quiz section 2.2 study helper the international system to avoid confusion, scientists established...
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Quiz Section 2.2
Study helper
The International System
• To avoid confusion, scientists established the International System of Units, or SI, in 1960 as the accepted system for measurement.
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The International System
• The SI units are related by multiples of ten.
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• Any SI unit can be converted to a smaller or larger SI unit by multiplying by a power of 10.
• The new unit is renamed by changing the prefix.
The International System
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• The meter (m) is the SI unit of length. One meter is about the length of a baseball bat.
Length
• Length is defined as the distance between two points.
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Length
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• Smaller objects can be measured in centimeters (cm) or millimeters (mm). Thelength of your textbook or pencil would be measured in centimeters.
A Long Way• To measure long distances, you use
kilometers.
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• Kilometers might be most familiar to you as the distance traveled in a car or the measure of a long-distance race.
• The course of a marathon is measured carefully so that the competitors run 42.2 km.
• When you drive from New York to Los Angeles, you cover 4,501 km.
Volume
• The amount of space an object occupies is its volume. The cubic meter (m3) is the SI unit of volume.
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Volume
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• To find the volume of a square or rectangular object, such as a brick or your textbook, measure its length, width, and height and multiply them together.
Volume by Immersion
• Not all objects have an even, regular shape.
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• When you measure the volume of an irregular object, you start with a known volume of water and drop in, or immerse, the object.
• The increase in the volume of water is equal to the volume of the object.
Mass• The mass of an object measures the amount
of matter in the object.
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• The kilogram (kg) is the SI unit for mass. • You can determine mass with a triple-
beam balance. • The balance compares an object to a known
mass. Weight and mass are not the same. Mass depends only on the amount of matter in an object.
Weight• Weight is a measurement of force.
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• The SI unit for weight is the Newton (N).
• Weight depends on gravity, which can change depending on where the object is located.
Weight
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• If you were to travel to other planets, your weight would change, even though you would still be the same size and have the same mass.
• This is because gravitational force is different on each planet.
Temperature
• The physical property of temperature is related to how hot or cold an object is.
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• Temperature is a measure of the kinetic energy, or energy of motion, of the particles that make up matter.
• Temperature is measured in SI with the Kelvin (K) scale.
Temperature• The Fahrenheit and Celsius temperature scales
are the two most common scales used on thermometers and in classroom laboratories.
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• The Kelvin scale starts at 0 K. In theory, 0 K is the coldest temperature possible in nature.
Time and Rates• Time is the interval between two events.
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• The SI unit of time is the second (s). • Time also is measured in hours (h). • A rate is the amount of change of one
measurement in a given amount of time. • One rate you are familiar with is speed,
which is the distance traveled in a given time.
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Question 1
If everyone used a different standard of measurement, there would be no way to know how one scientist’s data compared with another scientist’s data. Instead, scientists all use an agreed-upon standard of measurement known as _______.
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A. English standard of measurementB. European standard of measurementC. International system of unitsD. North American system of units
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Answer
The correct answer is C. “SI” is the International System of Units.
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Question 2If you were measuring a particular mass, for example, a big lump of cookie dough, you would measure it in terms of _______.
A. kilogramsB. litersC. newtonsD. watts
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Answer
The answer is A. A kilogram is a unit of mass.
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Question 3A spring scale can show you how much a baseball mitt weighs, but why might this figure change if you were to weigh the same object on Mars?
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Answer
Gravitational pull is different on different planets. The mass of the mitt stays the same no matter where it is, but its weight can change.