Grade 3 introduction to standard units and sketch the line
SS3.3. Demonstrate an understanding of linear measurement (cm and m) including: selecting and justifying referents generalizing the relationship between cm and m estimating length and perimeter using referents measuring and recording length, width, height, and perimeter constructing 2-D shapes with a given perimeter or given lengths. Before: Open ended problem/ discussion. This has many ways to enter the problem. It is a safe way for all students to be a part of the discussion.Unit: paper clip or p.c. Ms.Lukey Mrs. MuirDesktop 12p.c. 19p.c. We both used paperclips. Why do you think our measurements are not the same? ------------------------------------------ Show students a paper clip. Talk with students about how they measured using this paper clip. How did they record their unit? EX.5 p.c.pc meaning paper clip We labeled the unit with a symbol so that everyone would know we used the unit paper clip. Now hand out a smaller paper clip. What would happen if Miss.Lukey and I were asked to measure the desk using paper clips? We would both use paper clips because we know that we need to use the same unit in order to get the same measurement. If I used this small paper clip and Miss.Lukeyused the large paper clip tell me about our measurements? Grade 3: (This is where the concept of Standard Measurement comes into the lesson. What do you think standard is? Why is it important to have standard units?) A centimetre is a standard unit used to measure length. It is about the length of the width of your small fingernail. Pass out base ten blocks ones and tens. Have the students examine these math materials and ask what they notice about them? A “one” is a cm cube. It has a length, width and height of one centimetre. What about the “rod” or ten stick? What would the dimensions be of it? How could we use a ten rod to measure length?
Have students take out their ruler.Demonstrate using the SMART board how to measure lining up with the zero mark on their ruler.Pass out a worksheet for students to practice measuring using the unit centimetre.Talk in large group their measurements.DuringIntroduce a game called “Sketch the Line”Materials needed:Paper, cm ruler, two dice for each pair of students,pencilRules: 1. Students will be with a partner. 2. Roll the dice. Add the numbers. 3. Both players try to sketch a line that is this many cm long. 4. Draw a line that is the correct length below each sketch. Use a ruler. 5. The player whose sketch is closer to the correct measurement wins 1 point.AfterTalk to the students about the game. What did they find easy? Difficult? Why?