Measurement NotesChapter 2 Section 1 & 2

Precision Vs. Accuracy

• Precision- is a description of how close measurements are to each other.

• A clock with a second hand is more precise than a clock with only a minute or an hour hand.

Trials Time (s)Trial 1 34.5Trial 2 30.1Trial 3 29.2Trial 4 37.0Trial 5 36.6

Trials Time (s)Trial 1 30.1Trial 2 29.8Trial 3 29.5Trial 4 30.3Trial 5 30.0

A B

Which is more precise?

Precision Vs. Accuracy

• Accuracy- Comparing a measurement to a real, actual, or accepted value.

• A clock that is set ten minutes fast is not as accurate as one that is set at the actual time.

Trials Acceleration (m/s squared)

Trial 1 10.0Trial 2 12.5Trial 3 13.4Trial 4 9.9Trial 5 9.0

The accepted value of the acceleration due to gravity is 9.8 m/s (squared)

Which trial is the most accurate?

International System of Measurement

• In 1960 this became the accepted system for measurement.

• This is the metric system and is what is commonly used in science.

Quantity Unit Symbol

Length Meter m

Mass gram g

Temperature kelvin K

Time Second s

Electric current Ampere A

Amount of substance mole mol

Liquid Volume Liters L

Solid Volume Cubic meters

m^3

Weight newtons N

BASE UNITS

COPY CHART

International System of Measurement

• Prefix Chart– Common Prefixes• Kilograms: kg• Milliliters: mL• centimeters: cm

COPY CHART

Prefix Multiplier

kilo- 1,000

hecto- 100

deka- 10

[Unit] 1

deci- 0.1

centi- 0.01

milli- 0.001

Note Activity Time• Mnemonic Device Definition: A mnemonic device is a sentence that helps us to memorize

a string of words. For example, music students use "Every Good Boy Does Fine" to remember the order of notes on the treble clef. (E, G, B, D, F). Math students use "Please Excuse My Dear Aunt Sally" to remember the order of arithmetic operations (Parentheses, Exponent, Multiply, Divide, Add, Subtract.). But the range of usefulness extends beyond music and math. They are an invaluable resource whenever you are trying to remember something.

• Directions: Your assignment is to create a mnemonic device for the standard metric

prefixes. You can be creative in the base unit area but all the other prefixes should be accounted for in the device. Remember, the purpose of this is come up with something that will always help you remember the correct order of metric prefixes so make it

something creative or meaningful to you. SCHOOL APPROPRIATE

Ex. King Henry Died Monday Drinking Chocolate Milk i e e e e e i l c k t c n l o t a e i t l

o r i i

Kilo Hecto Deka (Base: Meter, Liter, Gram) Deci Centi Milli

Units• Length- is defined as the distance between two points

• Volume- the amount of space an object occupies

• Mass- the amount of matter in an object

• Weight- measurement of force. Weight depends on gravity and is measured in newtons (N).

• Temperature- physical property of how hot or cold something is.

• Rate- amount of change of one measurement in a give time. Example: (speed)

Data Vocabulary

• Observe- To use one or more of your senses (sight, sound, taste, touch, smell) to gain information

• Predict- Stating what you believe will happen in the future, or experiment