Could explain to me what is controlled experiment is?10 pts. for best answer. i need it very urgent.. ..tnx?

Question

please explain it clearly...tnx a lot ...hope you could help me through this college level biology...

Answer 1

An experiment designed to test the effects of independent variables on a dependent variable by changing one independent variable at a time.

Answer 2

I don't know if this is the right one for you:

http://192.107.108.56/portfolios/l/lautz...

http://www.geocities.com/spindlernd/scif...

Is it about science?

Answer 3

it means youre controlling the variables. its not random or anything.

Answer 4

Controlled experiment:

_A fair test

_One FACTOR is changed at a time while ALL other conditions are kept the SAME

_Two or more groups – one control, others with a variation of the test subject (these are called experimental groups)

_Done at least in 3 replicates/trials

Example:

PROBLEM:  How will the amount of fertilizer used  affect plant growth?

HYPOTHESIS:  Increased dosages of fertilized will cause greater growth in tomato plants.

INDEPENDENT VARIABLE:  The amount of fertilizer used.

CONSTANTS/CONTROLLED VARIABLES:

The seeds must all come from the same package.

All seeds must be planted in the same sized pots with similar soil.

All plants must receive exactly the same amount of water and light.

The temperature should be the same for all test plants.

More than one plant should be used in each test group (in case one type of seed grows better at this time of year than another)

SET UP:

Set one group as the CONTROL GROUP.  This group is not given fertilizer.

Set up two other test groups.  Once receives a certain amount of fertilizer and the other receives twice as much.

Hope this helps :)

Good luck!

Answer 5

Yeah I don't believe it is college level... BUT

Example: Which plant grows best in the required conditions?

Set A: Sunflower seeds, top soil, 1 cup of water a day, placed on window ledge.

Set B: Roses, same brand of top soil, 1 cup water, same location. Only one thing is changed.

The situation is controlled.  

Answer 6

A controlled experiment is when you have a control group and an experimental group and compare the results of your experiment on both groups to see the effect of a certain change.  For example, you can have a controlled environment:

Have pea plants grow in the lab where they receive 12 hours of light and 12 hours of dark and a certain amount of water.  This is your control group.  Then your experimental group could be pea plants that grow in 24 hours of dark or 24 hours of light.

Another example is drug testing.  The control group receives a placebo of a new test drug (let's say heart attack prevention pill...) and the experimental group receives the actual drug.  Then after X amount of time the results of the two groups are compared.  If the drug is effective then the experimental group should have a smaller % of heart attacks than the control group.

Basically, you want to hold all but one condition steady to see what the effect of that one condition is.  In the first example, the one condition is light.  Water, nutrition, etc. is held the same for both groups.  For the second example the drug is the difference.  There is an assumption with human subjects that if you have a large enough group differences in lifestyle, etc. are not significant therefore there is no need to keep your test subjects in a lab and make sure they all eat and sleep the same amount.

Hope this helps!