3rd Grade Measurement

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3rd Grade Measurement
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Third Grade Standards for Measurement

• 4.M.1      Demonstrate an understanding of such
  attributes as length, area, weight, and volume,
  and select the appropriate type of unit for
  measuring each attribute.
• 4.M.2      Carry out simple unit conversions
  within a system of measurement, e.g., hours to
  minutes, cents to dollars, yards to feet or
  inches, etc.
• 4.M.3      Identify time to the minute on analog
  and digital clocks using a.m. and p.m. Compute
  elapsed time using a clock (e.g., hours and
  minutes since) and using a calendar (e.g., days
  since).
• 4.M.4      Estimate and find area and perimeter
  of a rectangle, triangle, or irregular shape
  using diagrams, models, and grids or by
  measuring.
• 4.M.5      Identify and use appropriate metric
  and English units and tools (e.g., ruler, angle
  ruler, graduated cylinder, thermometer) to
  estimate, measure, and solve problems involving
  length, area, volume, weight, time, angle size,
  and temperature.

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Why Do We Measure?

• Measuring things helps us answer the questions
• How big?
• How long?
• How much?

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What Do We Measure?

• We measure
• Time
• Length perimeter
• Area
• Capacity volume
• Weight

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Every Measurement Has Units

• A measurement always has units. For example, we
  measure time in millennia, centuries, decades,
  years, days, weeks, and hours. Without the unit,
  we dont know how much time has passed. The
  units that go with our measurements tell us what
  we are measuring and how much we have.

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Measuring Time

• We measure time using clocks and calendars.

Calendars tell us what day each date is on and
can help us keep track of how many days have gone
by.
The big, dark hand tells us the minute. The
small, dark hand tells us the hour, and the long,
gold hand tells us the second.
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Time Units
Seconds The smallest unit of time on a
clock Minutes There are 60 seconds in one
minute. Hours There are 60 minutes in one
hour. Days There are 24 hours in one
day. Weeks There are 7 days in one
week. Months The number of days and weeks in a
month is different for each month. Years There
are 365 ¼ days in one year. Decades There are 10
years in one decade. Centuries There are 100
years or 10 decades in one century. Millennia The
re are 1000 years, 100 decades, or 10 centuries
in one millenium.
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Measuring Length
Length is the size of a straight line, distance,
or straight edge on an object.

• We measure length with a ruler. Each ruler is
  divided into units. When using a ruler, line up
  the edge of the ruler with the start of the line
  or side you are measuring and read the line where
  the side or object ends.

So this rectangle is 4 6/10 of a cm long or 4.6
cm long.
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Units for Length

• There are two major units for measurements
• Metric units are used all over the world.
• The base unit is the meter. All other units
  are meters multiplied or divided by a power of
  10.
• 1 centimeter (cm)10 millimeters (mm)
• 1 meter (m)100 cm1000 mm
• 1 kilometer1000 m100,000 cm1,000,000 mm

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Customary Units for Length

• U.S. customary units are only used in the U.S.
• The smallest unit is the inch, but on a ruler, an
  inch can be divided up into smaller
  pieceshalves, quarters, eighths, sixteenths,
  even thirty-seconds!
• 1 foot (ft.)12 inches (in.)
• 3 ft.1 yard (yd.)
• 1760 yds.1 mile (mi.)
• 5,280 ft.1 mi.

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Moving Between Units

• Sometimes you start out with one kind of unit,
  but you need another unit. For example, you
  might have 6 feet but want to know how many yards
  you have. Take one of the equations from
  beforein this case,
• 3 ft.1 yd.
• Since you are starting with feet, you divide the
  number of feet by 3 to find out how many yards
  there are. If you had started out with the
  number of yards, you would have multiplied that
  number by 3 to get the number of feet.

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Moving Between Units

• In general, if you are moving from the unit with
  the larger number (the smaller unit) to the unit
  with the smaller number in the equation (the
  larger unit), you will divide by the larger
  number to get to the next unit. If you are
  moving from larger unit to the smaller unit, you
  will multiply by the larger number to get the new
  unit.

