Intro unit: Nature of Science

1. Intro unit: Nature of Science • Science is organized commonsense • Hypothesis: An educated guess, based upon prior knowledge/experiences

2. Inference: logical explanation of an event based on observable characteristics (even without all of the information)

3. Controlled Variables – variables kept constant so as to not affect results ex: same plants, same soil, same temp. same light, etc. • Independent(Manipulated) Variable – variable changed on purpose (it’s the factor being tested) ex. plant 1= 100ml H20, plant 2=50ml H2O, plant 3=10ml H2O • Dependent (Responding) Variable – the results. It’s what happens as a result of the manipulated variable ex. plant 1 grew 4 inches, plant 2 grew 2 inches, plant 3 died [You can never have more than 1 independent variable, or you would not know which variable caused the results.]

4. Data: Information gathered through observation. • Qualitative data uses the senses ex. table is smooth, black, hard, rectangle, etc. • Quantitative data uses measurements ex. table top is 150 cm long and 30 cm wide

5. Steps in the Problem Solving Method: • State the Problem: {what are you trying to find out?} • State the Hypothesis {what do you think will happen? Why?} Test the Hypothesis {list materials & directions to use those materials.} • Record & Analyze Data {quantitative, or quantitative data; data tables, or graphs} • Draw Conclusions {multiple sentences: What did you learn, confirm, etc. Identify factors affecting the results, major concepts, questions the experiment generated, etc.}

6. Line graph shows change over time. Bargraph compares amounts Graphs & Tables – used to collect and analyze data (a picture of the results). Independent variable goes on the X-axis. Dependent variable goes on the Y-axis.Always give a graph a descriptive title, and completely and accurately label the X & Y axis.

7. Circle graph (pie chart) shows the parts compared to the whole.

8. Theory – a well tested explanation that explains a phenomena, based on many observations over a number of years (ex: Big Bang Theory) • Scientific Law – a tested and proven fact of nature. It happens that way every time. (Ex: Law of Gravity) • Scientific Model–a representation used to explain a concept that may be to small, large, far way, dangerous, etc. to be studied otherwise. (3-D model, picture, diagram, equation, etc.)

9. Scientific Notation - a type of shorthand in which a number is expressed as a value between 1 and 10 multiplied by a power of 10. Examples: 4 x 1021 is 4,000,000,000,000,000,000,000 3.141 x 1018 is 3,141,000,000,000,000,000

10. Primary Scientific Measurements • Length or Distance: Meter Stick, meters; m, cm, mm • Mass: Balance Scale, grams; g or kg • Volume: Beaker or Graduated Cylinder; liters; L or mL • Temperature: Thermometer, degrees celsius; ºC • Time: Clock, Calendar; min., s, hr, day, etc.

11. Sometimes 2 types of measurement are combined. Examples: Density: mass/volume 10 g/2 ml = 5 g/ml Speed: distance/time 10 m/5 s = 2 m/s

12. Metric System • Scientific measurements are made in metrics for the following reasons: • Recognized world wide • More accurate • Easier because it’s based on 10 (just moved decimals to convert)

13. Metric Prefixes • milli- m 0.001 • centi- c 0.01 • deci- d 0.1 • Deka- dk 10 • Hecto- h 100 • Kilo- k 1000 • To convert from a smaller to a larger unit, move the decimal to the left equal to the number of zeros. • To convert from a larger to a smaller unit, move the decimal to the right equal to the number of zeros.