BACKGROUND:
Measurement has been
used by ancient civilization for thousands of years. The first standard
system of weights has been traced to the Egyptians and Babylonians.
The Egyptians in about 3500 BC used scales to measure food. The imperial
or English system that the United States uses today, developed in the 1300's
with King Edward I in England. The metric, based on a system of 10,
was developed and used in the 1790's.
There are two systems commonly
used to measure things. The English system is used almost exclusively
in the United States. The metric system is used throughout the world
in people’s everyday lives. Scientists use the metric system throughout
the world. This helps to standardize observation and data collecting.
The metric system is the preferred system of measurement because it is
easier to work with. Sometimes you are asked to convert from one
system to another. In this lab students will be converting from the
English system to the metric system.
PROCEDURE:
- Use a portion
of this lab to go over science procedures specific to your classroom.
If in a science lab, discuss safety, care of materials, and other lab procedures
that are specific to the students' lab area. If in a classroom situation,
give rules on how tables will be arranged, safety, and other procedures
that are needed to make science "successful and enjoyable for all!"
With any new group of students, discuss lab partners and working in cooperative
groups. Emphasize that it is helpful to work with people to gain
their insight and knowledge when experimenting. In science research,
it is very common for "working groups" to develop.
- The second part of this
lab is to help students become familiar with the measuring tools of science,
with an emphasis on volume. Since these measurements involve liquids,
make sure to consider spills. Suggestions to reduce spills in experiments
include meat trays (from the grocery), a tub, or a sink. Students
sometimes have trouble getting the "exact" level. Practice will solve
this problem. Some students may realize they could have used math
to figure out how many milliliters make up the given quantity.
- Go over the difference
between the metric and the English system. Metric uses base ten.
English uses a unit of measurement that has a historical rather than mathematical
basis. Metric measurement is the easiest to learn and remember.
- In exercise 1, the students
will measure a volume of water in English. They will then try to
find out how much this equals in the metric system.
- In exercise 2, use any
containers as unknowns. Students may bring in 2 containers from home.
The students should first predict and then measure the volume of their
containers.
- When the students have
finished, go over the answers and discuss how many milliters are in each
container. Explain that by measuring in one system and then finding
the same volume in another system we can determine a conversion.
Inform students that conversions are "mathematical." They will learn the
2 systems by measuring with both systems to get a "feel" for the amounts.
- ANSWERS:
250 ml = 1 cup; 500 ml = 2 cups;
62.5 ml = 1/4 cup; 125 ml = ½ cup;
15 ml = 1 tablespoon; 625 ml
= 2 ½ cups; 312.5 ml = 1 1/4 cups
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