|What is an Independent variable?|
|Question Date: 2017-10-31|
An independent variable is something that
scientists change in an experiment. A
dependent variable is something that changes
BECAUSE of the independent variable. In other
words, the dependent variable DEPENDS on the
independent variable. The dependent variable
is usually what scientists measure in an
For example, let’s say you wanted to do an
experiment to see what things make plants grow
taller. You predict that the amount of water a
plant receives will affect its height. So you
design an experiment where you plant two seeds:
one seed will be watered every single day, and the
other seed will be watered only once a week. You
measure the height of the plant every week for a
few months, and at the end of the experiment you
will see which plant is taller. In this case,
the amount of water is the independent
variable because that is what you're changing
in the experiment: one seed gets a lot of water
and the other seed only gets a little water.
The dependent variable is the height of the
plant, because you predict that the height is
going to change DEPENDING on how much water the
An "Independent variable" can mean a lot of
different things. In math, it usually refers to
a variable that does not depend on another
variable. The word "independent" generally
always means just that - think about the July 4th
holiday here in America - Its called "Independence
Day", where we decided we did not want to depend
on Great Britain for help anymore.
So lets say you have the equation in math:
Hope that helps!
y = x + 2
in this case, y is dependent on x for its
value, and depending on what x is, will always be
2 more than that. So in this case, x is the
independent variable, because it doesn't
depend on y to decide what it is.
Thanks for the great question.
One way that scientists learn things about the
world is by doing experiments. Scientists like
experiments because it allows them to carefully
control and measure important things they want to
In an experiment, the independent variable
is what the scientist has control over, it is the
thing that the scientist gets to decide. The
dependent variable is different, it is what the
scientist looks at or measures, but does not get
to decide. Typically, the scientist wants the
independent variable to change the dependent
Let’s think of an example.
Imagine you have made a new drug that you think
will make people’s memory better. To show that the
drug works, you have to run an experiment. The
independent variable would be whether you give the
drug to someone or not, as this is under your
control. The dependent variable could be a test
of how well they remember things. If those who
took the drug remember things better than those
who did not, the drug works!
Thanks again for your question!
Variables are things we measure. When
conducting an experiment or study, we are usually
interested in the relationships among these
variables. These relationships determine if a
variable is independent or dependent. An
independent variable DOES NOT change because of
the other variables in the study. On the other
hand, a dependent variable DOES change because
of other variables.
For example, we are interested in how your
height changes with time. In this study, there are
2 variables, height and time. You get taller as
time passes. However, time does not pass because
you get taller. Time will pass even when you stop
growing. In this study, time is the independent
variable and height is the dependent variable.
When you make a graph of something, the
independent variable is on the X-axis, the
horizontal line, and the dependent variable is on
the Y-axis, the vertical line. If one axis is
time, it's always the X-axis, the independent
variable. For example, you might measure how tall
your plant is every day or every week.
I've attached a
graph - on the X-axis it has how many hours
students studied for an exam. On the Y-axis, it
has their score on the exam. Do you think the
students got better scores when they studied
longer? I don't think the graph shows real
data - I think it's just an example of independent
and dependent variables.
But your question is a hard question, and there
are many ways to answer it. Wikipedia has a
description of dependent and independent
An independent variable is a variable that is
not affected by another variable, but which does
(or may) have an effect on another variable.
For example, suppose you want to measure the
effect of the temperature of a star on the
temperature of its planets. The star will have the
temperature that it does because of the star's
mass and stage of it's life - it has nothing to do
with the planets that orbit the star, if there
even are any. The planets will be much hotter if
they orbit a hotter star, though, because hotter
stars put out more light. In this relationship,
the temperature of the star is an independent
variable while the temperature of the planet is a
A variable is a way of representing a
quantity that changes. For instance, variables
you see every day may include the amount of water
you drink, or the number of hours you spend
An independent variable is a variable whose
change does not depend on the change of other
quantities. In an experiment, independent
variables are the quantities you change in order
to change other quantities. For instance, if you
were doing an experiment in which you want to find
out how the number of hours of sunlight exposure
affects plant growth, you might have two
variables: number of hours of sunlight given to
the plant per day, and the height of the plant. In
this case, the number of hours of sunlight is the
independent variable and the height of the
plant is the dependent variable, because
the change in the height depends on the hours of
sunlight, not the other way around.
At the heart of a scientific experiment, you
are testing how something responds to some form of
your input. When running an experiment, you repeat
it many times, changing one part every time and
observing what happens. This thing you're
changing is called the independent variable
(it's called a vary-able because you can vary
Everything you then measure is called a
dependent variable, because these depend on
the in(in meaning not)dependent variable. This is
vague so let's consider an example:
Imagine an experiment looking at flower growth.
Plant a bunch of identical seeds in separate pots
and let them grow next to each other with only one
difference among them.
This difference could be how much you water them,
then the amount of water each plant receives is
the dependent variable.
There can then be many dependent variables for an
independent variable, but examples here could be
how fast or tall the flower grows or what colors
its petals are.
When working with equations it is really
important to understand the difference between
independent and dependent variables.
An independent variable is a variable that
does not depend on anything else for it to
occur, while the dependent variable changes
based on the value of the independent variable.
This may sound a little confusing, so let’s
look at an example. Let’s say that we were
measuring how tall a plant grew over time.
In this scenario, time is an independent
variable because it does not depend on
anything else for it to occur, it just happens on
its own. This is different from the dependent
variable: the plant’s height. The plant’s
height changes as time goes on. The change in
height is directly controlled by time. The
dependent variable is always controlled by the
independent variable. I hope this answers your
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