1. Standards of Measurement
Physical Science
Mr. Bostrom

2. Units and Standards
Standards – exact quantity that people agree to use for comparison
SI – standard system of measurement
All scientists use this system
Metric vs English System
Americans use the English System
Example: Feet and Inches
1970’s we tried to convert to the metric system
We failed miserably

3. Common SI Prefixes Prefix Meaning Mega (M) 1000000 Kilo (k) 1000
Hecto (h)
Deka or Deca (da) 10
Base Unit
Deci (d)
Centi (c)
Milli (m)
Micro (µ)
Nano (n)
Pico (p)

4. SI Base Units Length – Meter (m) Liter – Volume (L) Mass – Gram (g)
Time – second (s)
Electric Current – Ampere (A)
Temperature – Kelvin (K)

5. How do prefixes and base units work together
Example: Kilogram or kg
Kilo = 1000
Gram is the base unit of mass
1 Kilogram = 1000 g

6. Converting within the Metric System
Rule #1: Always remember that your base unit is 1
Rule #2: If you add a prefix onto the base unit you multiply by what the prefix represents
Example: 1 kg = 1000 g or (1000 x 1)
2 kg = 2000 g or (1000 x 2)

7. What do you do when you are not starting from or converting to your base unit?
Example: 100mm = ?km (This is where it can get tricky)
The rule of thumb is:
If you are increasing in size you move the decimal point to the left
If you are decreasing in size you move the decimal point to the right
km are bigger than mm so you move the decimal to the left

8. Sounds simple but how many decimal places do you move?
In this case 6
How did I know that
There are 4 ways to do this:
First way: divide the prefix value of the measurement you are starting with by the prefix value you want to convert to and then multiply the answer by the coefficient
Milli = .001, Kilo = 1000
( .001/1000) x 100 = (This is the final answer)
You know it was six places because you started with and to get you need to move the decimal 6 places to the left

9. Converting Contineud Second Way:
Kilo Hecto Deca Meter Deci Centi Milli
a. Find the prefix you are starting with
b. Then find the prefix you are converting to
c. Count how many prefixes you must pass to get to the
final prefix
- Always remember:
1. if you are getting larger the decimal goes to the left
2. If you are getting smaller the decimal goes to the right

10. 3rd Way
To convert from larger to smaller units, multiply the coefficient by the difference between units
To convert from smaller to larger units, divide the coefficient by the difference between units
Example: 1 million mm in a km, so divide by

11. 4th Way Factor-Label Method
Multiply your coefficient by conversion factor that equals one:
Trying to convert mm to km
1 km = mm
The conversion factor is (1 km/ mm) = 1
Example: 100 mm x (1km/ mm)
1 km/ mm = 1

12. Volume Defined as the amount of space occupied by an object
It does not just measure liquid

13. How do you calculate volume
Liquid – with a graduated cylinder
Solid (2 possible ways)
Measure the height, length, and width and then multiply the three.
Length x Width x Height
2. For a solid in which you can’t measure the length, width, and height you need to use a measuring cup or graduated cylinder
Using a graduated cylinder record a known volume of water and then drop the object into the water
Record the new volume
Take the difference between the two volumes and that is the volume of the object

14. What unit is volume recorded in?
Because you are measuring height, width, and length the unit is cm3
Volume of a liquid would be in liters
1 cm3 = 1 ml
When you combine SI units the outcome is known as a derived unit.
Examples: meters/second grams/ml

15. Density Mass per unit volume of a material
Units for density are generally g/cm3
To determine an objects density you need to divide the object’s mass by it’s volume
Example: If an object weighs 5 g and has a volume of 10 cm3 what is the object’s density
5 g / 10 cm3 = .5 g/ cm3
The density of water is 1 g/ml

16. Temperature
Generally measured in Celsius (°C) for most scientific work, however the SI unit for temperature is Kelvin (K)
How do you convert K to °C or °C to K?
To convert °C to K you need to add 273
K = °C + 273
To convert K to °C you need to subtract 273
°C = K - 273