2. The gathering of facts by first-hand observation and experi-mentation and by reviewing the findings of previous investiga-tors;
3. Sifting, evaluating, and organizing the facts so that those bearing upon the problem indicate a possible answer or guess; and
4. Then by assembling and studying all the facts the scientist formulates a , a logical guess. Sometimes a hypo-thesis may lead to predictions. Testing such predictions may lead to the acceptance or rejection of the hypothesis.
All experiments should have a or check element. The control serves as a check because all the factors are the same as in the other experiment except the one being tested. If the
