HELP!!!!! "controlled variable"

[Caropooh]

can anyone help us with DD12's science homework? She needs to say what the controlled variables are in this study. She has space for 4. The definition she has for controlled variable is: a variable that is not changed.
The study- A study was attempted to find if the length of the string in a string telephone affected its sound clarity.
We decided that the tin cans would be one variable. DH says the volume(because we can control it) would be another. Any ideas on what 2 more could be?

 

[frndofpooh]

How about the size of the hole in which you insert the string?

 

[Obi-Wan Pinobi]

The material the string is made out of? Or the thickness of the string?

 

[TheOtherVillainess]

That's what I was going to say, the type/thickness of the string and the size of the hole.

The type of cans used could also be a controlled variable.

TOV

 

[kimberlym4]

If the point of the assignment is to figure out whether the length of the string makes the difference in clarity, then she needs to control for other variables that may also be affecting clarity.

You're on the right track. The tin cans would be one variable you would want to control but I think you need to be more specific (e.g,, the size of the cans). Because if you don't keep the size of the cans constant while you vary the string length - then it could be CAN SIZE that is causing difference in clarity.

Other things you would need to keep constant (or other variables you would have to control) could be:
- the width (or diameter) of the string
- perhaps what the string is made of (twine vs. dental floss)
- maybe how taut you hold the string (vs. it being slack or loose)

Hope this helps your daughter.

 

[mrFDNY]

Perhaps what type of surroudings you have.E.g. Windy outdoors, big huge rooms,small bathroom, Also temps like cold outdoors or hot basement.

 

[TheOtherVillainess]

If the point of the assignment is to figure out whether the length of the string makes the difference in clarity, then she needs to control for other variables that may also be affecting clarity.

You're on the right track. The tin cans would be one variable you would want to control but I think you need to be more specific (e.g,, the size of the cans). Because if you don't keep the size of the cans constant while you vary the string length - then it could be CAN SIZE that is causing difference in clarity.

Other things you would need to keep constant (or other variables you would have to control) could be:
- the width (or diameter) of the string
- perhaps what the string is made of (twine vs. dental floss)
- maybe how taut you hold the string (vs. it being slack or loose)

Hope this helps your daughter.

TOV

 

[Caropooh]

Thanks for the help! We liked everones thoughts on this! I might even print up the responses so she can bring them in.
kimberlym4, DD says you must either be a teacher or a genius!

 

[pogo791]

If the point of the assignment is to figure out whether the length of the string makes the difference in clarity, then she needs to control for other variables that may also be affecting clarity.

You're on the right track. The tin cans would be one variable you would want to control but I think you need to be more specific (e.g,, the size of the cans). [ . . . ]

Other things you would need to keep constant (or other variables you would have to control) could be:
- the width (or diameter) of the string
- perhaps what the string is made of (twine vs. dental floss)
- maybe how taut you hold the string (vs. it being slack or loose)

You only have room for four controlled variables, and Kimberlym4 already gave them to you. Others I would add include
- the material that the tin cans are made of ("tin cans" is a generic concept)
- ambient noise (i.e. competing noise from the environment)
- atmospheric conditions (that was already mentioned by other poster)
- how close to the ear you hold the tin can (thus cutting out ambient noise)

 

[Longsx3]

Where the experiment is being conducted. Enviroment/location

 

[kimberlym4]

I teach at the college level - which means I'm not a genius or I'd have a job that made a lot more money!

I felt the need to give more info because the teacher in me it felt like it was cheating if I just gave her answers!

 

[Charade]

Each of the pieces that make up the tin can phone can be a controlled variable. The string(length and material), the can (size and material), the size of the hole and the "button" (size and material) used to anchor the string. All the others mentioned are much less controllable by the experimenter given the location (your house). Given that, I doubt you'll find as a much variance in sound clarity by changing environmental conditions or distance from your ear to the can as you would changing the other variables.

 

[Caropooh]

DD says ' WOW, thanks!!!!!!'