“The Process of Science” Scientific Method: “The Process of Science”

SCIENCE is a method of investigation, based on : - observation - testing of hypothesis - includes measurement and experimentation - theory building there are clear rock layers in the Grand Canyon

what observations can be made what observations can be made? what questions do these observations lead to? (picture from Grand Canyon national park)

observations must be objective, not subjective - the opinion of the observer shouldn’t affect observations that are made Great Sand Dunes National Park

a hypothesis is an educated guess - can be tested by : - measurement - experimentation -> dependent variable - variable that that is affected ->independent variable - variable that is controlled

the results of experimentation and measurement lead to theory building a theory is a tested scientific concept that explains natural occurrences - an example is the Cell Theory cells make up all living things, cells of human blood are clear in this image All living things are made of cells, all cells come from preexisting cells, cells are the basic building blocks of life

Communication is necessary in science - scientific findings must be communicated to other scientists - other scientists must be able to : - repeat the work and get the same result - critically analyze the work - use the results in their work journal of invertebrate biology cover

ethical considerations limit experiments that can be done in science - is it ethical? is the same question as - is it right?

guidelines for experiments that involve humans include : informed consent - subjects should know that they are participating in an experiment subjects should not be at an increased risk of harm from their participation

Case Study : Tuskegee Study of Syphilis 399 men with syphilis were recruited and told that they would be given a new treatment for syphilis instead, they were not treated at all and just observed to see how the disease would progress untreated study lasted from 1932 - 1972 in 1947 penicillin was shown to be effective in treating syphilis but was not given to the infected men

28 of the men died directly of syphilis 100 died of related complications many of their wives and children were infected syphilis bacteria, sites of infection

guidelines for experiments that involve animals include : lawful acquisition of animals animals should be kept in humane conditions pain during experiments should be minimized Rat hippocampal neurons on silicon pillar

scientific knowledge changes as new evidence is found Tyrannosaurus rex was a scavenger, not a predator, according to new evidence new skeletons new technology to look at old skeletons

personal beliefs must be put aside by scientists conclusions must be drawn from available evidence only - Dr. John Horner : “I don’t care if T. rex was a scavenger or a predator!” - objectivity is necessary for good science to be done

most lab safety rules are common sense : dispose of broken glass properly always tell the teacher about a problem tie long hair back, no flowing sleeves use fume hood for chemicals that give off dangerous gases wear closed-toe shoes pour acids into other solutions (in case of splashing) dispose of waste materials properly waft, don’t sniff