the experiment of redi

THE EXPERIMENT OF REDI

Our plan

Objective of the experiment

We want to verify the falsity of the theory of the spontaneous generation, by reproducing the experiment of Francisco Redi.

Materials

three rather large vases of glass with cover.
1 piece of gauze in order to cover the vase
an elastic in order to fix the gauze on the vase
3 pieces of meat (of the same type), 3 sardines

Instructions

1. Put a piece of meat and a sardine in every vase
2. Close a vase with the cover, a vase with the gauze and leave the other one open.
3. Put the three vases in the open air, in a place repaired from the rain
4. Verify every 2 days, through approximately 3 weeks, what happens

FIRST TEST

date	vase #1 (open)	vase #2 (with gauze)	vase #3 (closed)	notes
16/01/02	/	/	/	Beginning of the experiment
14/02/02	the sardine has lost a piece of skin, the eyes are sunken, the meat has changed colour, (is darker)	the eyes of sardine are disappeared; the meat has become dark	the eyes of the fish are very deep set, the belly is greyer and opened; the meat is somewhere rose, somewhere darker	/
16/02/02	the fish has became mesh; in the meat there are some white dots, there’s a horrible smell!!!	the fish has became mesh; the meat is red with white dots, there’s a horrible smell!!!	The meat is dark, the fish very decomposed, there’s a horrible smell!!!	/

Conclusions

The meat and the fish have been decomposed by bacteria that, by fermenting, have produced strong smelling gases. We haven’t seen any flie around the vases, so we couldn’t verify if the theory of spontaneous generation is true of false. Probably the absence of flies depends on the very cold weather.
We carried out the experiment another time, in March, putting some grubs of flies, provided by a fisherman, around the vases.

SECOND TEST

date	vaso #1 (open)	vase #2 (with gauze)	vase #3 (closed)	notes
7/03/02	/	/	/	beginning of the experiment
9/03/02	The meat has a little changed colour, it is darker, the fish is a little skinned, its eyes are sunken. The grubs move fastly, all around the sardine; some enter in its belly	The meat has a little changed colour, is darker, the eyes of the fish are deep set. The grubs didn’t enter in the vase, had fallen down dead.	The meat has a little changed colour, it is darker, the eyes of the fish are sunken. We can’t see any grub around or over the vase	We put the grubs within the open vase and over the others two.
12/03/02	the sardine is disappeared! the grubs move around the meat	the decomposition of the meat and the sardine continues	the decomposition of the meat and the sardine continues	/
15/03/02	A grub has became red dark	/	/	/
18/03/02	All the grubs have became red	/	/	/
25/03/02	The first fly appear!	/	/	/

Conclusions

The grubs of flies ate the meat and the fish. After some days the grubs became red because they were transformed in chrysalises, from the chrysalises the flies were born. Ours is not a perfect reproduction of the experiment of Redi, because we used the grubs, but we can anyway assert that the flies can’t born spontaneously from the putrid meat and we observed their metamorphosis.


School site	Aristotle	Redi	Spallanzani	Metamorphosis	Microorganisms	"The tiny animals"