1. Scientific Method, Measurement, and Graphing

2. Scientific Method  An organized way of using evidence to learn about the natural world  A. Problem  1. observation- gathering evidence using the senses (sight and hearing)  Inference- a logical interpretation based on prior knowledge or experience

3.  A. Problem  Observation- gathering evidence using the senses (sight and hearing)  Inference- a logical interpretation based on prior knowledge or experience  B. Hypothesis  A proposed scientific explanation to a problem  “if…then” statement

4. C. Experiment  1. Two parts to every experiment  A. control group- doesn’t receive a variable  B. experimental group- receives a variables  2. Variable: the factors in an experiment that change (2 types)  A. manipulated variable (independent variable)- the variable that you can actually change  Only one variable can be changed at a time  On a graph, the IV is on the x axis  B. Responding variable (dependent variable)- the variable that will change or respond to the IV  3. Constant (controlled variable)- things that remain the same in an experiment

5. D. Record and Analyze Data  Info collected during an experiment  2 main types of data:  1. Quantitative data- expressed as numbers obtained by counting or measuring  2. Qualitative data- descriptive and involves characteristics that can’t be counted

6. E. Conclusion  Summary of experiment, using the data to determine whether a hypothesis is supported or not  A conclusion must have 3 things  Restate problem  Briefly summarize results  Does results support hypothesis?

7. Example:  Do bacteria grow better at higher temps?  Hypothesis: If the temp is higher, then the bacteria will grow better  Independent variable: temp  Dependent variable: bacteria growth  Constant: same type of bacteria, same type and amount of agar  Control: bacteria at room temp

8.  Theory: a well tested explanation that unifies a broad range of observations. Theories can change.  Law: ideas that have been tested many times and accepted as true. Does NOT change.

9. II. Measurement  Metric system (based on units of 10) litter Kmhecto deca meter dm m cm mm gram (Unusually) King Henry Died Drinking Chocolate Milk

11. Metric conversion examples  1. 100 L = ? mL  2. 2.5 m = ? km  3. 8 mg = ? g  4. 5.5 cm = ? mm  5. 4 kg = ? g

12. Metric conversion examples  1. 100 L = 100,000 ml  2. 2.5 m = 0.0025 km  3. 8 mg = 0.008 g  4. 5.5 cm = 55 mm  5. 4 kg = 4000 g

13. Measurement  A. Length  1. Instrument = rulers, meter stick  2. Units = km, m, cm, mm  B. Mass- amount of matter in an object, doesn’t change  Weight- measure of the pull of gravity, changes  1. Instrument = triple beam balance  2. Units = kg, g, mg

14. C. Volume  The amount of space an object takes up  1. Volume of a liquid:  A. instrument = graduated cylinder, beaker  B. units= l, ml  Meniscus- curve in graduated cylinder  2. Volume of a regular-shaped solid:  Formula: length x width x height  Unit = cubic centimeter (cm³)  3. Volume of an irregular-shaped object – water displacement

15. E. Temp  1. Instrument: thermometer  2. Units: degree Celsius  3. freezing point of water = 0ºC32ºF  Boiling point of water = 100ºC212ºF  Body Temp = 37ºC98.6ºF

16. F. Density  Mass per unit volume  1. Formula- mass/volume  Unit: g/ml  2. Ex: If the volume of a rock is 2 ml and the mass is 4 g, what is the density?  4 g/ 2ml = 2 g/ml

17. III. Graphing  A. Circle/Pie Graph- shows parts of a whole (100%)  Ex: Gases in the atmosphere  Nitrogen= 78%  Oxygen = 21%  Trace gases = 1%

18. B. Bar Graph  Compares data - usually 1 quantitative, 1 qualitative data sets  Example: Number of students taking a foreign language 58 – Spanish10 - German 92 – French9 – Italian

19. C. Line Graph  Used to show change over time - 2 quantitative data sets Temp (C)Number of bacterial colonies 1012 2025 3055 40100 5082

20. Things to have on a graph:  1. Title  2. X and Y axis labeled  A. IV on X axis  B. DV on Y axis  3. numbers on axis evenly distributed  4. Key if necessary