Measurement
●
●
I can identify SI units of measurement
I can explain scientific notation
Measurement
● Used in scientific
observations
● Includes a number AND a unit
● Science uses a standard
system of units called SI units
(base 10)
Length
● SI unit is the meter (m)
○ Divided into 100 equal parts called centimeters (cm);
1cm= 1/100 m
○ 10 millimeters (mm) in 1 cm
○ Longer distances measured in kilometer (km); 1000
m= 1 km
Mass
● The amount of matter in an object
○ Depends on the number and types of atoms that
makeup the object
● Mass of an object is the same no matter where in the
universe the object is
● SI unit for mass is gram (g)
Weight
● The measure of the gravitational force on an object
● Usually measured on a scale
● Can vary with location
○ ex.) gravitational force on the moon is 1/6 less than Earth
● Weight is a force and SI unit for force is a newton (N)
○ A 2 liter soft drink with a mass of 2 kg weighs about 20
newtons on Earth
Area & Volume
● Area- the amount of surface included within a set of
boundaries
○ Expressed in square meters (m2)
● Volume- the amount of space occupied by an object
○ Basic SI unit for a solid is the cubic meter (m3)
● Fluid volumes are milliliters (mL) or liters (L)
○ 1 cm3 = 1 mL
Area & Volume
Density
● The amount of matter that
occupies a given space
● Calculated by dividing the
mass by the volume
● Can be expressed as g/cm3,
g/mL, or kg/m3
Time
● The interval between 2 events
● SI unit is the second
● Usually measured with a watch or
clock
● The atomic clock provides the most
precise measurement, known as
UTC
Temperature
●
●
●
A measure of the average kinetic energy of particles
○ A mass made up of particles that vibrate quickly generally has a
higher temperature than a mass whose particles vibrate slowly
Measured in degrees by a thermometer
○ Scientists usually use celsius
SI unit is kelvin (K)
○ The coldest possible temperature, absolute zero, is 0 K or -273 C
○ add 273 to Celsius temp to get Kelvin
Temperature
● Try it!
○ Convert the temperature 49 C to kelvin
■ 322 K
Scientific Notation
●
●
●
When a measurements is very large or very small, scientists abbreviate
with scientific notation.
Number is expressed as a value between 1 and 10 multiplied by a power of
10
○ ex.) 5.76 x 106 ; 2.98 x 10-3
The power of 10 is the number of places the decimal must be shifted so
that only a single digit remains to the left of the decimal point
○ ex.) 5.76 x 106 = 5,760,000 ; 2.98 x 10-3 = 0.00298
Scientific Notation
●
●
If the decimal point must be shifted to the left, the number is positive
○ The number of grains of sand on Earth has been estimated to be
4,000,000,000,000,000,000,000
○ In scientific notation, this number is 4x1021
If the decimal must be shifted to the right, the exponent is negative
○ The diameter of an atom, 0.0000000001m, is written as 1x10-10
Scientific Notation
●
Try it!
○ Write the speed of light, 299,792,458 m/s in scientific notation
■ 2.99792458 x 108
○ Write the mass of an electron 0.000 000 000 000 000 000 000 000
000 000 911 kg in scientific notation
■ 9.11 x 10-31