Hypothesis and Variables

Form a Hypothesis Hypothesis- a testable explanation of an observation. A hypothesis is NOT just an educated guess about what you think will happen. It must be able to be tested!

Form a Hypothesis We write the hypothesis in an If-Then statement ex: If the amount of fertilizer is increased, then the height of the plant will increase.

Variables & Controls A variable is anything that changes in a scientific experiment. The control is what you use to compare the results to in the end of the experiment.

There are 2 types of variables: Independent Dependent

Form a Hypothesis The Independent Variable goes after the “If” I.V. If the amount of fertilizer is increased, then the height of the plant will increase.

Form a Hypothesis The Dependent Variable goes after the “Then” If the amount of fertilizer is increased, then the height of the plant will increase. D.V.

Now You Try: If you spend more time studying, then your grade will improve. Independent Variable = Dependent Variable =

Now You Try: If you spend more time studying, then your grade will improve. Independent Variable = amount of time spent studying Dependent Variable = grade

Now You Try: If the temperature of the room is increased, then the bacteria will grow faster. Independent Variable = Dependent Variable =

Now You Try: If the temperature of the room is increased, then the bacteria will grow faster. Independent Variable = temperature of room Dependent Variable = bacterial growth

Variables & Controls A variable is anything that changes in a scientific experiment. The control is what you use to compare the results to in the end of the experiment.

2 Types of variables: Independent Variable: What you change. Dependent Variable: What changes because of the Independent Variable.

2 Types of variables: Independent Variable: Cause Dependent Variable: Effect

Independent Variable Independent Variable: What you change. Cause a.k.a Manipulated Variable Graphed on x axis

Dependent Variable Dependent Variable: What changes because of the Independent Variable. Effect a.k.a Responding Variable Graphed on y axis

Independent Variable vs. Dependent Variable Also Known As: Manipulated Variable Responding Variable Results: Cause Effect On a graph: X axis Y axis

After all of the data from the experiment is collected, then its time to organize the data.

Organize your data Put your data into a data table Independent Variable __________(unit) Levels Dependent Variable _______________ (unit) Trial 1 Trail 2 Trail 3 mean range

Organize your data Make the data table into a graph GRAPHS make it EASIER to see patterns in the data!

Organize your data How do you know what goes on each axis of the graph?

Organize your data DRY MIX Dependent Variable = Responding Variable = Y axis Manipulated Variable = Independent Variable = X axis

Parts of a graph Y Axis X Axis

Y Axis (Dependent Variable) X Axis (Independent Variable) Parts of a graph Y Axis (Dependent Variable) X Axis (Independent Variable)

Graphing: DRY MIX Dependent Variable Independent Variable

Any Questions????