Christopher and Kate make sense of an applet called Races by first entering different values of distance and time for two cars and then noticing what happens.
For use in a classroom, pause the video and ask these questions:
1. [Pause video at 1:04] What might Christopher be thinking when he says the blue car is already going faster?
2. [Pause video at 2:14] How do you think Kate knows that the red car is going slower than the blue car? [After students share their ideas, continue watching the video until 2:25. Then ask, “What is Kate’s thinking?
Have students run several races with the applet by entering different amounts of time and distance for each car. You can support student’s emerging skills in engaging in mathematical dialogue as follows:
1. Ask students to work with a neighbor to write down everything they notice about the applet. Have a student share one thing that they noticed about the applet with the entire class.
2. Ask the students if they noticed the same thing.
3. Then ask the students for something else that they noticed.
4. Repeat the question cycle. Continue to ask students what they noticed until many observations have been shared.