Pasteur’s Experiment :s (1 Viewer)

[captain awesome]

In Pasteur’s experiment, (that led to the Germ Theory of Disease) what is the control? Is it the flask w/ the broth open to the air or is it the one w/the swan neck flask?

:s

thanks

 

[smartalec]

the control would be the flask with the straight neck. This is because it shows that bacteria can grow in the broth

 

[Nah_f_u_studies]

?
I thought the control would've been the s bend neck , im serious guys ..
the one with the s bend or swan bend is the control because it shows that there was no micro-organisms present in the flask in the first place and that micro-organisms dont grow in there .

 

[lil_pembo]

The s-bend is proving that the air holds the germs, disproving spontaneous generation. The straight neck is exposed to the air, showing that the air has the germs, and that the bacteria would have formed if it was exposed to the air. The s-neck is proving that the air can not get to the broth (as it is stuck in the tube) and therefore spontaneous generation did not occur otherwise bacteria would have grown in the s.

 

[Aquawhite]

Any control is a test of something that would occur under the initial/known conditions, with a known outcome. Because the flask with straight neck, as we all know, will lead to the development of microorganisms and germs within the broth... it is the control for the experiment. Pasteur's Swan Neck flask is the unknown and is being experimented upon to test his hypotheses.

Usually the control is selected simply by seeing which is the most rigorously controlled, however, you have to decide which is the control based on what the experimenter already knows and which test could lead to future knowledge.

 

[Nah_f_u_studies]

ohhh yeahh that makes sense
thx

 

[ruffshod]

my teacher told my class the control was the flask with a stopper in it because it produced no bacteria. Therefore you could compare the formation of bacteria from the open flask and bent flasks to the closed one with nothing in it.

?

iim so confused :|

 

[mariannebags]

dont panic too much it depends on how you phrase the investigation. If the hypothesis is that air is not enough to make the broth grow bacteria, then the control is the normal flask, and the test is the swam neck, although its true you could have three flasks and have another control with doesn't have either air or dust and air ( swam neck) or air and dust ( normal flask). its really up to how you set up thre investigation