The Scientific Method.docx

The Scientific Method Biology is the study of living things, including their structure, organisation, chemistry and interactions with one another and their environment. It also includes the study of organisms no longer living, which only occurs as fossils. Branches of Biology **Good to know some exa...

The Scientific Method Biology is the study of living things, including their structure, organisation, chemistry and interactions with one another and their environment. It also includes the study of organisms no longer living, which only occurs as fossils. Branches of Biology **Good to know some examples** Botany Plants Zoology Animals Mycology Fungi Virology Viruses Microbiology Microscopic organisms – Bacteria, Viruses & Small Fungi Biochemistry The chemistry of life, including the structure of compounds and the reactions that take place in organisms Biotechnology Producing substances utilising microorganisms Immunology The study of immune systems Pathology The causes and effects of diseases Ecology The interactions of living things with each other and their environment Genetics Inheritance, its processes, patterns, and the structures involved Entomology The study of insects Marine Biology The study of the sea Palaeontology The study of fossils Epidemiology The effects and spread of diseases Bioengineering The hybridisation of biological structures and engineering to make useful products The Scientific Method The Scientific Method is a process of investigating an observation or phenomenon. (1) Steps of The Scientific Method **Need to know in-depth** Observation - an unbiased, accurate report of an event. Observations may be made directly using our senses (seeing, hearing etc), or indirectly using equipment e.g. microscopes or thermometers. Hypothesis – A hypothesis is a suggested explanation for the observation. In other words, a guess. Experiment – An experiment compares the results of two set-ups where there is only one difference, so that any difference in the result can be attributed to the difference in the set-up. Principles of Experimentation a. Information, called data, is collected from the two set-ups. b. The experiment is repeated many times. This is called replication. c. In one set-up, all of the conditions are set at optimum levels. This is called the control. The other set-up where one factor is changed is called the experiment. The factor that is changed is called the variable. There are two types of variables; Dependant: This is the variable we are examining Independent: This is the variable that is changed during the course of the experiment d. To be a fair test, there must be a large sample size. This produces more reliable results and reduces the risks of results being individual differences. e. Random selection prevents bias or unfairness. This means that test groups and control groups are chosen at random. Evaluation – The results of the experiments are checked to see if they agree with the hypothesis, which often involves complicated statistical procedures. Modification – If the results do not agree with the hypothesis, it has to be modified and the process of experimentation started again. If the results agree with the hypotheses, one can move on to the next step. Replication – This is an essential step in the process to ensure that the results are repeatable and true. The same results must also be obtained by other scientists. The results, as well as details of the methods used in the experiment, must be published so that others can carry out the experiment. Publication – Publication in scientific journals is the method of informing other scientists about a discovery. Before publication, the paper is sent to be checked by other experts in the same fields. This is called peer review. Theory – A hypothesis becomes a theory when it is supported by evidence. It must be tested many times and not disproved before it is elevated to the status of a theory. Law – If a theory has withstood long-term testing by many scientists, it can be called a law. Limitations of The Scientific Method **Don’t need to know all but good to be familiar with** Present Knowledge – The things we know about the natural world limit the hypotheses we can formulate. For example, until the middle of the nineteenth century, people had no real understanding of the causes of common diseases such as cholera. Miasma (bad air) was blamed. This idea was refuted when Louis Pasteur showed that microbes were the cause of many diseases. Pasteur’s discovery opened the branch of science known as microbiology. Basis of Investigation – The most realistic form of experimentation is on the organism concerned i.e., humans and animals. However, for ethical reasons, this is not normally allowed. For this reason, experiments are carried out in-vitro, which means in a Petri Dish or similar apparatus. This is not ideal as cells can behave differently when interacting with, or surrounded by, other cells. If these in-vitro tests prove positive, treatment may advance to human trials. Dishonesty and Bias – In 1998, a paper was published in The Lancet Journal claiming that there was a link between the MMR (measles, mumps, rubella) vaccine and Autism. As a result, many parents refused to inoculate their children with the MMR Vaccine. This resulted in a renewed outbreak of these deadly diseases. This paper was later found to be fraudulent. The author, Andrew Wakefield, hid many of the results which contradicted his findings. Despite the paper being debunked, some people still believe that there is a link between the MMR Vaccine and autism. Accidental Discoveries – Sildenafil (Viagra) was initially developed as a treatment for Angina, a heart condition involving chest pains. However, one of its side effects was that it caused erections in Males. Sales of Sildenafil, to treat erectile dysfunction, are now worth millions of Euros each year. Exam Questions 2014 – HL – Section B – Question 9 (a) (i) Give one example of a limitation of the scientific method. Accidental Discovery (ii) Where do scientists usually publish the results and conclusions of their investigations? Scientific Journals 2013 – HL – Section B – Question 9 9. (a) (i) Explain the importance of double-blind testing in scientific experimentation - Double-blind testing enables the experimenter to ensure that there is no bias on the part of the medical practitioner administering a particular drug to a patient. (ii) How does a hypothesis differ from a theory? A hypothesis is an educated guess based on an observation. A theory is a hypothesis supported by experiments 2012 – HL – Section B – Question 7 7. (a) In relation to the scientific method, explain each of the following: (i) Data- Information, observations, or results collected in the course of an experiment (ii) Replicates- Repeats of an experiment 2015- HL – Section B – Question 9 9. (a) (i) What is the purpose of a hypothesis in the scientific method? To form the basis for a prediction or to form the basis or starting point of an experiment (ii) Explain what is meant by double-blind testing in scientific experimentation. To ensure a test is fair and unbiased References Nau.edu.com