1. What aspects of an object are measureable?

2. Learning Target:Students will learn how to measure length accurately using customary and metric units and estimating them using benchmarks.

3. Customary Units:inches (in.)foot (ft)yard (yd)mile (mi.)How they are related to one another:1ft = 12in. 1yd = 3ft = 36in.1mi. = 1,760yd = 5,280ft

4. Metric Units:millimeter (mm)centimeter (cm)meter (m)kilometer (km)How they are related to one another:1cm = 10mm 1m = 100cm = 1,000mm1km = 1,000m

5. Common measuring tools:foot rulercentimeter ruleryardstickmetersticktape measureHow many units on are each?

6. How many units on are each? foot ruler -12 inchescentimeter ruler – 30 centimetersyardstick – 3 footmeterstick – 100 centimeterstape measure – can vary but normally has both customary and metric units

7. Choose an appropriate measuring tool for the length. Explain your reasoning.1. Diameter of a circular pool.2. Diameter of a car tire.Common measuring tools:foot ruler centimeter ruleryardstick metersticktape measure

8. Answers: 1. Diameter of a circular pool.A tape measure; the pool’s diameter is greater than one yard an greater than one meter.2. Diameter of a car tire.Yardstick or meterstick; the tire’s diameter is greater than one foot and greater than 30 centimeters and less than one yard and less than one meter.

9. Measure the length of the spoon to the nearest inch.http://www.future-edge.com/blackboard/MathM3B211/images/spoon.jpg

10. Answer:4 in.http://www.future-edge.com/blackboard/MathM3B211/images/spoon.jpg

11. Find the length of the object to the nearest centimeter and millimeter.Nearest centimeter = 3 cmNearest millimeter = 34 mmhttp://physicspmb.ukzn.ac.za/OnlineExercises/IntroVernier/Figures/Fig3.gif

12. Find the length of the line segment to the nearest centimeter and millimeter.http://www.future-edge.com/blackboard/MathM3B211/images/screw.jpg

13. Answer:5 cm51 mm http://www.future-edge.com/blackboard/MathM3B211/images/screw.jpg

14. What benchmarks can we use to estimate the measure of an object?

15. Benchmarks for Units of LengthCustomary Units:inch – length of a small paper clipfoot – distance from elbow to knuckleyard – width of a doorMetric Units:millimeter – thickness of a dimecentimeter – width of your little fingermeter – height of a chair

16. Choose an appropriate customary and metric unit for length. Explain your reasoning.1. width of our classroom2. distance across town

17. Answer: 1. width of our classroom -feet, yards, or meters; the width is much greater than 1 in. or 1 cm and much less than 1 mi. or 1 km2. distance across town –miles or kilometers; the width is much greater than 1 yd or 1 m.

18. Can you measure length accurately using customary and metric units and estimating them using benchmarks?