If I something once it is a piece of information, data or clue.  However to be evidence, it may take many such observations, study, comparison with other works, or applying the scientific method to test and verify.  Sometimes it may be said the weight of the evidence, where you collect the data, literature, various studies, research, compare it and evaluate it for potential truths that is theorized from the review of the information. Sometimes one piece of evidence is typically enough to be accepted as fact, such as a birth certificate.  Other things like climate change require an assemblage of information, clues, observations and evidentiary findings,mand even then some do not believe.  If the sky was falling, they would only believe if it hit them on the head.  So what is believed to be evidence may be in part an individual determination.  Even as a scientist, there is probably some individual determination, and it is not necessarily enough to satisfy all.  Evidence is not necessarily fact or truth, but enough of it may lead to that end.

 Dear Mr. Raoni,

We can define the evidence as the reality that confirms or supports a phenomena. For example,  consider a phenomena like earthquake , what are the existing facts that confirms its happening? , The evidences would be: Faulted rocks , magnitude , intensity, the amount of surface destruction , historical repetition , or other realities which prove this phenomena. 

Researchers always looking for evidences to support thier conclusions when they study something in any field.

Best Regards

Dear Mr. Alkhafaji and Mr. Hansen

Thanks for answering. When you explain about some observation to confirm something, or about some fact that should be observed if your theory is correct, it`s not just some hypothesis about what happened?

In a example: Jewish people cannot eat pork because is writed in Alcoran, so for jewish people it would be an evidence of this impossibility?

another one: if you find some facts, like fauted rocks, magnitude, or something like that (i'm not an expert in this area, sorry), should it be an evidence. But what about if everyone in this area is thinking in a wrong way? 

Thanks again.

Dear Mr. Raoni, 

Scientific research is not based on field observations only, there are millions of researchers wrote millions of references for the last centuries. You must read what you can about the concerned case that you are studying , in order to fortificate your writings with references or to prove your new conclusions or interpretations. 

Best Regards. 

In time, Jewish people do not follow the Alcoran (Qur'an). The sacred book for the Jewish is the Jews call it Tanakh, a Hebrew acronym for the book which contains three sections: the Torah (the Pentateuch or first five books of the Old Testament), the Nevi'im (Prophets), and the Ketuvim (Writings). The Tanakh contains the 39 books found in the Christian Bible and called the "Old Testament." They also follow the lessons and rules present in the Talmud, which is considered the most important book in Judaism, since it tells them how to interpret and apply the laws found in scripture.

Religion apart, In this particular case, it is said in the Old Testament that an animal fits  to be eaten, if it does cud and have split hooves. So, pork do not attend to both requirement, and it can't be eaten. In the Book is the "law" they follow, so the word in this particular book are the evidence for this law. But, It's not said in the Old Testament that they can't eat pork, the evidence for this impossibility is in the specimens which belongs to the "pork" hypothesis: a pork has divided hooves, but doesn't cud. This are the evidence they gathered to say that a pork can't be eaten.

Cheers

Dear Vinicius.

Thanks for the retification. Unfortunately, it wasn't what I asked about. I think this question is above something I could search in wikipedia, so, if you have a question about what is an evidence and how can we evaluate it, please, let us know.

Dear Alkhafaji 

I know that Science is not just something testable, but it wasn't the question in fact. My question is concerned in: How can we evaluate some founding? Something in a paper is real everytime? If everyone say that it's correct, how can we evaluate if this is just a concernation or just a mistake made by a lot of people? I know that observation are not the field like only, but I think it's not the question.

Thanks again

Not at all, my friend. In fact I do understand what you are trying to say. Indeed,  if you read the second paragraph you will see that I tried to explain you, using your own example, the "meaning" of what is evidence in that particular case.

The first paragraph was just to introduce the theme, in a correct religious way !! 

hum... No, it's not the theme.