Transcript What is a Scientist? - Cockeysville Middle School

Objective: To use unit fractions to covert
quantities from one form to
another.
Core Question: How can you convert metric quantities
using unit fractions??
Drill: With your neighbor, come up with a
strategy to solve the problem below.
22 tons = ___ dag
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When converting between metric units, you can
always move the decimal point to get the
correct value. However, there are times when
you have to convert from one system to another
(metric to customary) or within an
other system (i.e. time). In these cases a
different system is needed because the units are
not based on the number 10.
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The method to be used is the Unit Conversion
Method. This is based on the fact that any time
you multiply a quantity by “1”, the value
remains the same even if the form of the
quantity changes. In this method you multiply
the initial quantity by a specially chosen
fraction (equal to 1 whole) that results in a new
quantity with the desired units.
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Example
2.5 feet = ____ inches
2.5 feet ×
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12 inches/1 foot
= 30 inches
(special form of “1”)
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Let’s complete the drill.
22 tons ×
How can we convert tons?
1 ton = 2000 pounds
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Let’s continue.
22 tons ×
2000 pound
1 ton
= 44,000 pounds
How can we convert pounds?
1 pound ≈ 0.453 kg
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Let’s continue.
44,000 pounds ×
0.453 kg
1 pound
= 19,932 kg
22 tons = 19,932 kg
How can we convert kg?
1kg = 100 dag
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Let’s continue.
19,932 kg ×
100 dag
1 kg
= 1,993,200 dag
22 tons = 1,993,200 dag
1.9932 x 106 dag
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How about a couple more problems?
9.5 hours = _____ seconds
327.6 hg = _______dg
27.8 L = ______ cm3
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Homework:
1. Unit Conversion Ditto
(selected problems)
2. Study for Quiz.
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