BALANCE.
Temperature
•Measurement of how hot or cold something is.
Temperature• Base (central) units of
temperature
* (US) FAHRENHEIT [oF]
* (SI) CELCIUS [oC]
> (SI) KELVIN [K]
* this is an absolute scale
Temperature• Temperature is measured
using a THERMOMETER.
Absolute Zero• The coldest possible
temperature.* temperature where ALL
motion stops* 0 Kelvin * found by the formula:
K = oC + 273.16
Time• Interval between two
events.•Base (central) units of
time* (US) SECOND [s]* (SI) SECOND [s]
Time•Time can be measured using a CLOCK or a CALENDAR.
Derived Units•Obtained by combining multiple units of measurement.
Area
• The amount of surface
included in a set of boundaries.
• Found by the formula:
* Area = length x width
Area•What is the difference between length and width?
•DIRECTION
Area
• Base units of area
* (US) FEET SQUARED [ft2]
* (SI) METERS SQUARED[m2]
Volume• The amount of space an object
occupies.• Easy with liquids & gases,
harder with solids
* for a solid you may need the formula:
volume = l x w x h
Volume• For a liquid or a gas all you
need is a devise that is designed to measure volume.
* a beaker, a flaskor a graduated
cylinder
Volume• Base (central) units of volume
* (US) GALLON [gal]
* (SI) LITER [L]
sometimes centimeters cubed [cm3]
Volume
•1 milliliter equals
1 centimeter cubed.
* 1 mL = 1 cm3
Density• The measurement of how
thick, compact and solid an object is.
• Relationship between the mass & volume of an object
Density
•Found by the formula:
* Density = mass ÷ volume
• Expressed in g/L or g/cm3
* a mass unit / a volume unit
Weight• Measurement of the force of
gravity pulling on the mass of an object.
• Changes as gravity changes.• Base units of weight
* (US) POUND [lb]* (SI) NEWTON [N]
Weight•Weight is measured using a SPRING SCALE.
•MASS and WEIGHT are NOT the same thing!
Physical Properties• Characteristics of a substance that can be
used to identify it.• Color• Shape• Texture
• State of matter• Size
• All measurements(changing a physical property does NOT change the substance)