MS1 Science1:

Unit Conversion

Quick Review: SI Units

Prefixes

Imperial Units

Physical Quantity SI Unit Imperial Unit
length meters feet
mass kilograms pounds
time s s

Imperial Units Don't Have Prefixes

SI Unit with Prefix Imperial Unit
kilometer mile
meter feet
centimeter inch

Imperial units use a different unit for everything!

Unit Conversion Practice

1 km 0.621371 miles

How many miles are in 10 km?

10km \times 0.621371 \dfrac{mile}{km} = 6.21371miles \approx 6\ miles

How many miles are in 50 km?

Unit Conversion Practice

How many kilometers are in 10 miles?

10miles \times 1.60934 \dfrac{km}{mile}= 16.0934 km = \\ \approx 16\ kilometers

How many kilometers are in 50 miles?

1 mile 1.60934 km

Looking Up Conversion Factors

Why Doesn't America Use Metric?

Example1: Air Canada Flight 143

A flight on Canadian Airlines ran out of fuel due to a calculation error. The weight of the plan's fuel was measured in pounds instead of kilograms.

1 pound 0.453592 kg

This means the plane had less than half the fuel it was supposed to have. Luckily the pilots were able to make an emergency landing.

Example: Space Probe

In 1998 NASA managed to crash a 200 million dollar space probe into the surface of mars, because of a mistake converting from imperial to metric units.

The probe was completely destroyed 

Homework Problems

1. In the U.S. milk is sold by the gallon. How many liters of milk are in two gallons?    *1 gallon = 3.8 liters.

 

2. Take your weight in kg and convert it into pounds.

1 kg = 2.2 pounds

 

3. Take your height in centimeters and convert it into inches. (look up the conversion factor online.)

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