measuring length (teach)

MeasuringLength and Distance

By Moira Whitehouse PhD

It is said that long, long ago, people used the length of the king’s foot to settle arguments about how long or wide something was.

So that everyone would know how long his foot was, the king passed out sticks the same length as his foot. The sticks were called the ruler’s foot or “rulers.”

•Then, about 200 years ago, someone decided that measurement systems would be better based on Mother Earth than on some king’s foot.

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•And divided that distance by:

•So, using mathematics, they figured the distance from the equator to the north pole.

10 Million

The MeterAnd the answer to that division problem was named:

•A whole system of measurement was developed with the meter as its basis.

The system is called the System International or the Metric System.

•The Metric System is based on dividing the meter by the number 10 or multiplying it by some multiple of 10.

•Considering the various numbers we used in the English system (12 inches to a foot, 3 feet to a yard, 1760 yards to a mile , etc. etc.) multiplying or dividing by 10 makes the Metric System seem easy.

Some of the tools used to measure length and distance are a metric ruler, a meter stick and a metric tape measure.

• By convention, the units decimeter (10-1), decameter (101) and hectometer (102 ) are seldom used.

•Meters or kilometers are used to measure longer distances or longer things such as school buses.

•The units usually used to measure length and distance are the millimeter (10-3), the centimeter (10-2), the meter, and the kilometer (10 3).

http://www.flickr.com Wagner T. Cassimiro "Aranha"'

•Smaller divisions of the meter (millimeters and centimeters) are used to measure the length of shorter distances or things (like pieces of chalk or height of a school desk).

•For measuring longer distances, meter sticks can be placed one after another along the distance, counting the total number.

•Here we have drawing of a decimeter; it takes 10 of these to make up a meter.

•Here is a drawing of one of the 10 centimeters found in a decimeter.

•An accurate drawing of one ofthe 10 millimeters found in a centimeter would be onlyas long as a dime is thick.

This drawing shows 1/10th of a meter stick, a decimeter (dm). It has 10 centimeters (cm) and each of those centimeters has 10 millimeters (mm) that are just about the thickness of a dime.

The arrows indicate specific mm locations.

Before getting some practice in measuring length, it is important to understand that scientists use the meter as the basis for measuring mass and volume as well as length.

• Length/Distance: how far from here to there in

•Kilometers (thousands of meters....Fort Worth to Dallas, 50 Km)

•Meters (a school bus, about 10 meters)•Centimeters (top of your desk, about 70

Cm) •Millimeters (width of a dime, 1 mm)

Volume: Scientist also use the meter (cubic meters) to measure volume (how much space something takes up.)

•That is because the amount of water that fits into 1 centimeter cubed has a mass of 1 gram and the gram is the unit we use to measure mass.

Mass: And in a round about way, scientists even use the meter to measure mass.

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”.

Stated as centimeters

We will start by measuring distance, first by finding the correct millimeter and stating the answer in centimeters for “A” through “G”. First, “A”.

Stated as centimeters

18 mm 1.8 cm

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. First, “A”.

Stated as centimeters

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “B”.

18 mm 1.8 cmStated as centimeters

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “B”.

18 mm 1.8 cm32 mm 3.2 cm

Stated as centimeters

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “C”.

18 mm 1.8 cm32 mm 3.2 cm

Stated as centimeters

18 mm 1.8 cm32 mm 3.2 cm44 mm 4.4 cm

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “C”.

Stated as centimeters

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “D”.

18 mm 1.8 cm32 mm 3.2 cm44 mm 4.4 cm

Stated as centimeters

18 mm 1.8 cm32 mm 3.2 cm44 mm 4.4 cm

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “D”.

59 mm 5.9 cm

Stated as centimeters

18 mm 1.8 cm32 mm 3.2 cm44 mm 4.4 cm59 mm 5.9 cm

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “E”.

Stated as centimeters

18 mm 1.8 cm32 mm 3.2 cm44 mm 4.4 cm59 mm 5.9 cm

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “E”.

75 mm 7.5 cm

Stated as centimeters

18 mm 1.8 cm32 mm 3.2 cm44 mm59 mm 5.9 cm75 mm 7.5 cm

4.4 cm

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “F”.

Stated as centimeters

18 mm 1.8 cm32 mm 3.2 cm44 mm59 mm 5.9 cm75 mm 7.5 cm

4.4 cm

87 mm 8.7 cm

We will start by measuring distance, first by finding the correct millimeter and then then stating the answer in centimeters for “A” through “G”. Then, “F”.

Stated as centimeters

18 mm 1.8 cm32 mm 3.2 cm44 mm59 mm 5.9 cm75 mm 7.5 cm

4.4 cm

87 mm 8.7 cm

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “G”.

Stated as centimeters

18 mm 1.8 cm32 mm 3.2 cm44 mm59 mm 5.9 cm75 mm 7.5 cm

4.4 cm

87 mm 8.7 cm

We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “G”.

96 mm 9.6 cm

Stated as centimeters

How long is Mr. Toad?

How long is this fish in millimeters?

How many centimeters is that?

The butterflies wing span is _________mm or stated in centimeters is ____________.

The caterpillar’s length in millimeters is _________ or stated in centimeters is ____________.

Some rulers start at the very end of the stick and others have a small space before the actual ruler starts.

Placement of one of these screwdrivers will get you the wrong answer for the screwdriver’s length.

• Is this screwdriver 900 millimeters long (that is the same as 9 centimeters)?

•Or is it 940 millimeters long (that is the same as 9 centimeters plus 4 millimeters?

What is the length of this tooth pick?

In millimeters? Stated in centimeters?

What is the length of this paper clip in millimeters? Stated in centimeters?

•Here is a little “pop” quiz as we finish discussing the measurement of length.

• millimeters

•How tall are you are in these metric length units?

• centimeters

• meters

•In pairs, measure your height with a meter stick or metric measuring tape.