Bio 100 original presentationPresentation Transcript
BIO 100LECTURE: SCIENTIFIC METHOD
SCIENTIFIC METHOD Scientific inquiry involves:• Observing• Questioning• Experimenting• Analyzing and verifying information• Discarding of information
OBSERVATION• Leads to a question that may be descriptive or causal• Casual questions are the heart of scientific inquiry• Casual questions can only be posed after descriptive questions have been answered.• Another objective of Concepts in Plant Biology is to give you experience with science as an activity and scientific inquiry. Scientific inquiry involves observing, questioning, experimenting, analyzing and verifying or discarding of information. For the beginner, it is easiest to view scientific inquiry as a series of steps referred to as the scientific method.• The scientific method begins with an observation of nature or the physical world.• The observation leads to a question that may be either descriptive or causal.• For example, you may observe a giant redwood tree and wonder about the pathway water takes to get to the top of the tree.• This is a descriptive question. Alternatively, you may ask what causes the water to reach the top of the tree. This is a causal question. Causal questions are the heart of scientific inquiry but, often, can only be posed after descriptive questions have been answered.
QUESTIONING• Questioning can be applied to everyday situations.• Common occurrences provoke casual questions.• The scientific method can also be applied to everyday situations.• Such as:• You go out to start your car and the engine fails to turn over.• The light in the living room fails to come on when you flip the switch.• You always sneeze violently when you go to a particular friends house.• (Click mouse) Each of these common occurrences provoke causal questions: Why wont the light turn on or the engine start? Why do you start sneezing in this particular place?• Take a look at the following video clip about the scientific method.• Lets follow rest of steps of the scientific method to answer the latter question.
HYPOTHESIS• A reasonable possible answer for the observation• Unproven explanations• Must be consistent with previous observations.• nce you have a causal question, the next step is to generate a hypothesis – a reasonable possible answer for the observation. (click mouse)• Hypotheses are plausible but unproven explanations based on your previous experiences or experiences of others, by analogy, and by creativity. In our example, you know people with allergies start sneezing when they come in contact with something that causes the allergy.(Click mouse) You hypothesize that you must be allergic to something in or around that house. But what? The family has a cat and you know some people are allergic to cats. Perhaps its the cat. However, they also have rabbit, so perhaps its the rabbit. The family cultivates orchids. Maybe its the orchids. These are plausible explanations- or alternative hypotheses for your sneezing episodes. An important factor to consider when formulating hypotheses is that the hypothesis must be consistent with previous observations. If you have been in the presence of other cats and never had a sneezing attack, then the cat allergy hypothesis is not consistent with previous observations. (click mouse)
EXPERIMENTING• Test hypotheses by experimentation• Experiment is a set of manipulation or observationsof that nature that test a particular hypothesis.After posing alternative hypotheses, the next step is to test thehypotheses by experimentation. An experiment is a set ofmanipulations or observations of nature that test a particularhypothesis. For example, to test the hypothesis that you areallergic to rabbits you might visit other friends who have rabbitsthat roam the house freely. You would expect to start sneezingin these houses also, if you are allergic to rabbits. To test thehypothesis about the orchid allergy, you may visit the orchiddisplay at a local botanical garden or nursery and monitor yourresponse. If you were allergic to orchids, then you would expectto start sneezing under these situations.
ANALYZING AND VERIFYING INFORMATION• Compare observed results with expected results• From comparison make interpretations and conclusions• Note that in each of these "experiments", you have expected results, based upon the assumption that the hypothesis is correct.• Once the experiment is performed, the investigator can compare the observed results with the expected results. (click mouse)• From this comparison, you can make interpretations and conclusions. For example, if you go to another house with a rabbit and have mild sneezing attack, you would conclude that you are allergic to rabbits (hypothesis was supported) but that the severity of your allergy depends upon some additional factor (interpretation). This interpretation raises a new question, poses new hypotheses, further testing, etc. (click mouse)• Indeed that is the nature of science as an activity. If the hypothesis is not supported, that is, you do not sneeze in the presence of other rabbits, then you need to consider alternative hypotheses and follow through with the scientific method. Note that in both situations (hypothesis supported or not supported), you have learned something by applying the scientific method.
EXPERIMENTAL DESIGNA well designed experiment includes the following:• An experimental group (groups) and a control(s)• Each experimental and control group consist of many samples or individuals• The experiment is replicated (repeated) several timesScience only deals with observations and phenomenon that are testable by experimentationand cannot address questions of the supernatural or spiritual because they are not testable.Thus, experimentation is an essential part of science. As stated previously an experiment is a set ofmanipulations or observations of nature that is designed to test a hypothesis. Although we maythink of experiments as being conducted in the laboratory, they may also be done in the out-of-doors. Depending upon the nature of the question, nature may be manipulated or simplyobserved. For example, if you want to know the effect of fire on germination of pine seeds, youmight have a control burn (a manipulation). If you want to know what animal pollinates thesaguaro cactus flower, you would simply watch to see what the animals visit the flowers(observations).A well-designed experiment includes the following:1) An experimental group (groups) and a control(s)2) Each experimental and control group consist of many samples or individuals3) The experiment is replicated several times