Section 3: Measurement Standard Measurement System • Minimizes confusion among scientists all over the world • Allows scientists to compare data and communicate with each other about the results • Metric System — developed in France in the 1790s • a.k.a. International System of Units (SI) Chapter 1 Introduction to Physical Science
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Section 3:Measurement
Standard Measurement System• Minimizes confusion among scientists all over the world• Allows scientists to compare data and communicate with each other about the
results• Metric System — developed in France in the 1790s• a.k.a. International System of Units (SI)
Chapter 1 Introduction to Physical Science
A Standard Measurement System Using SI as the standard system of measurement allows scientists to compare data and communicate with each other about their results. SI units are based on multiples of 10.
Chapter 1 Introduction to Physical Science
Metric Length
The basic unit of length in SI is the meter (m).
•Very small objects can be down to the nanometer (nm)
•Very large objects in kilometers (km)
•Common tool: metric ruler
Chapter 1 Introduction to Physical Science
Length
Chapter 1 Introduction to Physical Science
Weight
a measure of the force of gravity on an object
SI unit for weight is the Newton (N)
weight is based on the pull of gravity on your mass
weight depends on location
Chapter 1 Introduction to Physical Science
Mass
•a measure of the amount of matter and object contains
•The SI unit of mass is the kilogram (kg).
• mass does NOT change with location
•Common tool: triple beam balance
Chapter 1 Introduction to Physical Science
Mass
Chapter 1 Introduction to Physical Science
Volume
the volume of space an object takes up
SI unit of volume is the cubic meter (m3).
Chapter 1 Introduction to Physical Science
Volume
Meniscus – the curved upper surface of a liquid in a column of liquid
Chapter 1 Introduction to Physical Science
Volume
Volume of solids = LxWxH
Chapter 1 Introduction to Physical Science
Density
density is mass per unit volume
Chapter 1 Introduction to Physical Science
Density
Sink or Float?
Object sink if their density is more than that of water
Objects float if their density is less than that of water
Density of water :
Chapter 1 Introduction to Physical Science
Calculating Density Suppose that a metal object has a mass of 57 g and a volume of 21 cm3. Calculate its density.
Read and Understand
What information are you given?
Mass of metal object = 57 g
Volume of metal object = 21 cm3
Chapter 1 Introduction to Physical Science
Calculating Density Suppose that a metal object has a mass of 57 g and a volume of 21 cm3. Calculate its density.
Plan and Solve
What quantity are you trying to calculate?
The density of the metal object = __
What formula contains the given quantities and the unknown quantity?
Density = Mass/Volume
Perform the calculation.
Density = Mass/Volume = 57 g/21 cm3 = 2.7 g/cm3
Chapter 1 Introduction to Physical Science
Calculating Density Suppose that a metal object has a mass of 57 g and a volume of 21 cm3. Calculate its density.
Look Back and Check
Does your answer make sense?The answer tells you that the metal object has a density of 2.7 g/cm3. The answer makes sense because it is the same as the density of a known metal–aluminum.
Chapter 1 Introduction to Physical Science
Calculating Density
Practice Problem
What is the density of a wood block with a mass of 57 g and a volume of 125 cm3?
0.46 g/cm3
Chapter 1 Introduction to Physical Science
Calculating Density
Practice Problem
What is the density of a liquid with a mass of 45 g and a volume of 48 mL?
0.94 g/mL
Chapter 1 Introduction to Physical Science
Density
Because density is actually made up of two other measurements–mass and volume–an object’s density is expressed as a combination of two units. The density of a substance stays the same no matter how large or small a sample of the substance is.
Chapter 1 Introduction to Physical Science
Time
The second (s) is the SI unit of time.
common tool is the stopwatch
Chapter 1 Introduction to Physical Science
Temperature
Common tool – thermometer
Celsius scale – temperature scale on which water freezes at 0° and boils at 100°
Chapter 1 Introduction to Physical Science
Temperature
Kelvin scale— temperature scale on which zero is the temperature at which no more energy can be removed from matter
•Kelvin (K) is the SI unit of temperature.
• 0° Kelvin is called absolute zero
•Absolute zero is equal to -273°C
Chapter 1 Introduction to Physical Science
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