Everyday mathematics Grade 4 Lesson 4.8 Metric Units of Length Objectives: to review the relationships among metric units of length and to guide students as they work with metric units.

Math message  Find at least three examples of measurements in your student reference book – write then in your ISN

Customary and Metric  What is the difference between US Customary Units and Metric Units?  Can you name three examples of each?  Why do we learn about metric units when we live in the United States?  Have you ever seen metric units here in the U.S?

Reasons to learn the metric system  Manufacturers increasingly use metric system (especially in measuring). Car parts are mostly measured in metric units.  Scientists EXCLUSIVELY use the metric system.  Most other countries use the metric system.  Many sports statistics are measured in metric units – for example the Olympics measure distance, weight, and speed in metric units.

Rulers  Get a ruler. Can you find both US customary units (inches) on one side?  Can you find metric units (centimeters) on the other side?  Looking at the metric side of the ruler… What do the bigger numbers stand for?  What do the small marks in-between stand for?

Metersticks  Get a meterstick.  How many centimeters are in a meter?  How many millimeters are in a centimeter  How many millimeters are in a meter?  How many centimeters are in a decimeter?  How many decimeters are in a meter?

Conclusions  Each metric unit is ten times greater than the next-smaller standard unit.  A centimeter is 10 times longer than a millimiter.  A decimeter is 10 times longer than a centimeter.  A meter is 10 times longer than a decimeter.  a meter is 100 times longer than a centimeter and 1000 times longer than a millimeter!

symbols  The symbols (abbreviations) used for the metric system are as follows: mm millimeter(s) mm millimeter(s) cm centimeter(s) dm decimeter(s) m meter(s)

conversions  How many decimeters are in 5 meters?  How many centimeters are in 3 meters  How many centimeters are in 8 decimeters?

Practice measuring (with a partner)  Measure the following objects (to the nearest centimeter) and record the answers on your workbook page 96.  1- the height of your table  The length of the table  The distance from one end of the room to the other.  The distance around a partners wrist (feel free to use the tape measure)  The height of a door.

Convert to meters  Take the measurements on page 96 (the ones you just completed) and convert each centimeter measurement to it’s meter equivalent.  For example if you found that the height of a picture frame was 37 centimeters, it would equate to.37 meters.

Math boxes  Complete math boxes 4.8 on page 97.  IN your ISN’s explain how you knew which number was closer to 47 (problem 6a).

Homework  Page 128 Measuring in Centimeters is the homework for this lesson.  Record the line segments in both centimeters and meters.

Metric Prefixes  Page 130 – Metric Prefixes  (keep this page in your ISN when it is complete!)  Research with your nooks, or at home… (answers after this slide)

Metric prefixes  Terameter tera- 1,000,000,000,000  Gigameter giga- 1,000,000,000  Megameter mega- 1,000,000  Kilometer kilo- 1,000  Hectometer hecto- 100  Decameter deca- 10  Meter 1

Metric prefixes  Meter 1  Decimeter deci- 1/10  Centimeter centi- 1/100  Millimeter milli- 1/1,000  Micrometer micro- 1/1,000,000  Nanometer nano- 1/1,000,000,000  Picometet pico- 1/1,000,000,000,000