Just one. Otherwise your margin of error will be too big. Make sure to have a control variable while your at it though.
3
ONE :)
Variables that remain constant in a scientific experiment are called controlled variables. These variables are not changed throughout the experiment to ensure that any observed effects are due to the independent variable being tested.
There are 2 variables and they are independent and dependant.
It is important to have controlled variables in a scientific experiment because it is the variable that remains the same it doesn't change. Its a consent & can be measured against.
It is easier to control independent variables
a scientific method to tell what stayed the same in an experiment
It depends what kind of experiment you do. For some you just need one. For others you may change two variables. In most cases you only change one
Independent and dependent does go under experiment on the scientific method.
In scientific experiments, the variables may be changed.
In a scientific method (or experiment), a dependent variable is one that changes throughout the experiment. These are the ones whose changes need to be recorded. Independent variables are those that influence the experiment, but do not change throughout the experiment and remain the same value.
A scientific experiment must be done by something that can show change. All of these can be variables.