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Science for Kids/variables and control


my daughter has passed the first level of competition at her school and is now going onto the county level but one thing the judges commented on was she did not have her variables and controls "spelled out".  the problem is that we've spoken with several different people (including science teachers) and we keep getting different answers as to what would be considered a variable or a control in her experiment.

She prepared penne pasta with 4 different sauces.  the first had only butter.  the 2nd had an alfredo sauce.  the 3rd had marinara sauce and the 4th had marinara with added italian seasonings for more punch.  we tested 10 people.  the first test they were all blind folded and nose pinched.  the 2nd test the nose pinch was removed and we recorded their responses to any (or no) flavors.  

All food was prepared at the same time so everything should have tasted the same to all 10 people.

what would be our variables and what would be our controls in this experiment?????

First of all since you had human testing, do you have releases from each?  If any were children, do have signed releases from a parent?  If not, you need them!

Secondly, did you mAke sure that none were allergic to your ingredients?  You should have a materials list with all ingredients signed by each of the ten, specifically stating that they are not allergic.  

As for your control, this would probably be the plain pasta.  But since you did not test this, the next best thing you have is the buttered pasta.  To have a true control a taste test of unsaused pasta would have been your true control.  

The variable is the "tastiness" factor.  For this you are relying on human taste buds.  This adds to the complexity, since this adds to the variable nature of the sauce that is not "controlled" .  To do this correctly, you should go back to those ten people and have them blind taste the plain cooked pasta, with nothing on it.  But it too late for this.  

To do so after the fact would add an unacceptable variable.   But, it can and should be noted in the paper that goes with the experiment and the variable and control clarified.  

I hope this helps.  By the way what was the hypoyhesis and conclusion?

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Ralph Salier-Hellendag


Science Fair Judge for many years and experience with robotics, biology, chemistry, industrial processes, metalurgy and metal forming.


Science Fair Judge for many years and have helped several students get to state level competition. Most recently 2 of my students received state level awards and one went on to the nationals in Washington DC.

BA Archaeology - Anthropology
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