1. Identifying Variables & Designing Investigations in the Scientific Method. Environmental Science

2. 3 Kinds of Variables in Environmental Science  Independent Variable – something that is changed by the scientist  What is tested  What is manipulated  What is controlled  Example: The more concentration of Carbon dioxide – the higher temperature in the atmosphere  Something else?

3. 3 Kinds of Variables in Environmental science  Dependent Variable – something that might be affected by the change in the independent variable  What is observed  What is measured  The data collected during the investigation

4. 3 Kinds of Variables in Environmental science  Controlled Variable – a variable that is not changed  Also called constants  Allow for a “fair test”  Any example we know in Environmental Science?  Any other law?

5. Let’s look for several exa- mples for Environmental Science First Example we have is in Environmental science:

6. Concentration of carbon dioxide is the independent variable. Measured temperature is dependent variable.

7. Now remember the very important step in our investigation! Let’s identify the variables in this investigation.

8. What was the independent variable?  Concentration of carbon dioxide  Different concentrations were tested by the scientist  Remember that temperature was fixed and thus constant!  So what is changing? ????

9. What was the dependent variable?  The temperature  The temperature was observed and measured by the scientist  Actually, the dependence is linear  And we have to investigate it!

10. Are you getting the idea? Or not!?! Another example in the Environmental Science:

11. An investigation was done with a closed water - fish system made from a closed container - aquarium. Different concentration of salt was used in the water. The growth of fish was checked by their size.

12. What are the variables in this investigation? Just be careful! But give your opinions!? Go! Please! Can we do it!?

13. Independent variable in Environmental Science:  Concentration of salt. Why?  Just because -  These concentrations were changed by the scientist. He can pick up anything he likes!  Can he?!

14. Dependent variable:  Size of fish  Of course we have more parameters to consider!  What is your answer?

15. Controlled variables:  Devices to measure parameters  None of these items were changed  REMEMBER WHAT IS UNDER CONTROL?  WHAT ELSE IS NOT CHANGING?

16. Let’s go to one more example in Environmental science!

17. The higher the temperature of water, the faster an egg will boil?! ARE YOU SURE ABOUT THAT? SHALL WE CHECK?

18.  WHAT WE HAVE IN THIS INVESTIGATION?  Let’s see:  Independent variable – temperature of water  Dependent variable – time to cook an egg  Controlled variable – type of egg

19. Last example for today in Environmental Science: Remember the previous examples?! What did you get from those examples?! Any idea?!

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

21.  LET’S SUMMARIZE OUR RESULTS:  Independent variable – depth of the water  Dependent variable – temperature  Controlled variable – thermometer

22. We are designing Investigations Basically we plan and do the steps of work to accomplish our final goal! Which was what?! Now do you see how all is connected and important?! We are designing Investigations Basically we plan and do the steps of work to accomplish our final goal! Which was what?! Now do you see how all is connected and important?!

23. 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?  WRITE IT AS A HOMEWORK!

24. 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?  WRITE IT AS A HOMEWORK !