1. Newton's First Law of Motion Grade 6 Unit 1 : Lesson #6
SI Units
Grade 6
Unit 1 : Lesson #6
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2. Newton's First Law of Motion
What you’ll learn
Vocabulary: SI
Meter
Mass
Kilogram
Kelvin
Rate
Understand the purpose of SI.
Identify the SI units of length, mass, volume, temperature, time, and rate.
Why it is important?
The SI system is used all around the world to measure quantities in the exact same as all other students do.
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3. The International System
Newton's First Law of Motion
The International System
If people in every country used different measuring systems, it would create a lot of confusion while sharing data and ideas. To avoid this complication, scientists established the International System of Units, or SI, in 1960 as the accepted system for measurement.
The SI was designed to provide a worldwide standard of physical measurement for science, industry, and commerce.
My house is just 10 yards away
Can you tell me in meters? I don’t know how much is a yard? 3 3
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4. Newton's First Law of Motion
SI unit
The SI units are related by multiples of ten. By multiplying by a power of 10, any SI unit can be converted to a larger or a smaller SI unit.
For example: To express 1 Kilogram
in terms of grams, we multiply by 1000.
The new unit is renamed by changing
the prefix.
One millionth of a meter is one micro-meter.
One kilogram is equal to one thousand grams.
SI Prefixes
Prefix
Multiplier
Giga-
1,000,000,000
Mega-
1,000,000
Kilo-
1,000
Hecto-
100
Deka- 10
[unit] 1
Deci-
0.1
Centi-
0.01
Milli-
0.001
Micro-
Nano-
SI stands for Le Syste`me
International d’Unites,
which is a French term
for International
System of units. 4 4
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5. Try this! Why was SI established?
Answer: SI was established to provide a worldwide standard of physical measurement for science, industry, and commerce.
Answer: SI was established to provide a worldwide standard of physical measurement for science, industry, and commerce. 5
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6. Newton's First Law of Motion
SI base units
Some common objects and their measurements in SI units is shown below in the table:
SI Base units
Quantity
Unit
Symbol
Length
meter m
Mass
kilogram kg
Temperature
kelvin K
Time
second s
Electric current
ampere A
Amount of substance
Mole
mol
Intensity of light
candela cd 6 6
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7. The height of the bank is 100 meters
Length
The distance between two points is defined as length. Measurement of length using different tools can describe a range of things such as the distance between any two planets, thickness of a thin wire etc.
The meter (m) is the SI unit of length. One meter is about
the size of a baseball bat.
For example: The size of a room or dimensions of a building are measured in meters.
Smaller objects can be measured in centimeters (cm) or millimeters (mm). The length of a small book or a pencil can be measured in centimeters. To measure the length of small things such as blood cells, or bacteria, scientists use micrometers.
The height of the bank is 100 meters 7
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8. Long distances
The measure long distances, such as the distance between Earth and Mars or the distance traveled by a migrating bird, we use kilometers.
Distance between New
York and Los Angeles
is 4,501 km 8
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9. Try this! Long distances are usually expressed in terms of __________
Answer: kilometers
Answer: kilometers 9
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10. Newton's First Law of Motion
Volume
Volume is the amount of space an object occupies. The SI unit of volume is cubic meter (m3).
Smaller volumes can be measured with
cubic centimeter (cm3 or cc). The volume
of a square or rectangular object, such as
a brick, or a compact disc case can be
found by measuring their length, width,
and height and multiplying them together.
A liter is a measurement of liquid volume. A cube
of 10 cm by 10 cm by 10 cm holds 1 liter (1,000 cm3)
of water. A cube 1 cm on a side holds 1 ml (1 cm3)
of water.
BRICK
Volume of a square or rectangle = length x width x height
10 cm
1 liter 10 10
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11. Newton's First Law of Motion
Volume by immersion
To measure the volume of an irregular object, we immerse the object in a known volume of water. The increase in the volume of water will be equal to the volume of the object. The volume of an irregular shaped object like a rock, or a piece of metal can be found in this way.
For example: When we add an ice cube to a nearly
full glass of water, the water in the glass overflows.
