Help identifying the control and variables in the "Go Green by Grwoing Green" project

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natalier71
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Joined: Tue Oct 06, 2015 3:41 am
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Help identifying the control and variables in the "Go Green by Grwoing Green" project

Post by natalier71 »

Please help us identify the control and variables in the "Go Green by Growing Green: How to extract Energy from Grass" project. If they can not be identified please assist us with modifying the project to include a control and variable, they are mandatory in the science fair. The kit has already been bought for $80 and the project approved so the project can only be modified not abandoned for a new one. We are waiting on the kit but are suppose to be working on the project now. Thank you!!!!
lynnsamuelson
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Re: Help identifying the control and variables in the "Go Green by Grwoing Green" project

Post by lynnsamuelson »

While this particular experiment does not have an obvious control and variables, you can modify the experiment to incorporate both of those. I would first start with determining the hypothesis and then the control. A good control would be a plant in which the growth rate is known. You can then compare the wheat, corn and oats to that (or use one of the three as the control if you can find the growth rate). Once you have a hypothesis and control, the variables are the differences that you are studying compared to the control.
roygoli
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Re: Help identifying the control and variables in the "Go Green by Grwoing Green" project

Post by roygoli »

Hi Natalier71,

cool experiment you've got there! In addition to the great advice you were just given, we could also help you identify the more specific variables...but first we must restate what they are to understand how they apply to your experiment :D

So, the dependent variable is simply the variable that you are measuring in your experiment. In this case it seems as if you are measuring the height of each plant over a span of 14 days. In other words a purpose of your experiment is to see if the type of growth or height of each plant over the same amount of time is dependent on the type of plant grown. So that means that the type of plant grown is your independent variable.

Your independent variable is what you're changing throughout your experiment to see if your dependent variable is affected by it. So, in this experiment you're changing the type of grass grown to see if it affects the height of each plant over the same amount of time.

Now, how about your controlled variables? These are the variables scientists need to have in order to develop a legitimate experiment. They are so useful that without them sometimes your results become insignificant and pointless. If any scientist wants their work taken seriously with real evidence, controlled variables are a must have....So...what is a controlled variable anyway? It is what you try to "control" or stay the same throughout your experiment. It's like a tool for eliminating loopholes.

Imagine if someone was measuring the effects of different liquids like milk, water, and coconut water on the growth of plants, but they placed two of the plants in bright sunlight and the others in the dark. The plants growing in the sun have an unfair advantage over the plants in the dark! We're not measuring the effects of light on plant growth, we're measuring the effects of type of liquid on plant growth. The plants in the sun may grow faster because of their location maybe leading the scientist to assume that they grew faster because of the seemingly advantageous liquid they were grown in, not because of the sun in their environment...which wouldn't be very accurate. The lighting in the environment should have been a controlled variable! It should have been kept the same for all the plants! So, what should you keep the same in order to make sure your data isn't sketchy? Maybe the environment of all plants? The amount of water you feed them? Can you think of any more?

Ok so now control groups. Control groups are another setup for your experiment sometimes without the manipulated variable. We compare control groups to our actual experiments to observe the difference between what normally happens and what happens when you effect your experimental setup with your manipulated variable. I really like lynnsamuelson's suggestion for a control group. If you know the growth rate of one plant and that plant doesn't grow at the same rate it usually does, you can question whether or not your plants are growing at the same rate they usually do.

I hope our advice was helpful! If you have any questions feel free to ask. We'd be happy to answer! :D
Here are a few links to help you out:
Variables:
https://www.sciencebuddies.org/science- ... bles.shtml
https://www.sciencebuddies.org/science- ... test.shtml
Similar Question:
viewtopic.php?f=31&t=14599&p=51620#p51620
Good luck!!
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