Slope Lesson Plan (grade 9)

Teacher: Mr. R. Austin

Class: Grade 9 Math

Objective: Discussion of the slope of a line using the relationship slope=rise/run.

Background Information: Students have already been exposed to the coordinate system earlier in the course and also in grade 8. They should be able to draw a straight line by connecting two points.

Materials: Minds on Math, Lynda Colgan et al., Addison Wesley, Don Mills, Ont., 1995. (p143-145).

5-6 balls, textbooks, graph paper, meter sticks, protractors

Opening Set: Todays lesson is going to deal with a mathematical topic that is associated with why you can roll faster down steeper hills, ski faster down steeper hills, or if you are a wimp, go slower down the bunny hill.

Activity/Body of Lesson: This lesson will involve students working together in groups of four at the beginning of the lesson and then a more indepth discussion about slope.

• Have the students in groups of four create an incline using a couple of textbooks.
  
• Get them to roll an object down the incline and ask the students if they can describe the mathematics related to this exercise.
  
• Ask them to make their incline steeper and perform the same exercise as before asking the same question.
  
• Have the students use a meter stick and a protractor so they can associate greater angles with greater slope (angle between the horizontal and the meter stick).
  
• Through the use of a coordinate plane drawn on the chalk board, illustrate what was done with the textbook demonstration.
  
• Steeper the book, the faster the ball rolled. Angle from the horizontal greater in the second incline than in the first.
  
• Introduce the idea of rise and run using these diagrams (ensure that each student understands what is meant by this).
  
• At this point get the students to divide the rise by the run (i.e. rise/run). Have the students compare the rise/run for the first and second illustrations. Inform the students that what they have been calculating is referred to as the slope of the books.
  
• Do two examples on the board making sure the students get involved and understand what is being done. (i) A(1,2) B(2,4) slope=2, (ii) A(2,4) B(3,2) slope=-2. Be sure they are not confused by the idea of negative slope. Tell them to keep in mind: upward or to the left-positive slope, downward or to the right-negative slope.
  
• Tell the students about the two special cases:
  

  (i) Horizontal line (slope=0)
  

  (ii) Vertical line (slope=undefined)
  

  -explain this is because you cannot divide by zero.
  

Do a quick review of everything covered in class. Ask if there are any other questions concerning slope.

Seatwork: Exercises dealing with slope (Minds on Math, p143 #1&2).

Evaluation:

• Did the students understand the concept of slope with regards to rise/run.
  
• Was my lesson interesting enough that the students were attentive all of the time?
  
• There should be at least one question on the unit test dealing with slope.

Closure:

• Tell the students that in the next class we will be applying the idea of slope to some real life examples similar to the seatwork.
  
• Remind them about the upcoming unit test.