Nature of Science

1. Nature of Science Last of unit… Technology defined, Safety wrap up, Measurement wrap up, Dimensional Analysis, Limits of Bio/Ethics

2. Technology • The making, modification, usage, and knowledge of tools, machines, techniques, crafts, systems, or methods of organization in order to solve a problem, improve a preexisting solution to a problem, achieve a goal or perform a specific function.

3. Perry

4. Precision vs. Accuracy of a measurement • Precision – same result repeatedly • Accuracy – correct result (on target)

5. Scientific Notation • Scientific notation is the way that scientists easily handle very large numbers or very small numbers. • For example, instead of writing 0.0000000056, we write 5.6 x 10-9. So, how does this work? • We can think of 5.6 x 10-9 as the product of two numbers: 5.6 (the digit term) and 10-9 (the exponential term).

6. Here are some examples of scientific notation.

7. The exponent of 10 is the number of places the decimal point must be shifted to give the number in long form. • A positive exponent shows that the decimal point is shifted that number of places to the right. • A negative exponent shows that the decimal point is shifted that number of places to the left. • In scientific notation, the digit term indicates the number of significant figures in the number. The exponential term only places the decimal point. As an example, • 46600000 = 4.66 x 107 This number only has 3 significant figures. The zeros are not significant; they are only holding a place. As another example, 0.00053 = 5.3 x 10-4This number has 2 significant figures. The zeros are only place holders.

8. Dimensional Analysis • Also called Factor/Label method • Uses conversion factors or ratios to change from one unit to another • MUST SHOW ALL STEPS WHEN DO THIS! • See worksheet with directions and practice…

10. The Nature of BiologyLimits of Biology • Science & Society • Ethics – define these in your own words From dictionary.com: That branch of philosophy dealing with values relating to human conduct, with respect to the rightness and wrongness of certain actions and to the goodness and badness of the motives and ends of such actions.

11. Examples: • *Pharmaceutical Studies (medicines – AZT for AIDS, “morning after” pill) • *animal testing (beauty supplies) • *stem cells (nerve cell transplants) • *genetic engineering (foods)

12. Limits of Science • Scientific approach cannot provide answers to subjective questions • Which color is best? • Cannot provide moral, aesthetic, or philosophical standards • Nothing is ever “Scientifically Proven”!

13. Glowing Mice = ethical?Green Florescent protein from jellyfish inserted into mice

14. A San Diego beach scene drawn with an eight color palette of bacterial colonies expressing fluorescent proteins derived from GFP.

15. Genetically modified crops • Pest resistance • Herbicide tolerance • Disease resistance • Cold tolerance • Nutrition – golden rice (high vit A) • ease of use -- seedless grapes, seedless watermelons

16. Vitamin A importance • vision (especially dark adaptation) • immune response • bone growth • epithelial cell growth and repair • embryonic development • regulation of adult genes.

17. Stem cell research • Stem cells: 1. have an infinite lifetime 2. are unspecialized 2 types: • Embryonic stem cells (in a fetus) • Adult stem cells