2006-09-14 09:38:54 · 9 answers · asked by Nessa 1 in Science & Mathematics ➔ Physics
The reason to only test one variable at a time is so you know the exact affects of that one variable. If you test two variables, and get a certain result, you don't know which variable to attribute the change, or if they both affected the results.
To test more two variables, the most thorough way is to have a control, test each variable by itself, then test both of them together. This gives you both first and second order affects.
2006-09-14 09:43:45 · answer #1 · answered by bordag 3 · 1⤊ 0⤋
Because your'e not going to learn anything about a combination of 2 or more variables until you have tested each separately so you know which effect is caused by each and not a result of the two working together.
2006-09-14 16:49:38 · answer #2 · answered by pessimoptimist 5 · 0⤊ 0⤋
An "effective" test should ultimately reveal the effects of only ONE variant on the item at at time because each variant has a different effect on the item when combined with other variants.
Take water-evaporation, as an example.
When you apply only ONE variable (either heat or wind) you can establish the effects more precisely. Combining heat with wind, the results will change, leaving more of a window of error.
2006-09-14 16:50:09 · answer #3 · answered by Anonymous · 0⤊ 0⤋
sometimes an example needs to be used. now is that time. say you were testing the way a colored filter colors a flashlight beam. Now, say you want to have the variable be the color of the filter. If you add a second variable in between tests, such as lighting of the room, you may have two completly contradictory results.
2006-09-14 16:46:22 · answer #4 · answered by arctic storm 1 · 0⤊ 0⤋
One very important reason: to be able to conclusively compare the effects of changing one variable.
2006-09-14 17:12:59 · answer #5 · answered by msi_cord 7 · 0⤊ 0⤋
Because an experiment can only be 1 variable.
If you had two or more you cannot decipher if it was one or a combination of changes or results that occurred.
2006-09-14 16:43:18 · answer #6 · answered by beedaduck 3 · 0⤊ 0⤋
Sometimes the joint effects of several factors has to be investigated, then "2 to the k factorial designs" are used.
I have to review the subject myself, so to find out more on the subject look up factorial designs.
2006-09-14 16:49:24 · answer #7 · answered by Anonymous · 0⤊ 0⤋
so that any results that come from that experiment can be attributed to one variable and not the combination thereof.
2006-09-14 16:41:45 · answer #8 · answered by AD 2 · 1⤊ 0⤋
because if there is more than one variable, you don't know which one affected the outcome.
2006-09-14 16:46:48 · answer #9 · answered by Nikki H. the wizard 3 · 0⤊ 0⤋