1. Scientific Method “How to think, not what to think”

2. The scientific method is an orderly and systematic approach to solving problems. It can be used to solve both scientific and everyday problems.

3. Steps of the Scientific Method  Observation  Develop a question  Form a hypothesis  Perform an experiment-analyze data  Draw a conclusion

4. An everyday problem…. Sara noticed that she needed a date for Friday night. She is at the observation stage of the scientific method.

5. She asked herself..could Ben be my date???? She is developing the question at this point.

6. She hypothesized (made an educated guess) that Ben would indeed be her date.

7. To test her hypothesis, she performed an experiment by asking Ben out on Friday. Dear Ben, I really like you. Will you go out with me this Friday? Love, Sara Circle One: Yes, No, or Maybe

8. Dear Sara I already have a girlfriend. So I will not be able to go out with you on Friday. Sorry, Ben However, upon analyzing the results of her experiment, she realized that her hypothesis was incorrect and concluded that Ben would not be her date.

9. Sara did not give up…..She started over with a new hypothesis. Maybe Josh will be my date.

10. Variable- factor being tested Independent Variable = What the investigator manipulates; the particular treatment or condition the investigator is most interested in the effects of Dependent Variable = What is measured or observed; the "data" collected in the experiment Experimental Group = Those participants exposed to the independent variable Control Group = Those participants treated just like the experimental group EXCEPT they are not exposed to the independent variable; the group with which the experimental group can be compared –the factor that responds in a predictable way

11. Describes how nature behaves but does not explain why nature behaves in that particular way. It is generally accepted to be true and can sometimes be expressed in terms of a single mathematical equation. Ex: Newton’s Laws of Motion

12. Theory: explains why nature behaves in the way described by a natural law A theory is more like a scientific law than a hypothesis. A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers. One scientist cannot create a theory; he can only create a hypothesis. Example: Einstein’s Theory of Relativity

13. Scientific method “situation” The drug lovastatin was suspected to reduce spasticity (stiffness) in patients suffering from AMN (a neurological disease). In a study, 50 patients were administered lovastatin while 50 other patients were given a placebo. What is the hypothesis? Identify the independent variable. Identify the dependent variable. Which group represents the control group?

14. Metric Conversions, Scientific Notation, and Dimensional Analysis

15. Scientific Notation Steps for converting: Put the decimal after the first digit and drop the zeros Ex. 123,000,000,000  1.23 To find the exponent, count the number of places from the decimal to the end of the number. Ex. In 123,000,000,000 there are 11 places therefore we write it as 1.23 x 10 11 Numbers less than 1 will have negative exponents Ex. 0.000001 will be written as 1 x 10 -6

16. Examples Convert: 0.005 5,050 0.0008 1,000 1,000,000 0.25 0.025 0.0025 500 5,000

17. International System of Units Built on a set of seven metric units, called base units Prefixes are added to the names of SI base units to represent quantities that are larger or smaller than the base units

18. SI Base Units Length – meter (m) Mass – kilogram (kg) Time – second (s) Temperature – Kelvin (K) Amount of substance – mole (mol) Electric current – ampere (A) Luminous intensity – candela (cd)

19. Metric Prefixes and Symbols Kilo – k Hecto – h Deka – da BASE Deci – d Centi – c Milli – m K ing H enry D ied B y D rinking C hocolate M ilk

20. Metric Conversions Practice Problems 1.100m = ____km 2.3m = ____mm 3.230cm = ____m 4.461mm = ____m 5.2500m = ____km 6.4500mg = ____g 7.2000g = ____mg 8.200g = ____kg 9. 23L = ____mL 10. 0.14mm = ____m 11. 1550mm = ____m 12. 4000mL = ____L 13. 1.4kg = ____g 14. 1452mg = ____g 15. 9.5m = ____cm

21. Derived SI units Area – sq. meter (m 2 ) Volume – cubic meter (m 3 ) Density – kg per cubic meter (kg/m 3 ) Molar mass – kg per mole (kg/mol) Concentration – moles per liter (M) Molar volume – cubic meters per mol (m 3 /mol)

22. Dimensional Analysis The technique of converting between units Uses: 1. Unit equalities – an equation that shows how different units are related (ex. 1cm = 0.01m) 2. Conversion factors – equation that always equals one (ex. 1cm/0.01m) *Multiply the conversion factor so that units you do not want cancel and the unit that you do want ends up on top

23. Unit Equalities (for dim analysis) 2.54cm = 1 in 12in = 1ft 3ft = 1yd 5280ft = 1mi 1.6km = 1mi 4.184J = 1 cal 1000J = 1kJ 1km = 1000m 1dm = 100mm

24. Homework Problems 1.64.5dm = ___ mm 2.91.2m = ___ km 3.96.5in = ___ yds 4.1.235ft = ___cm 5.8.95kJ = ___cal 6.34.5miles = ___m 7.52.3cm = ___ft 8.6.98m/min = ___km/hr 9.59.63cal = ___J 10.96.5kJ = ___cal 11.1year = ___ sec