1. Pre-Lab 3B: Experiments and Variables

2. Purpose Experiments help us collect evidence so we can unlock nature’s puzzles. If an experiment is well-planned, the results can provide an answer to a scientific question like “What would happen if I did this?” If the experiment is not well-planned, you will still get results, but you may not know what they mean. so….. “Front load” the experimental set-up. In this investigation, you will experiment with a car on a ramp. Only by paying careful attention to the variables can you make sense of the results.

3. Key Question How do you design a valid experiment?

4. Background Define: variable experimental variable control variable

5. Drawing Draw this: (w/o text)

6. Procedure Imagine I am making lemonade. What would I need to make it: list the items? This exercise is called a system. What are all these items in the system called? What would happen if I added more ice? What would happen if I added more sugar? Why should you change only one of these variables at a time?

7. Section 1: Lab station 1 put your ramp on the lowest hole. Each lab station will have their ramp on the hole which is the same number as their lab station counting FROM THE BOTTOM. Therefore, each station will have a different angle. Place the clay ball on the stop at the bottom, why? Return to teacher when lab is completed.

8. Section 1 cont: Place the photogates where your team thinks ANYWHERE you want: -together -far apart -near the top -near the bottom Photogates are nose tightened to the ramp Roll your car and record in table 1 the time (Tab) between photogates

9. Section 2: You will write a formal hypothesis, use the: “If…Then… because” format, so… You need to relate the car’s travel with: -at different ramp angles -how the photogate TIME will change DO THIS RIGHT NOW!!! Record your data in the chart (column 2 only) but, you need a chart with 7 data rows, why? So, add 3 rows to the example shown in the lab book, Collect the 6 other lab station times and record Read question 2c: you have to answer both of these and based only on the first time trial of data table 1.

10. Stop the pre-lab and lab here until sections 1-3 have been completed Section 4: You now need to have STOPPED the lab!!!! We need, as a class, to discuss how you are going to control all the variables. Tell me again why? What are the variables effecting this lab? Now, how should we control/front load them? Now that you have better restricted the variables, do a second time trial and record in your data table

11. Post Lab 3B: expt/variable Experiments help us collect evidence so we can unlock nature’s puzzles. If an experiment is well-planned, the results can provide an answer to a scientific question like “What would happen if I did this?” If the experiment is not well-planned, you will still get results, but you may not know what they mean. In this investigation, you will experiment with a car on a ramp. Only by paying careful attention to the variables can you make sense of the results.

12. Key Question How do you design a valid experiment?

13. Background Define: variable experimental variable control variable

14. What should your hypothesis have been (format)? How did your initial results compare to your hypothesis? What are six variables effecting the lab? What was the experimental variable? What should be done with the variables and why? What two variables should not be included? Why did the second trial produce better agreement with your hypothesis?