Variables

Investigation 1: Swingers

 

Students learn how to identify and control variables in an experiment with pendulums.  They systematically change the variables of mass, release position, and length of string to determine which variables will affect the number of swings in 15 seconds.  Students also learn to graph experiment results on a two-coordinate graph.

Word Bank:

bulletPendulum—a mass hanging from a fixed point that is free to swing to and fro
bulletCycle—any motion or activity that repeats itself
bulletVariable—anything that you can change in an experiment that might affect the outcome
bulletStandard—the basic procedure used in a controlled experiment, before changing any of the variables
bulletControlled experiment—an experiment in which one, and only one, variable is changed in order to assess its effect
bulletTwo-coordinate graphs—shows the outcome of a series of experiments when a variable is changed by steps

Study Questions:

bulletWhat is a variable?
bulletWhat is a pendulum and where have you seen one?
bulletWhat variables might affect the number of cycles the pendulum makes in 15 seconds?
bulletWhich variables made no difference in the number of swings?
bulletWhich variable did make a difference in the number of swings?
bulletIs there a relationship between the length of a pendulum and the number of swings it makes in a unit of time?

Investigation 2: Lifeboats

Students continue to identify and control variables in an experiment with lifeboats.  They construct lifeboats out of paper cups and then fill them with penny passengers.  They change the capacity of the boat to see how it influences the number of passengers the boat is able to hold.  Students graph their results on a two-coordinate graph.

Word Bank:

bulletCapacity—the greatest amount of fluid a container can hold

Study Questions:

bulletWhat variable might affect the number of passengers (pennies) a paper-cup can hold?
bulletIs there a relationship between the capacity of lifeboats and the number of passengers they hold?
bulletHow can you use a two-coordinate graph to predict the number of passengers a new boat would hold?

Investigation 3: Plane Sense

Students continue to identify and control variables in an experiment with planes.  They construct planes and measure the distance it will travel on a fishing line.  Then they chose one variable to change. They change their variable in increments and record their results.  Then they graph their results and come up with a written conclusion for their experiment.

Word Bank:

bulletSystem—a set of objects that work together

Study Questions:

bulletWhy is your plane and flight line a system?
bulletWhat variables had an effect on the FOSS planes?
bulletWhat do we call the two variables we graph on a two-coordinate graph?
bulletWhat is the manipulated variable and which axis is it graphed on?
bulletWhat is the responding variable and which axis is it graphed on?

Investigation 4: Flippers

Students design their own experiment with a catapult system based on what they have learned about controlled experiments.

Study Questions:

bulletDescribe the flipper system.  Why is it called a system?
bulletWhat variables might affect the distance a ball will fly?
bulletWhat is the relationship between the mass of a foil ball and the distance it flies?
bulletWhy do scientists conduct multiple trials of the same variable?

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