1. The Scientific Method Variables (Physics Unit 1) What is a variable? What types of variables are there?

2. Variables Controlled (Do not change) Independent (Manipulated) Dependent (Responding)

3. Independent Variable (manipulated) The variable that is manipulated or changed in an experiment. The one you control and change. What you did. The treatment The Cause” Plotted on the x-axis on a graph.

4. Dependent Variable (Responding) The variable that responds to changes in manipulated variable. What you measure or observe What happened “The Effect” Plotted on the y-axis on a graph.

5. Controlled Variables Things we keep the same in an experiment, since we are not testing or measuring a response in them. Things you keep constant, don’t change during an experiment. The constants during an experiment.

6. Example of Identifying Variables in an Experiment A student was investigating the things that affected how candy dissolved in water. They wished to determine how the size of the candy pieces affected the time it took them to dissolve. IV - How big the pieces are (cause) DV - Time to dissolve (effect) CV - Amount of water -Temp of water -Time of stirring -How hard stirred -Type of container

7. 2 nd Example Does an electric motor turn faster if you increase the voltage? IV - Voltage of the electricity measured in volts DV - Speed of rotation measured in revolutions per minute CV - Same motor for every test Time motor is on Work

8. 3 rd Example How fast does a candle burn? ? IV - Time measured in minutes DV - Height of candle measured in centimeters at regular intervals of time (for example, every five minutes) CV - Use same type of candle for every test Wind--make sure there is none Temperature

9. Experimental Design How do you set up an experiment?  An experiment is designed to test if a hypothesis is correct or not.  An easy way to do this is make a comparison between two groups, the experimental and control groups.

10. Experimental Group: The group which is experiencing the treatment you are testing. The part of the experiment in which you change a factor (variable).

11. Control Group: is a standard against which any change can be compared and measured The group in which no changes are made. You compare this group against the experimental group.

12. Scientific Method: A formalized process of investigation designed to solve a problem, which incorporates the testing of a hypothesis.

13. The Steps of the Sci. Method 1 st Identify the problem -by asking questions 2 nd Educate yourself about the problem, research the problem. -library -reference books, magazines -ask the experts -internet, web sites, news groups

14. 3 rd Hypotheses, educated guess -always stated as an “if-then” statement 4 th Experiment -collect and record data

15. 5th Analysis of data -stat’s (average, mean, median, mode, range, etc.) -graphs

16. 6 th Conclusions - Was your hypothesis correct or not. - What does it mean? 7 th Applications of findings 8 th Communicate Findings