Meaning of Average Rate of Change, Clip 2, 1:40

• The teacher gets the students thinking about how accurate their calculation is by asking about the length of the time/distance interval they use, a question she asked of all the groups.
• The teacher also is beginning to introduce the language that will be used during the course, in this case that they are dealing with a change in time and a change in distance.
• The teacher makes move to ask if it is the actual speed to which the students respond it is an average speed, she then asks them to describe what that is, the students have  a tough time verbalizing it at first.
• Notice that the teacher helps them with their description as they are having a tough time verbalizing.
• Her questioning of the groups is helpful in getting them to think about the meaning of average speed and how that differs from instantaneous speed.