Although the volume of water did not increase at all,
the water was displaced when the ice cubes were
added. This is because the ice cube has volume due
to which it takes space. The difference in the volume
of water before and after the addition of ice cubes
will be equal to the volume of the ice cube added to
the glass of water. 11 11
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12. Try this! The cubic meter is the SI unit of what? Volume Weight Mass
Distance
Answer: A
Answer: A
Reason: The cubic meter is the SI unit of volume. 12
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13. Source: www.sks-science.com/balance-scales-p-939.html
Newton's First Law of Motion
Mass
The mass of an object measures the amount of matter in the object. The SI unit of mass is kilogram (kg).
One liter of water has a mass of 1 kg. Smaller masses
are measured in grams (g). One gram is about the mass
of a large paper clip.
Mass can be determined using a triple beam balance. The balance compares an object with a known mass. When the known standard mass of the slides on the balance is equal to the object on the pan, the beam is said to be balanced.
Source: 13 13
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14. Try this! What is the SI unit of mass? kilometer meter liter kilogram
Answer: D
Answer: D
Reason: The SI unit of mass is kilogram. 14
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15. Newton's First Law of Motion
Weight
Weight is a measurement of force. The SI unit for weight is Newton (N).
Weight is dependent on gravity, which can change depending on where the object is located.
For example: Our weight on other planets would change, even though we would still be the same size and have the same mass. This is because, the gravitational force is different on each planet. We will weigh much less in Mars and more in Jupiter. A person weighing 34 kg on Earth, which is weight
of 332 N would weigh 126 N on Mars and 782 N on Jupiter.
A spring scale measures the weight of an object by how
much a planet’s gravitational force pulls
an object. 15 15
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16. Difference between mass and weight
Newton's First Law of Motion
Difference between mass and weight
Weight and mass are not the same. The table below shows the differences between mass and weight.
Mass
Weight
Mass is the amount of matter in an object.
Weight is a measure of the force of gravity.
It is not affected by gravity.
It changes with the force of gravity.
SI Unit of mass if kilogram (kg)
SI unit of weight is Newton (N) 16 16
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17. Try this! What does weight measure?
Answer: Weight measures the force of gravity on an object.
Answer: Weight measures the force of gravity on an object. 17
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18. Newton's First Law of Motion
Temperature
The temperature is a measure of the kinetic energy, or the energy of motion, of the particles that make up matter. The physical property of temperature is related to how hot or cold an object is.
A thermometer is a device used to measure temperature. The two common scales used on thermometers are the Fahrenheit and Celsius. In SI units, temperature is measured in kelvin (K).
A 1 Kelvin difference in
temperature is the same
as 1°C difference in the
temperature. However,
the two scales do not
start at the same point as
shown. 18 18
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19. Try this! Which is a temperature scale? Volume Mass Kelvin Mercury
Answer: C
Answer: C
Reason: Kelvin is the only temperature scale among all the options. 19
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20. Newton's First Law of Motion
Time and Rates
An interval between two events is known as Time. The SI unit of time is second (s).
Long periods of time are easier to measure in hours (h)
although it is not the SI unit of time.
For example: An event duration of 3 hours, if expressed in
seconds will be 10,800 seconds.
A rate is the amount of change of one measurement with respect to time. One such familiar rate is speed, which is the distance traveled in a gives time. The SI unit of speed is meters per second (m/s) although it is commonly expressed in kilometers per hour (km/h).
A unit that is changing does not necessarily have to be an SI unit.
For example: We can measure the number of buses that pass through an intersection per hour in buses/hr. 20 20
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21. Visualization 21
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22. Newton's First Law of Motion
Summary
The international system of measurement is called SI. It is used throughout the world for communicating data.
The SI units are related by multiples of ten. By multiplying by a power of 10, any SI unit can be converted to a larger or a smaller SI unit.
The distance between two points is defines as length. The meter (m) is the SI unit of length. 22
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23. Newton's First Law of Motion
Summary
Volume is the amount of space an object occupies. The SI unit of volume is cubic meter (m3).
The mass of an object measures the amount of matter in the object. The SI unit of mass is kilogram (kg).
Weight is a measurement of force. The SI unit for weight is Newton (N). 23
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24. Newton's First Law of Motion
Summary
The temperature is a measure of the kinetic energy, or the energy of motion, of the particles that make up matter. In SI units, temperature is measured in kelvin (K).
An interval between two events is known as Time. The SI unit of time is second (s).
A rate is the amount of change of one measurement with respect to time. 24
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25. Critical thinking activity
Newton's First Law of Motion
Critical thinking activity
Why do scientists in the Unites States use SI rather than the English system (feet, pounds, pints etc) for measurements?
