during an experiment y is it important for the scientist to have control?

Answer 1

It is important to have a control because your data cannot be vaild if you tested two things but they were in different conditions. So controls are needed so a scientest can test one variable and find the effect of that variable on an experiment.

Answer 2

Say I want to test Supercide as a new drug against staph infections. So I have a dozen staph-infected mice, and give them all Supercide.

All the Supercide-treated mice die anyway.

Unless I have control groups, though, I don't reliably *know* whether Supercide is any good or not.
Maybe I gave them toxic levels of Supercide, and the drug killed them before the germs did. (Solution: test Supercide on healthy mice first, at different levels, and see if it's safe to use.)
Maybe the Supercide was effective, but the dose wasn't high enough, or I didn't give it long enough. (This was the problem when we were first using penicillin in clinical trials.)
Maybe the lab tech screwed up, and forgot to feed ALL the mice over the weekend, and every lab animal is dead.
Maybe this particular batch of lab mice are just really wimpy and weak, by sheer bad luck.
Maybe Supercide isn't effective against _this particular_ strain of staph. (Try another type, with a different virulence.)

Having several groups allows the scientist to sit back and say, "OK, it wasn't this factor, or this one, or this one....PROBABLY it was this." Then, you get to test and retest (replication)---the basis for good science.

Answer 3

becasue the experiment can go wrong; to control the manipulated variable in the experiment ; so that the scientist knows what changes for what reason.

Answer 4

They need a control to make sure there are no other factors that could be influencing the experiment other than the factor that is being tested and considered.

Answer 5

the undemanding theory is that in case you in basic terms regulate one variable (the autonomous variable) at a time and save each little thing else the same, you're able to be quite constructive that your result represents a metamorphosis in the based variable that became into brought about by skill of the substitute in the autonomous variable. in case you alter 2 variables, you may not be constructive which had an result on the effect. the least complicated occasion i can think of of is the previous "Which kind battery lasts the longest?" test, wherein different batteries are examined for length of existence, frequently making use of low-value flashlights. If categories of flashlights have been used, ought to you assume good outcomes from the test? No, because of the fact different flashlights consume ability at different expenditures. you may only substitute a million autonomous variable at a time to make specific of what's extremely happening. A variable is a few thing that may variety, or have different values. scientific investigations continuously contain 3 forms of variables: a million) The autonomous variable: it somewhat is the variable which you intentionally regulate, so which you will comprehend its values previously you start up off the test. as an occasion, in case you % to comprehend how the quantity of sunshine a plant gets impacts its improve, you will possibly desire to provide aome flowers different quantities of sunshine. because of the fact you're able to desire to % the quantities, you will comprehend the values of this variable previously you start up off the test. 2) The based variable:it somewhat is the variable you will possibly desire to degree to ascertain if it modifications for this reason of you changing the autonomous variable. because of the fact you will possibly desire to degree it to ascertain its values, you will no longer comprehend the values (i.e. the outcomes) previously doing the test. in the plant occasion you will possibly might desire to discover some way of measuring plant improve in the a number of gentle situations. 3) administration variables: those are the different variables which will impact the values of your based variable, so they might desire to be saved consistent to make it a honest try. In our occasion, issues like the temperature or the quantity of water might additionally regulate plant improve, so they might might desire to be saved consistent. those variables are called confounding variables.

Answer 6

To validate the experiment. If you do not have control of the situation how can you say that your findings were not just luck or circumstance?