L#02%2008-18-11%20Ch1%20what%20is%20science%20Ch2%20Atoms

L#02%2008-18-11%20Ch1%20what%20is%20science%20Ch2%20Atoms -...

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Unformatted text preview: Biology 1103 Lecture #2 August 18, 2011 What is science? Science is a way of knowing What is science? Everything that is properly called Everything science has been based on experiments designed in accordance with scientific methods. Science relies on observation and experiments. observation and experiments Observation Something that cannot be Something observed cannot be investigated by science. by Ask a question? Define a problem by asking a Define question about the observation(s). observation(s). Hypothesis Then, propose what the answer to the question might be. This is a hypothesis. hypothesis To have scientific value, To hypotheses must be a logical and logical testable explanation. testable explanation. Experiment Do results support the Do hypothesis? hypothesis? If not, a new hypothesis and experiment must be designed. designed. The Use of Controls Question – Do herbicides affect the Question development of chicken embryos? development Hypothesis – Herbicides cause developmental Hypothesis abnormalities in chicken embryos. abnormalities Uncontrolled experiment Pierce egg. Test herbicide added in alcohol solution. Seal hole with wax and incubate. Potential sources of error 1. Does piercing affect development? 2. Does adding alcohol affect development? 3. Could the results be due to chance? 4. Could there be something wrong with the Could incubator? incubator? Controlled experiment Group 1 Experiment: herbicide in alcohol solution added to a number of herbicide eggs. eggs. Group 2 Control: alcohol solution added to a number of eggs. Group 3 Control: a number of eggs pierced but nothing added. Group 4 Control: a number of eggs untreated but handled in identical number ways. ways. Pasteur and “spontaneous generation” Pasteur’s experiments The use of statistics in science Nothing in science is ever finally proven! Nothing Every assertion in science is subject to change Every based on evidence. based Any scientific hypothesis must be falsifiable – Any open to negation through scientific inquiry. open Supernatural explanations lie outside the realm Supernatural of science and –thus- cannot be examined through the scientific process through What is the difference between a hypothesis and a theory? hypothesis What about scientific creationism? What Scientific creationism should not be labeled Scientific science for two reasons; science 1) It is not supported by any scientific It observations. observations. 2) It does not infer its principles from It observation, as does all science. observation, Nearly ALL scientists agree on the following: Nearly 1) The earth has a history of approximately 4.5 1) billion years. billion 2) Organisms have inhabited it for a greater part 2) of that time. of 3) All living things – including human beings – 3) have arisen from earlier, simpler living things. have Science is a process: Experimentation Controlled experiments use experimental groups Controlled and control groups to test a hypothesis. control Science is a process: Experimentation The experimental group is the group in an The experiment that experiences the experimental intervention or manipulation. experimental The control group is the group in an The experiment that experiences no experimental intervention or manipulation. experimental Science is a process: Experimentation The independent variable is the variable, or factor, The independent being deliberately changed in the experimental group. group. Science is a process: Experimentation The control group receives a placebo – a fake treatment The placebo given to control groups to mimic the experience of the experimental groups. – – The placebo effect is the effect observed when The placebo members of a control group display a measurable response to a placebo because they response think they are receiving a “real” treatment. In order to rule this out, the participants in the experiment do not know whether they are receiving a placebo or the experimental treatment. receiving Science is a process: Experimentation The dependent variable is the measured result of an dependent experiment. It is analyzed in both the experimental and control groups. and In a controlled experiment, the control group and experimental group differ only in the independent variable, so the results of the experiment provide evidence-based conclusions. conclusions. Drawing conclusions Confidence in scientific findings is increased Confidence by repetition of an experiment by other scientists. scientists. Drawing conclusions The sample size of the experiment can The sample strengthen our confidence in the results of the study. The sample size is the number of experimental subjects or the number of times an experiment is repeated. times In human studies, the sample size is the In number of subjects. number The larger the sample size, the more likely the results will have statistical significance. Statistical significance is a measure of confidence that the significance Statistical results obtained are “real,” rather than due to random chance. results Science is a process: Drawing conclusions The more experiments that support a The hypothesis, the more confident we can be that it is true. that A hypothesis that continues to hold up after hypothesis many years of rigorous testing may eventually be considered a scientific theory. theory Science is a process: Drawing conclusions Scientific Scientific theories are different than everyday theories. In science, a theory is a hypothesis that has never been disproved, even after many years of rigorous testing. ATOM The smallest particle of an element Examples: Hydrogen Carbon Nitrogen Oxygen Subatomic particles protons, neutrons, electrons – make up an atom Periodic Table Atomic number Number of protons. The number of protons equals the number of electrons. Atomic mass Mass of protons, neutrons and electrons (mainly protons and neutrons) electron shells: 2 Helium 2+8 Neon 2+8+8 Argon Stable 2 2, 8 2, 8, 8 ...
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