Scientific Method to Interpret a Scientific Investigation Flashcards
Hypothesis
An informed guess about a causal relationship that is generated by observation and initial data collection.
Identify a relevant hypothesis based on a given investigation
A valid hypothesis is testable and has the potential for being proven wrong. Scientists develop hypotheses only after they begin to have ideas about relationships. Can be background research on a topic. Hypothesis is a guiding idea to develop a strong investigation or experiment. During the investigation , the hypothesis will be rejected or accepted based on evidence collected from the investigation.
Experiment 1
Suppose a scientist wanted to determine the best conditions for germinating seeds. Scientist hypothesize that seeds need to be in moist soil for them to germinate, based on their investigation, the hypothesis will be supported or rejected based on the data. An invalid hypothesis is modified or replaced. Then the modified or replaced hypothesis is then tested by further experimentation.
Scientific hypothesis
A prediction of what will occur in an experiment based on previous research.
Describe a simple or experimental design to test a hypothesis
Scientific investigations collect experimental data to support or reject hypotheses. To test a hypothesis, an experiment must be set up in such a way that the data is accurate and valid.
Consider an experimental design
Scientists are investigating the effect of water on germinating seeds. Their hypothesis is that water is necessary for germinating seeds. They have 100 seeds. Fifty seeds receive 25 ml of water each day, and 50 seeds receive no water. All other conditions such as the amount of sunlight, temperature, soil conditions , and plant type are kept the same for every seed in the experiment. Important to review the methodology of any investigation to determine if its valid. The experiment only manipulates the water added to the seeds. Water is the independent variable. Observations on whether seeds germinate is the dependent variable and all other aspects that might affect the experiment are kept constant. These are controlled variables (sunlight, temperature, soil, plant type).
Sample size of experimental design
Important aspect of an experimental design is sample size and the use of multiple trials. The sample size of each experimental group includes 50 seeds. One seed would not be a good sample size because it could be defected. Having more seeds gives scientist more data to analyze. The scientist should also repeat the experiment multiple times to make sure they obtain similar results.
Identify, Independent Variables
Variables are the parts of the experiment that could be changed or manipulated during the experiment. In the example of seed germination there are 3 types of variables: independent, dependent, and control. Each experiment should only manipulate one variable: the independent variable. Ex: type of concentration of a medicine.The independent variable is plotted on the x-axis of a graph. In the seed germination example the water was the independent variable.
Identify Dependent Variables
The dependent variable is what is measured after the independent variable is changed. It is the observed condition that responds to the manipulation of the independent variable. Examples of dependent variables include growth or response. The dependent variable is plotted on the y-axis of a graph. In the germination of seeds example the dependent variable is the observation of the germination of the seeds.
Experimental Controls
All other variables should be kept the same in an investigation. These are called the “controlled variables” such as temperature and humidity. All other variables, such as the amount of sunlight, temperature, soil conditions, and type of plant, should be the same or controlled for all seed experiment. Controlling all other variables helps to establish a causal relationship between independent and dependent variables.
Determine whether experimental results or models support or contradict a hypothesis, prediction or conclusion
After conducting investigations, scientists analyze their data to determine possible conclusions. Scientists accept or reject their hypothesis or prediction based on the data to form a conclusion. Conclusions are based on evidence and subject to scrutiny by scientists. Scientists can submit their evidence to professional journals where investigation and data are reviewed. Only the most reliable experiments and data will pass through the review process and be published. Also called a peer review.
Seed germination experiment
Evidence supports hypothesis that seeds need water to germinate. This is because more seeds germinated 27 seeds when water was added than without water 5 seeds.