Notes: The SI system of measurement is understood internationally, while the English system is understood only in a limited number of countries. 25
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26. Assessment 1) How many cubic centimeters are in a cubic meter?
Newton's First Law of Motion
Assessment
1) How many cubic centimeters are in a cubic meter?
Answer: There are 1,000,000 cubic centimeters in a cubic meter.
Answer: There are 1,000,000 cubic centimeters in a cubic meter.
1 meter= 100 centimeters
1 m * 1m * 1m = 100 cm * 100 cm * 100 cm
1 m3 = 1,000,000 cm3 26 26
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27. Newton's First Law of Motion
Assessment
2) How is a seesaw similar to a pan balance.
Answer: When the weights on each side of the seesaw are equal, it is balanced. The same is the case with a pan balance.
Answer: When the weights on each side of the seesaw are equal, it is balanced. The same is the case with a pan balance. 27
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28. Newton's First Law of Motion
Assessment
3) A rectangle has a height of 1.5 m, width of 2.5 m and length of 3.2 m. What is the volume of the rectangle?
Answer: The volume of the rectangle is 12 m3
Answer: The volume of the rectangle is 12 m3
Volume=length x width x height = 1.5 x 2.5 x 3.2 = 12 28
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29. Newton's First Law of Motion
Assessment
4) How would you change a measurement in centimeter to kilometer?
Answer: Divide by 100,000
Answer: Divide by 100,000
1 kilometer = 1000 meter
1 meter = 100 centimeter
Therefore 1 kilometer = 1000 x 100= 100,000 centimeter. 29 29
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30. Newton's First Law of Motion
Assessment
5) Which SI unit replaces the pound?
Answer: Newton
Answer: Newton
Reason: Pound is used to measure weight. The SI unit of weight is Newton. 30
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31. Assessment 6) Express 3 hours and 9 minutes in SI units.
Newton's First Law of Motion
Assessment
6) Express 3 hours and 9 minutes in SI units.
Answer: seconds (s)
Answer: The SI unit of time is second (S)
1 hour = 60 minutes and 1 minute=60 seconds
1 hour = 60 x 60 =3600 seconds
3 hours = 3 x 3600 = seconds
9 minutes = 9 x 60 = 540 seconds
Total = = seconds. 31 31
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32. Assessment 7) How can different units of measure cause confusion?
Newton's First Law of Motion
Assessment
7) How can different units of measure cause confusion?
Answer: A person might express temperature in Fahrenheit degrees, while another person might express it in Celsius degrees. When these two persons interact it could cause confusion.
Answer: A person might express temperature in Fahrenheit degrees, while another person might express it in Celsius degrees. When these two persons interact it could cause confusion. 32 32
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33. Newton's First Law of Motion
Assessment
8) List the following in order from smallest to largest : 10 m, 900 cm, 9 km, 100 mm
Answer: 100 mm, 900 cm, 10 m, 9 km
Answer: 100 mm, 9000 cm, 10 m, 9 km
Reason: 900 cm = 9 m 33 33
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34. Newton's First Law of Motion
Assessment
9) Match the following quantities with their corresponding SI Units
Temperature kilogram
Volume Kelvin
Mass meter
Length cubic meter
Weight second
Time Newton 34 34
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35. Newton's First Law of Motion
Assessment
10) Look at the data in the table below and answer the following questions.
Question 1 : According to the table, express Samuel’s weight in kilograms for the three months?
Answer: kg, kg, 41 kg
Question 2: Who weighs the heaviest during the month of March?
Answer: Samuel
Student weights: Jan – Mar 2009
Student
Jan
Feb
Mar
Geisha
38.2 kg
39 kg
38.7 kg
Samuel
42,450 g
42,400 g
41 kg
Lisa
36 kg
36.4 kg
37 kg
Rachel
40,456 g
40,000 g
40,200g
Answer: kg, kg, 41 kg
Samuel 35 35
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36. Practice
A block of wood is 0.3 m by 0.2 m by 0.1 m. Find its dimensions in centimeters. What is the volume in cubic centimeters?
Notes: 0.3 meters = 0.3 x 100 = 30 cm
0.2 meters = 0.2 x 1000= 20 cm
0.1 meters= 0.1 x 1000=10 cm
Volume = 30 cm x 20 cm x 10 cm = 6000 cm3 36 36

37. Thank You! 37
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