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Moving Between Metric and Customary Units

• You can also change units from metric units to
  customary units and from customary units to
  metric units using the same methods and these
  equations.
• 1 in.2.54 cm
• 1 ft.0.305 m
• 1 yd.0.914 m
• 1 mi.1.61 km

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Measuring Perimeter

• Perimeter is the distance around the sides of an
  object or space.
• To find the perimeter of a shape, add the
  lengths of each of the shapes sides together.
  This sum is the perimeter of the shape.
• Because you are adding up units of length, the
  unit of a perimeter will be the same as the units
  used to measure the length.

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Measuring Area

• Area tells us how many squares you can lay out on
  a flat surface like a shape.
• To find the area of a
• Rectangle multiply the length of the object by
  its width
• Triangle Multiply the length of the triangles
  base by its height
• Different Shape Cut the shape into rectangles
  and triangles. Add the areas of these shapes to
  get the total area of the shape.
• Units You are measuring area in squares, so
  your units must also be squaressquare inches
  (sq. in.), square meters (m2), etc. Basically
  take the units that the length was measured in
  and let us know that they are now squares.

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Capacity Volume

• Capacity is how much you can fill a space with.
  We usually talk about capacity with empty
  containers.
• Volume is how much space an object takes up. We
  talk about volume with both solid objects (no
  empty spaces) and with empty containers.

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Measuring Capacity and Volume

• One way to measure the capacity or volume of an
  object is by using the lengths of the height and
  the sides of the base to find the volume of the
  solid. You will learn about this in later
  grades.
• Another way to measure volume is to find out how
  many cubes of the same size you can fit into the
  object.
• The other way you can measure the capacity or
  volume of an object is to find out how much
  liquid you can fill it with.

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Units for Measuring Volume with Cubes

• Your units in volume with always be cubic units.
  If you know the length of the sides of your cube,
  you use that unit and show that it is a cube.
• For example, if each side of your cube is 1 cm
  long, your unit will be cubic centimeters (cm3).
• If each side of your cube is 1 in. long, your
  unit will be cubic inches (cu. in.).

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Measuring Liquids

• We use measuring cups to measure liquids. When
  using a measuring cup, make sure you hold the
  level of the water in your line of sight or
  crouch down until the water line is in your line
  of sight and read the line that that water goes
  up to.

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Customary Units for Measuring Liquids

• 1 cup (c.)8 fluid ounces (fl. oz.)
• 2 c.1 pint (pt.)
• 2 pts.1 quart (qt.)
• 4 qts.1 gallon (gal.)

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Metric Units for Measuring Liquids
Like with metric units for length, all units are
the base unit (in this case the liter) multiplied
or divided by a power of 10. The main units you
will use in measuring liquids will be milliliters
and liters. 1,000 milliliter (mL) 1 liter
(L) A little connection with volume of
solids 1mL1 cubic centimeter (cc)
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Moving Between Customary and Metric Units for
Measuring Liquids

• 1 fl. oz.29.57 mL
• 1 gal.3.785 L
• 1 mL0.034 fl. oz.
• 1 L0.264 gal.

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Measuring Weight

• When most people talk about weight, they are
  really talking about massor how much matter or
  stuff is in something. Measuring an objects
  weight tells us how much matter is in it.
• We measure weight on scales and balances.

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Using Scales and Balances

• When using a scale like this one, make sure the
  scale is always set to 0 before you weigh
  anything. Once you put the object on the scale,
  the scale will show you how much it weighs.

There are two kinds of balances. With this kind
of balance, you put the object in one dish and
put weights in the other dish. When the two
dishes are balanced, you add the weights in the
other dish to find the weight of the first object.
With this kind of scale, you put the object onto
the dish and move the sliders along the three
rulers. When the line at the end of the arm
lines up with the line on the right side of the
balance dish, you add up the values on the rulers
to find the weight of the object.
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Customary Units for Weight

• The smallest unit is the ounce, although it can
  also be broken into smaller pieces or fractions
  of an ounce.
• 16 ounces (oz.)1 pound (lb.)
• 2000 lbs1 ton (T.)

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Metric Units for Weight

• The base unit is the gram, and all other units of
  weight in the metric system are grams multiplied
  or divided by powers of 10.
• 1000 milligrams (mg) 1 gram (g)
• 1000 g1 kilogram (kg)

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Moving Between Customary and Metric Units for
Weight

• 1 oz28.35 g
• 1 lb0.454 kg
• 1 g0.035 oz.
• 1 kg2.202 lbs.