Activity
Ask the students, “If a pen pal of yours, who lives
in Germany, writes that she is 182 cm tall, would you know
if she’s taller or shorter than you are? How would
you tell her your height if all she knows is the metric system?”
Tell the students, “Most of you have grown up using
the US/Imperial units for measuring distance, weight, and
volume. But most other countries use the metric system. Science
teachers require that you know and use the metric system.
Why do you think this happens?” Allow time for discussion
of how the systems are different and why the metric system
is more uniform.
Put up the US System of Measures Overhead, found at the
following web site http://www.ex.ac.uk/cimt/dictunit/dictunit.htm#US to show the students just how complicated our system is with
the varied numbers you need to remember to change from one
unit to another.
Put up
the Metric System of Measures Overhead found at the following
web site http://www.ex.ac.uk/cimt/dictunit/dictunit.htm#metric to show how the metric system is based on always using
10 to change from one unit to another.
Remind the students that they have probably seen many of
the prefixes on the metric units of measurement before. Put
up the Metric Prefixes overhead found at
http://www.convert-me.com/en/metric_conversions_en.html Tell
the students that between “deca” and “deci” is
where the regular unit (meter, gram, etc.) would go. Tell
the students that they should definitely know the prefixes
from “milli” to “kilo” and how to
convert from one unit to another. Two good web sites for
checking the students’ abilities to convert between
the units of the metric system are http://www.coe.uh.edu/archive/science/science_lessons/scienceles3/metric/metric.html#metricch and
Metrics PowerPoint
presentation by Dr. Register - Rogers State University,
Oklahoma. (http://www.drregister.com/resources/sciprof/ppts/)
Ask the
students, “How do we convert from US units
to metric units or the other way around? What do we need
to know and what do we need to do?” Go to either of
the following web sites http://www.bartleby.com/61/charts/M0182500.html or
http://hemsidor.torget.se/users/b/bohjohan/convert/conv_e.htm to
find the following conversion factors.
1 km  0.62
miles |
|
(
1 mile 1.61
km ) |
| 1
cm 0.39
inches |
|
(
1 inch 2.54
cm) |
| 1
kg 2.20
lbs |
|
(
1 lb .45
kg) |
| 1
US gallon 3.78
liters |
|
(
1 liter 0.26
US gallons) |
| 1
quart 0.95
liters |
|
(
1 liter 1.05
quarts) |
Have the students estimate the following conversions without
calculators.
1. 20 miles _____
km
2. 25 kg _____
lbs
3. 100
cm _____
inches
4. 15
gal _____
liters
Have the students find the exact values by using a method
called unit analysis. Do the following problems with the
students, making sure that the students state and cancel
the units as they do the problems.
Homework The one
of the common problems associated with traveling outside
of the USA is being able to estimate how the measurements
compare to what we use. This site is an excellent one to
help you understand those road signs and store quantities
when traveling in Europe or anywhere else that uses metric.
1. A road sign shows 150 km to Paris. How far would that
be on your car's odometer?
2. The speed limit is 120 km per hour. How fast should you
be going?
3. Your hostel is at an altitude of 1100 meters. How many
feet above sea level is it?
4. You can take 25 kg on the airplane as carry on. How many
pounds can you take?
5. Would 50 g of bologna be enough for two sandwiches?
6. Your car takes 40 liters to fill the tank. How many gallons
is this?
http://www.uen.org/utahlink/activities/view_activity.cgi?activity_id=10184
7. A friend asks how many km it is from Los Angeles to San
Francisco, a distance of 385 miles.
8. You have a 3000-gallon swimming pool. How many liters
would it take to fill the pool?
9. My cat is 35 lbs. How many kg is this?
10. Convert your height from feet and inches to centimeters.
|
