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Year 7 Spring 1 Lesson 2: Measuring anglesObjectiveTo measure angles accurately using a protractor.AimMeasuring angles is often overlooked as a separate teaching point as it is assumed that students are competent in this skill. However, this is regularly not the case.This lesson emphasises angle as a measure of turn before using a full 360° to measure angles. The diagrams used at the start of the Powerpoint intentionally place the starting line as the positive x-axis to relate to future work on the unit circle.Students are encouraged to estimate the size of angles before measuring.When measuring angles this starting line moves so that students can think about where to place the zero line.Resources HYPERLINK "" PowerpointClass set 360 protractors (Powerpoint will have to be altered if you are using half protractors)Worksheet1 copy of Interlocking circles sheet enlarged to A3:Cut the circles from the sheet, cut the slits then slide the two together to make a manipulative to show the classMake different angles by turning one circle, keeping the line AB horizontal at this point, and measuring anti-clockwise:Key words: Angle, turn, acute, obtuse, reflex, right angle, half turn, full turn, anti-clockwise, protractor.Settler: Numeracy Ninjas (max 10 mins)Activity 1: Use the interlocking circles to ask students what happens as the line AC rotates anti-clockwise. As students to estimate the sizes of the angles and how they came to that estimation.The link to the NRich Estimation game is in the Powerpoint. (Look at the instructions and a possible approach for use here )Questions for progressionHow did you decide on your estimation?Which angles are useful markers?What are the names of the angles that are smaller than 90 degrees?Which word describes angles between 1 and 2 turns?What do we call angles that are bigger than 180 degrees?Activity 2: Show the slides on how to measure shapes using the full circle protractor.Emphasise putting the zero line on the line AB, and measuring anticlockwise. Do the first question together using the visualiser if available.Students then work through the first two sections of the worksheet. In the first section all have the line AB as horizontal, but different sizes of angle.The second section has the angles turned, but keeps the labels on as students often struggle to measure angles that look like that.The third section removes the labels. However all the angles in the three sections are the same size.Little progressStruggle to measure the angles in section 2Questions for progressionOn which line do you put the zero line?Where is line AB?Where do you put the centre of the protractor?If you turn the paper around does it make it easier?Some progressStudents struggle how to place the protractor in section 3.Questions for progressionCan you label the diagram?Which line would be AB? Why?Is there more than one way to measure the angle?Substantial progressAnswer sections 1 – 3 well.Questions for progressionAsk students to answer the final two questions.How accurate was your measuring?How do you know?-62865129540Acknowledgement:NRich Estimation gameNRich Star Polygons0Acknowledgement:NRich Estimation gameNRich Star Polygons ................
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