wht 3 conditions must be satisfied for a scientific theory to be valid?

Answer 1

- A theory must be proposed and it must be proven by experiment.
- It must have results that can be proven by experiment time and time again; those results have to be reproducible.
- Other scientists must be able to perform the same experiment and get the same results; it must be held up to pier review.

This lets scientists propose ideas and test them then let others test them to make sure the experiment was done properly. If some unknown variable was introduced into the experiment then it would create different results. If other scientists worked on that and found the results didn’t match then they would know an error was made. More and more scientists would try to repeat the experiment to isolate the fault and so advance our understanding. This is the core of the Scientific Method (http://en.wikipedia.org/wiki/Scientific_Method).

The Cold Fusion theory is an example of this.

The scientists behind the experiment were able to create power from a chemical reaction that seemed to produce fusion of atoms. They had the experiment; they repeated it and they got the same results.

The problem is that no one else in the world could repeat the experiment and get the same result. The results were not reproducible and when subjected to pier review people found faults with the theory so it was considered to be an invalid theory.

When you run an electric current of a specific voltage through water you will have enough power to break the hydrogen and oxygen bond thus creating both gases.

This experiment was done and it was found to be reproducible by doing it again and again. When the experimenter told other scientists they tried the experiment and were able to get the same results so it was determined that water was a product of two hydrogen atoms and one oxygen atom; since you produced twice the hydrogen than the oxygen. This advanced our understanding of chemistry before we had the quantum model that would explain it. This experiment helped develop the quantum model because the model had to be developed that would explain ALL the possible results of chemical experiments. That is why quantum theory is the core to understanding chemistry and used by all chemists.

Answer 2

1) it must explain curren observations
2) it must make some sort of verifiable prediction
3) the results must be repeatable by other people

Answer 3

Dont forget: it has to be disprovable, meaning there is a way to test it and measure it accurately.