Scientific Method Flashcards
Biology
Study of living organisms
Different areas of biology
Botany - study of plants
Microbiology - study of small living things, such as bacteria
Zoology - study of animals
Ecology - study of the environment
• Genetics - study of genes
Biochemistry - study of chemical processes that take place in organisms
Anatomy - study of organs, muscles, structure of organisms
Cytology - study of cells
Immunology - study of immune systems of organisms
Marine biology - study of organisms in the ocean
The scientific method
a series of investigations to identify problems and explain these by means of carrying out experiments
Process of scientific method
Observation
Hypothesis
Experiment
Data
Conclusion
Theory
Principle
Observation
Noting or registering a phenomenon
Hypothesis
An educated guess
Experiment
A test to prove or disprove the hypothesis
Data
Information gathered from testing
Conclusion
Results of testing are summarised
Theory
A hypothesis that has been proven by experiments a number of times
Principle
a theory that has been proven by experiments many, many times
Osmosis experiment Hypothesis
Hypothesis: The visking tube has a more concentrated solution and so water moves across the membrane by osmosis.
Osmosis experiment control
Control: One of the tubes has water in it.
Osmosis experiment variable
Variable: One of the tubes has sucrose solution in it.
Osmosis experiment data
Data: Mass of both tubes is measured and recorded before and after the experiment.
Osmosis experiment conclusion
Conclusion: Water moves into the visking tube with the sucrose solution by osmosis.
Limitations of the scientific method
• The extent of our knowledge. (Forming a hypothesis and designing an experiment depends on the amount we know relating to our observations.)
Our ability to understand the results (If the results of an experiment are interpreted
wrongly, then faulty conclusions and hypotheses will be drawn.)
Accidental discoveries (New insights are often discovered accidentally which have contributed to the development of scientific thinking.)
Changes in the environment (Scientific methods may only apply to living things at one particular time. As living things are constantly evolving, hypotheses must constantly be changed. For example, global warming over the last several decades has impacted on plant and animal behaviour patterns.)
The basis of investigation (If an investigation is badly designed or improperly carried out it will not yield results that are as valid as they should be)
Where results can be published
Internet
Scientific journal
Newspapers/magazines
Random selection and why important
Random selection: To avoid bias. This is so that we don’t accidentally select a certain type of sample, as this will mean the results are influenced by the factor that is selected. If random samples are taken, then we can ensure that the experiment applies to all of the population, and the experiment is fair.
Replication and why important
Replication (repeating the experiment): To verify your results. A replicate is a repeat of an experiment. If it can be repeated, the results can be shown to be always true and not caused by some unknown influence.
Large sample size and why important
Use a large sample size: To ensure that the result was not only representative of a small amount of organisms. The larger the sample size, the less risk there is that the results are due to individual differences, rather than being caused by the factor that is being investigated.
Double blind testing and why important
Double blind testing (an experiment in which neither the tester nor the subject knows what treatment a given subject is receiving. In essence, it’s “anonymised” - but there is a record of who received what in the background. This way the tester cannot influence the experiment by consciously or unconsciously giving clues to the subject or otherwise. A placebo is a “fake” drug, or intervention, used in an experiment to set up a control): To avoid bias
Ways of keeping experiments fair
Random selection
Replication
Large sample size
Double blind testing
How to set up an experiment:
Variable This is what is going to change in your experiment. In almost all experiments, only one variable is tested, and all other variables are kept constant (in practice, this isn’t always possible, but it is desired because then it’s possible to know that it is the variable that made the difference to the outcome).
Control: Set up a comparison for your experiment. A control is used to provide a standard against which the variable can be judged. There should only be one variable between the control and the actual experiment.
Plan & design: Choose the reagents and instruments needed for the experiment and the method that will be used. Use the steps in the scientific method.
Safety procedures: Ensure that your experiment is safe by using precautions such as wearing gloves, wearing goggles, wearing a lab coat, tying up long hair, reporting accidents
Sources of error in experiments:
Miscounting
Misidentification of a substance or organism
Bias- eg sample not random
Ethical Issues:
Ethics refers to the concept of whether something is right or wrong. There are sometimes arguments as to whether the application of a scientific method is good or bad, such as cloning animals, or using placebo where it is likely that the active compound could make a difference to survival
Why is it important that scientists publish the results of their research?
So that other people can benefit from their research and continue the research further, aiding further scientific discovery
How can scientists avoid bias in scientific experiments?
Repeat the experiment a number of times and ensure that they get the same result each time
What is the purpose of replicates in scientific experimentation?
To ensure result is not biased
What is meant by the term hypothesis?
A possible untested explanation for observation
In relation to the scientific method, explain each of the following.
(i) Experiment:
(i) Theory:
(i) Experiment: This is designed to test the hypothesis, and will either support or contradict it.
(i) Theory: This is a hypothesis that has been supported by many different experiments.
Scientists investigated the effect of a certain mineral on the growth of wheat. Use your knowledge of biology and laboratory procedures to answer the following questions. Suggest a reason why the seeds used were all taken from one parent plant.
So that all results will have the same genetic make up.
Answer parts i) and ii) in relation to the scientific method.
(i) What is a hypothesis?
A hypothesis is an educated guess based on observations.
(ii) Why is a control normally used when carrying out an experiment?
.
A control is used to provide a standard against which the actual experiment can be judged
(b) Why is a control especially important in biological investigations?
It is important as we then have a standard against which the actual experiment can be judged.
If a scientist wished to determine the effect of a certain herbicide on weed growth she would include a control in the investigation. Suggest a suitable control in this case.
Water
The use of replicates is an important aspect of scientific research. What, in this context, are replicates?
A replicate is a repeat of an experiment which can verify if it is valid.
(e) Suggest where a scientist may publish the results of her investigations
They can publish them in journals, magazines, newspapers, the internet and on TV.
Explain each of the following terms in relation to the scientific method.
(a) Hypothesis:
(b) Control:
(c) Data:
(d) Replicate:
(a) Hypothesis:
This is an educated guess based on an observation.
(b) Control:
This is used to provide a standard against which the actual experiment can be judged.
(c) Data:
Data consists of measurements, observations and information gathered from experiments.
(d) Replicate: A replicate is a repeat of an experiment, which can verify its validity.
