3. distance
variable
evidence
error
controlled variable
rate
speed
tested variable
time interval

4. What things can contribute to a car accident?
Record your answer in your notebook.

5. How do you think speed is measured?
Share your ideas with the class.

6. How did people measure speed before technological devices were invented?
Share your ideas with the class.

7. Read the introduction and look for key ideas
This car speedometer shows speed in miles per hour and in kilometers per hour. Kilometers per hour is the speed unit commonly used in other countries.

8. How can you measure the speed of a moving cart?

9. Review the procedure
Why do you think you are asked to do three trials?

10. Potential errors

11. Complete procedure part A
speed = distance/time What is the speed of a car that travels 100 miles in 2 hours? What is the speed of a car that travels 30 kilometers in ½ hour?

12. Class results for cart speed

13. Complete procedure part B
SCORING GUIDE: Designing Investigations

14. Experimental design

15. Analysis question 1
According to your data from Part A, what is the speed of the cart?

16. Analysis question 2
According to your data from Part B, what is the effect of release height on speed?

17. Analysis question 3
List some common units for speed. Why are there so many different units?

18. What unit would be most convenient to measure how fast your fingernails grow?
Share your thoughts with the class.

19. Analysis question 4
What part(s) of your experimental design in Part B:
increased your confidence in the results?
decreased your confidence in the results?

20. Analysis question 5 What is a car’s speed in m/s if it travels:
5 meters in 0.1 seconds?
5 meters in 0.2 seconds?
10 meters in 0.2 seconds?

21. Analysis question 6
Reflection: Why do you think speeding is a factor in about 20% of fatal car accidents?

22. What is a rate?
Brainstorm examples of rates and describe two measurements needed to determine the rate. Share your answers with the class.

23. How can you measure the speed of a moving cart?

24. Key vocabulary definitions
Distance - The length measured between two points. Evidence - Factual information or data that supports or refutes a claim.

25. Key vocabulary definitions
Error - Unavoidable variation between a measurement and the true value of a quantity that occurs when measurements cannot be made with greater accuracy. Controlled variable - A variable in an investigation or experiment that is held constant.

26. Key vocabulary definitions
Rate - A ratio of two different kinds of measurements. Speed, the ratio of distance to time, is an example. Speed - The rate at which an object moves, equal to the distance traveled per time interval.

27. Key vocabulary definitions
Tested variable - A variable that is changed in a systematic way in an experiment or investigation in order to determine its effect. Time interval - The time between two events. Variable - A factor in a scientific experiment that can vary.

28. Compare results
Post your results on the Issues and Physical Science page of the SEPUP website, and compare your data set to that of students in other classes.

29. Calculate
If the speed limit is 60 MPH, could the police give a speeding ticket to any of the drivers of the cars in Analysis Question 5? Hint: 1,000 m = 1 km = 0.62 miles