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A Review of Variables. Unit 1 Sixth Grade Science. The Variable Universe. What is a variable? A variable is anything that you can change that might affect the outcome of an experiment. Examples: In a car: body size and shape, tire size and shape, weight, fuel type, and color
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A Review of Variables Unit 1 Sixth Grade Science
The Variable Universe • What is a variable? • A variable is anything that you can change that might affect the outcome of an experiment. • Examples: • In a car: body size and shape, tire size and shape, weight, fuel type, and color • In a house: shape, number of rooms, wall colors. Floor type, number of windows
How do we determine the behavior of variables? • Experimentation – • A scientist will investigate the effect variable have by conducting an experiment.
More Terms to know • Controlled experiment – When you change one variable at a time and keep all the other variables the same. • System – A set of objects that is working together. • Pendulum – Any mass suspended on a string, rope, or other arm that is free to pivot from an anchor point • Cycle – A complete rotation; for example, one complete swing back and forth • Independent Variable – The variable whose value determines the dependent variable. This is found along the x-axis on a two-coordinate graph. • Dependent Variable – a variable that is determined based on the independent variable. This is found along the y-axis on a tow-coordinate graph.
More terms to know • Buoyancy – the ability to rise and float in a fluid. • Capacity – The maximum volume of fluid a container can hold. • Displacement – the fluid pushed out of a way when and object is placed in the fluid. (mass of the displaced fluid = the mass of the object placed in the fluid)
Investigation 1: Swingers • What were the variables for the pendulum? • The length of the string • The release position • The mass at the end of the string • Which variable affected the number of swings? • The length of the string • We found that as the length of the pendulum increases, the number of swings in a unit of time decreases. As the pendulum decreases, the number of swings in a unit of time increases. • How do we show the relationship between the number of swings in a given time and the length of the swing? • We use a two-coordinate graph, which also helps us make predictions.
Investigation 2: Lifeboats • What variables affected the number of passengers supported by a boat? • Size of the boat • Placement of the passengers into the boat • Where the passengers were placed • Condition of the sea • What did we find out? • The larger the capacity of a boat, the greater the number of passengers it can hold. • A two-coordinate graph can be used to make predictions.
Investigation 3: Plane sense • What are the parts of a model plane system? • Propellers, crafts sticks, rubber bands, straws, hook, the flight line, and the launch technique. • What are the variables in this lab? • The size of the rubber band • The number of winds on the rubber band • The number of paper clips carried by the plane • The slope of the line • The manner in which the airplane is launched • A two-coordinate graph displays the relationship between an experimental variable and an outcome.
Investigation 4: Flippers • What are the parts of the flipper system? • A flexible flip stick, a base, and the object launched. • What are the variables in this lab? • The mass of the object flipped • The angle of the flipper system • The length of the flip stick • Graphs can be used to look for errors, make predictions, and understand the relationship between a variable and an outcome.
Let’s practice • If you were trying to show the relationship between the number of pennies needed to sink a boat and the capacity of the boat, while other variable are controlled, which graph represents this? (X-axis is capacity, Y axis is number of passengers) Explain. A B C D
Let’s Practice • If you created a graph to show the relationship between the distance a model plane can fly and the mass of the plane, where all other variables are controlled, what would it look like? (X-axis is mass, Y-axis is distance flown). Explain your answer. A B C D
What to study?? • As you prepare for the exam, you should review the following items several times: • This PowerPoint • All your class notes • Your lab worksheets and notes Do not wait until the night before to begin studying…if you prepare a little each day, you will do well. This is a 40 point exam.