Equipment that I am using are a paper helicopter, a mm ruler, a clamp, stop watch.
I am using a paper helicopter as a test subject. Miss chose this design because it falls vertically in a right angel (to make it more accurate), as my research states that it will take more time to fall if it weren’t in a right angel. And it takes time to fall making it easier to time (more precise). A mm ruler is the most precise height measurement I have access to. A clamp is more accurate than a human hand because the hand moves and shakes, this means that the height is not the same. We do not want to use a wall as a stand for the ruler because the paper helicopter will smash in the wall repeatedly, stopping the spinning, making the paper fall quickly, so it is not accurate therefore we used a metal pole stand instead the ruler. the stop watch is for measuring a 10th of second which makes it more accurate.
My Independent variable is the length of the wings. The dependent variable is the speed of it falling from the same height. The controlled variables are mass, shape, height of the dropping, angel of dropping, the design, paper type…(etc.)
The controlled variables are named as that because they effect the independent variable that will by itself effect the dependent variable. Not surprisingly it is most of the time an overlook by researchers, but it is usually far more important than the dependent or independent variables. A failure to isolate the controlled variables, in any experimental design, will seriously compromise the internal validity. This oversight may lead to confounding variables (variables that cannot be eliminated) ruining the experiment, wasting time and resources. So simply you want to remove them or control them so that the things being tested are not affected. And if it is kept under control it is under your benefit, because its unchanging state allows the relationship between the other variables being tested to be better understood. Any change in a control variable in an experiment would invalidate the correlation of dependent variables to the independent variable, thus changing the results.
Writing about number reason number one, mass shall not be changed because it effects the experiment, it makes my falling rate quicker. And because the rules of experimenting allows you to have only one independent variable. Because science is about facts, these rules does not matter if they do not have an impact. So by changing the mass even slightly (in my experiment) will add or remove a bit of time that it takes to fall (paper helicopter) changing the speed, making your judgment harder and the best part is that your causality establishment is wrong because the experiment is done wrongly (the same reasons apply for the shape, design{it changes the experiment completely because you will change the average speed, forcing you to start the experiment from the beginning}, paper type{paper type is a bit tricky because it changes the design and the mass}).
When it is about height of the dropping. Even if you are calculating the speed, it does matter, even if the speed is equal to distance over time. Because falling objects do accelerate when falling, so you need to have the same height so that the helicopter does not accelerate or decelerate. Now the hard part is the angel, because science is about facts and maths is about fact, the angel matters. Because it will take a amount of milliseconds for each degree in order for it to become a right angel. That is why miss chose this design because it makes the falling angel a right angel to be more accurate. We control them so that we can prove that this speed was caused by changing the independent variable, ( in my case the length of the wings).
To control the variables is pretty much simple, all you got to do is to control every single thing stated in controlled variables by not changing it. If it were to be a more complicated experiment it will mean that we will need to stop chemical reactions and bunch of other stuff. And always remember Establishing Causality will never occur without EXPERIMENTING.
I will be throwing paper helicopters from the same shape and design. They will all be thrown from the same height (e.g. 1 m height). I will measure the average speed by using the formula Distance over Time. Then I will start changing the length of the wings to see what effect it has, proving my hypothesis.

June 23, 2016 at 10:39 am
Please, for clarity use the title of my classwork post here too.
also it is not enough to list the control variables and state that you must control them to maintain accuracy. You must explain how and the potential impact on RESULTS of not doing so.
July 14, 2016 at 8:13 am
Obai, I think you are ready to move on to the practical experiment now. It will definitely help you to identify the control variables.