Bellringer

1. Bellringer • What should you do if your data in your experiment is inaccurate or your experiment is flawed? • What step do you complete after you gather information? • What do we call a possible explanation, answer to a question or an educated guess? • What is data?

2. Identifying Variables&Designing Investigations

3. 3 Kinds of Variables • Independent Variable – something that is changed by the scientist the ‘I control’ variable • What is tested • What is manipulated

4. 3 Kinds of Variables • Dependent Variable – something that is affected by the change in the independent variable • What is observed • What is measured • The data collected during the investigation

5. 3 Kinds of Variables • Controlled Variable – a variable that is not changed • Also called constants • Allow for a “fair test”

6. In our math problems we used independent and dependent variables too! Independent variable (The one number we changed) 2+2=4 Dependent variable Constant (The number that depended on the independent variable) (It stayed the same)

7. A birdy example… Imagine you want to see what color of bird feeders your local birds preferred. Red? Blue? Green?

8. Our Experimental Design

9. If everything except the independent variable is held constant, we can say: The experiment is FAIR. (ONLY the independent variable can change!)

10. Is Sam’s experiment fair? YES? NO?

11. Why is it important to change only 1 thing at a time?

12. If you don’t… then you won’t know what is causing your results. Independent Variable

13. For Example:

14. Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.

15. Identify the variables in this investigation.

16. What was the independent variable? • Ages of the students • Different ages were tested by the scientist

17. What was the dependent variable? • The time it to put the puzzle together • The time was observed and measured by the scientist

18. What was a controlled variable? • Same puzzle • All of the participants were tested with the same puzzle. • It would not have been a fair test if some had an easy 30 piece puzzle and some had a harder 500 piece puzzle.

19. Another example:

20. An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.

21. What are the variables in this investigation?

22. Independent variable: • Sizes of nails • These were changed by the scientist

23. Dependent variable: • Number of paper clips picked up • The number of paper clips observed and counted (measured)

24. Controlled variables: • Battery, wire, type of nail • None of these items were changed

25. One more:

26. The higher the temperature of water, the faster an egg will boil.

27. Independent variable – temperature of water • Dependent variable – time to cook an egg • Controlled variable – type of egg

28. Last one:

29. The temperature of water was measured at different depths of a pond.

30. Independent variable – depth of the water • Dependent variable – temperature • Controlled variable – thermometer

31. Designing Investigations

32. The greater the amount of soap in a soap and water mixture, the bigger a soap bubble can be blown. • Design an investigation to test this hypothesis. • Identify the variables • What exactly will be changed? How will it be changed? • What exactly will be measured? How will it be measured?

33. The farther a ball drops, the higher it will bounce. • Design an investigation to test this hypothesis. • Identify the variables • What exactly will be changed? How will it be changed? • What exactly will be measured? How will it be measured?

34. What do you think? Terry loves birds and wants to see as many as she can in her yard. She wants to know whether she is wasting money buying an expensive mixed seed, when a cheaper brand just arrived at her local store. She wonders… will the expensive seed attract more birds to her back yard? How would you advise her to find out if the expensive seed is better?

35. Terry’s Experimental Design

36. Terry’s Experimental Design $

37. Bellringer • A study was done to find if different tire treads affect the braking distance of a car. Independent Variable:__________________________________ Dependent Variable:___________________________________ Controlled Variable:____________________________________ 2. An experiment was performed to determine how the amount of coffee grounds could affect the taste of coffee. The same kind of coffee, the same percolator, the same amount and type of water, the same perking time, and the same electrical source were used. Independent Variable:___________________________________ Dependent Variable:_____________________________________ Different tire treads Braking distance The car Amount of coffee grounds Taste of coffee

38. Bellringer 8-15 1 - Patty Power Mr. Krabbs wants to make Bikini Bottoms a nicer place to live. He has created a new sauce that he thinks will reduce the production of body gas associated with eating crabby patties from the KrustyKrab. He recruits 100 customers with a history of gas problems. He has 50 of them (Group A) eat crabby patties with the new sauce. The other 50 (Group B) eat crabby patties with sauce that looks just like new sauce but is really just mixture of mayonnaise and food coloring. Both groups were told that they were getting the sauce that would reduce gas production. Two hours after eating the crabby patties, 30 customers in group A reported having fewer gas problems and 8 customers in group B reported having fewer gas problems. 1. What is the independent variable? 2. What is the dependent variable? 3. What should Mr. Krabs’ conclusion be? 4. Why do you think 8 people in group B reported feeling better?