Key Questions 2.1 : Modeling car s speed

2. Key Questions2.1 : Modeling car’s speed How do we measure and describe the world around us? What is speed and how do we measure it? Can you predict the speed of the car at any given point on the ramp?

3. Review Set up and explain how you would use the photogates and timer to find the average speed of the car on the ramp Set up and explain how you would use one photogate on the ramp to find an instantaneous speed of the car at some point on the ramp

4. Review What does the timer display for you when the A light is on? B light? Both A and B lights? No lights? Does the timer reset itself? Do you have to run the car down the ramp multiple times to get the time at A, time at B, and the time from A to B?

5. Investigation 2.1What Are Models? Scientific Model Physical Model Conceptual Model Graphical or Mathmatical Model Define these vocabulary words for the students and have them give examples. Examples can be found in the textbook on pp.24-26. Point out that models are a good way to examine a complex question as smaller questions. Models also demonstrate how variables relate to one another. Define these vocabulary words for the students and have them give examples. Examples can be found in the textbook on pp.24-26. Point out that models are a good way to examine a complex question as smaller questions. Models also demonstrate how variables relate to one another.

6. Developing Models Does the car travel the same speed the entire way down the ramp? How much faster is it going at the bottom? Twice or three times as fast? Can we develop an experiment to answer this question? After answering these questions have the students describe how they would go about developing a model to answer these questions or to test their predictions. The students should realize that a physical model can be used as an experiment to test variables. After answering these questions have the students describe how they would go about developing a model to answer these questions or to test their predictions. The students should realize that a physical model can be used as an experiment to test variables.

7. What materials will we need? What are the variables? Which is the independent, and which is the dependent? What do we do with the variables we are not testing? Developing An Experiment After answering these questions have the students describe how they would go about developing a model to answer these questions or to test their predictions. The students should realize that a physical model can be used as an experiment to test variables. After answering these questions have the students describe how they would go about developing a model to answer these questions or to test their predictions. The students should realize that a physical model can be used as an experiment to test variables.

8. Developing An Experiment What data will we record? Time through the photogate Position of photogate What will we need to calculate? Speed of car, d/t (tricky! What is the value for d?)