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Variables 
The Variables Unit includes 4 investigations. In each investigation students conduct controlled experiments to test variables. 

Topics
Investigation 1 Swingers
Investigation 2 Lifeboats
Investigation 3 Plane Sense
Investigation 4 Flippers 
 

Investigation 1  Swingers  In swingers the students idetify the variables that may affect the number of swings (cycles) a pendulum makes in 15 seconds. Eventually they discover mass and release position don"t make a difference, only string length makes a diference. Through graphing we see a relationship between string length and number of swings. The shorter the string, the greater the number of swings, and, the longer the string, the less the swings.

Investigation 4  Flippers  In this last investigation students work with catapults to shoot waded up aluminum foil balls. They again try to control the variables in their experiments and discover relationships between distance shot, mass/ size of the ball, and amount of tension the lever is pulled back.
Investigation 1 Essential Questions and Concepts Learned

What is a pendulum and where have you seen one?
A pendulum is a mass supported at a point, free to swing.

What is a variable?
A variable is anything in an experiment you can change.

Does changing the variables mass, length, and release position make a difference in the # of swings?
A controlled experiment can be used to test one variable at a time to find length is the only variable to make a difference.

Is there a relationship between the length of a pendulum and the # of swings in a unit of time?
As the length of a pendulum increases, the number of swings in a unit of time decreases.

How can graphs be used to predict results?
A twocoordinate graph displays the outcome of a controlled experiment and can be used to make predictions.
Investigation 2 Essential Questions and Concepts Learned

What variables might affect the number of passengers a “lifeboat” can hold?
Placement of pennies, movement of water, type of cup, and size of the cup

What is the relationship between the capacity of a “lifeboat” and the number of passengers it will hold?
The greater the capacity the higher the # of passengers it will hold.

How do you find the capacity of a lifeboat?
Capacity is the volume of water a container can hold when completely filled.
Investigation 3 Essential Questions and Concepts Learned

What are the parts of an airplane system?
The parts are the pop sickle sticks, fishing line, duct tape, staples, straws, propeller, tail, and rubber band.

What variables affect the distance an airplane flies?
# of winds, length of rubber band, and the mass of the plane, and possible any flaws in construction

How do other variables affect the flight of a plane?
In a controlled experiment the experimental variable is changed incrementally to see how it affects the outcome.

What can graphs tell us about the results of a controlled experiment?
A twocoordinate graph can tell us the relationship between the experimental variable and an outcome.
Investigation 4 Essential Questions and Concepts Learned

What are the parts of a flipper system?
The parts are the base, the stick, and the ball.

What variables affect the distance a ball flies?
Flipper stick length, angle of base, mass, how far down the stick is pushed

What relationship do you discover between your experimental variable and your outcome?
The longer the flipper stick length, the less distance or height a ball flies. Or, The greater the angle of the base, the farther the ball flies.