Dependent Variables
Define Dependent Variables
Variables that may change when the independent variable changes. We measure the DV to see if it changes.
Define Control Variables
Control variables are kept the same in the experiment
Define independent variables
Variables that are changed on purpose in an experiment to see if they cause a change in the DV
Which variable is on the x axis?
Independent variable
How many independent variables should an experiment have?
1
I am running an experiment to discover which dish soap is the best for cleaning dirty pans. I test three different soap brands. What is the dependent variable?
The cleanliness of the pans
How many control variables can you have in an experiment?
As many as you need/can have
I am running an experiment to discover which dish soap is the best for cleaning dirty pans. I test three different soap brands. What is the independent variable?
Type of dish soap I use
Which variable is on the y axis?
Dependent variable
This is an if... then... statement that is sometimes referred to as an "educated guess". It is always testable.
A hypothesis
If I want to figure out whether adding more merits to a class increases participation, what is my dependent variable in the experiment?
Amount of student participation
I am running an experiment to discover which dish soap is the best for cleaning dirty pans. I test three different soap brands. Name at least 2 possible control variables?
Some Possibilities: Type of food in the pan, material of pan, type of sponge/cleaning tool, method for rinsing
I am running an experiment to find the effect of breakfast foods on my class performance. I eat cereal, oatmeal, eggs and no breakfast. What is the independent variable?
The different types of food I eat.
When labeling an axis, what 2 things need to be included
The name of the proper variable and the units of measurement
In an experiment which variable is the cause and which is the effect?
The independent variable is the cause
The dependent variable is the effect
I want to see how fast ice freezes in a freezer at different temperatures. I put ice in a freezer at 30 degrees, 10 degrees, and -10 degrees. What is the dependent variable?
Amount of time it takes for water to freeze
I am running an experiment to find the effect of breakfast foods on my class performance. I eat cereal, oatmeal, eggs and no breakfast. What are some things that you would need to keep constant?
Some Possible Answers: Amount of time studying, amount of sleep, class subject
I want to see how fast ice freezes in a freezer at different temperatures. I put ice in a freezer at 30 degrees, 10 degrees, and -10 degrees. What is the independent variable?
Temperature of the freezer the ice is in
Explain what the scale value is
The scale value is the amount that each tick mark or line changes by as you move along the number line
A scale value of 4 will make a number line read 0, 4, 8, 12, ...
What is the purpose of a hypothesis in an experiment?
To make a prediction that can be tested
I am testing the effect of amount of sleep on my quiz scores. I sleep for 6, 8 and 10 hours and record my quiz scores from the next day. What is the dependent variable?
My quiz scores
Why are control variables important?
So that we can be sure of the effect of the independent variable on the experiment. Without CV, other variables may change our experiment instead of only the IV
I am testing the effect of amount of sleep on my quiz scores. I sleep for 6, 8 and 10 hours and record my quiz scores from the next day. What is the independent variable?
Amount of time spent sleeping
Why is it important for the scale on a graph to have a consistent interval?
A consistent interval makes it easier to see how the numbers are actually related to each other.
(For example, we can easily see if the data is linear because it will form a line)
Why do scientists complete multiple trials during an experiment?
Multiple trials help scientists account for small or random errors that may occur.
By averaging multiple trials any error is minimized