Lesson Plan: Variables
- Scientists differ greatly in what phenomena they study and how they go about their work. Although there is no fixed set of steps that all scientists follow, scientific investigations usually involve the collection of relevant evidence, the use of logical reasoning, and the application of imagination in devising hypotheses and explanations to make sense of the collected evidence.
- If more than one variable changes at the same time in an experiment, the outcome of the experiment may not be clearly attributable to any one of the variables. It may not always be possible to prevent outside variables from influencing the outcome of an investigation (or even to identify all of the variables), but collaboration among investigators can often lead to research designs that are able to deal with such situations.
- What people expect to observe often affects what they actually do observe. Strong beliefs about what should happen in particular circumstances can prevent them from detecting other results. Scientists know about this danger to objectivity and take steps to try and avoid it when designing investigations and examining data. One safeguard is to have different investigators conduct independent studies of the same questions.
- New ideas in science sometimes spring from unexpected findings, and they usually lead to new investigations.
- Investigations are conducted for different reasons, including to explore new phenomena, to check on previous results, to test how well a theory predicts, and to compare different theories.
- Hypotheses are widely used in science for choosing what data to pay attention to and what additional data to seek, and for guiding the interpretation of the data (both new and previously available).
- Sometimes, scientists can control conditions in order to obtain evidence. When that is not possible for practical or ethical reasons, they try to observe as wide a range of natural occurrences as possible to be able to discern patterns.
- There are different traditions in science about what is investigated and how, but they all have in common certain basic beliefs about the value of evidence, logic, and good arguments. And there is agreement that progress in all fields of science depends on intelligence, hard work, imagination, and even chance.
- Identifying variables in an experiment. Whether developing a scientific experiment, conducting a scientific experiment, or reviewing a scientific experiment.
- Make observations of surrounding environment, ask why or how, and develop the question into a hypothesis and experiment that can be tested and retested to verify results. Using controlled conditions that allows for collection of specified data.
Variables effecting the growth of a bean sprout
What brand of microwave popcorn has the least amount of un-popped kernels?
What type of bubble gum has the longest lasting flavor?
What type of computer chair is the most comfortable to sit in?
Amount of sunlight, amount of water, soil type/fertilizer
Manipulated: Brand/type of popcorn
Responding: # Kernels un-popped
C: Bubble gum
M: Amount of sugar, brand
R: How long flavor lasts
C: How they were built/manufacturer
M: Material used to make it
R: How comfortable the chair is
Design and conduct scientific investigations.
Specific Lesson Objective(s)
Design experiment and identify the manipulated, responding, and controlled variable targeted towards answering specific questions provided.
Introduction (5 minutes)
- Give overview of what we will do during class
- Worksheets, designing experiment/problem
- Discussion of manipulated, controlled, and responding variables
- Relate to previous lesson of experimentation through definitions. (Students measured how long it would take to eat a Jolly Rancher)
- Review the definitions.
- Manipulated: The variable that effects the outcome
- How the students eat the Jolly Rancher
- Control: The variable that doesn’t change
- Number of students who participated in Jolly Rancher Experiment
- Responding: The variable that is a result of the manipulation.
- How long it takes for the Jolly Ranchers to be eaten
Main Teaching Activity (30-35 minutes)
- Worksheet: Identifying Variables*
- Teachers will go over first problem as an example
- Finding 4 possible variables that could affect a bean seed sprouting.
- Students will work on rest of worksheet in groups
- Each group will be assigned a problem to be responsible for and present to the class
- Teachers will go over first problem as an example
- Recap the definitions based off the problems the class that were just completed
- Have students work on designing their own problem/experiment and identify the three types of variables
- Have students present their problems to the class and allow the rest of the class identify which variables are which
Conclusion (5 minutes)
- Review everything we have learned today as a class
- Assign Three Kinds of Variables* worksheet to be worked on for remainder of period and completed as homework.
*Worksheets are currently being processed into a document that can be viewed online - check back for update
Inquiry and the National Science Education Standards:
Michigan Curriculum Frameworkhttp://www.michigan.gov/documents/ScienceGuidebook_12929_7.pdf
Michigan's K-12 Curriculum and Standards