In science, what is the meaning of a safety precaution, reliability and validity?

Below, an explanation for science safety precautions, reliability, and validity are provided.

Science Safety Precautions

Science safety precautions are procedures and regulations to follow in a laboratory setting to ensure that experiments are performed in a way that will not harm the scientist(s). Here is a list of safety precautions issued by the NSTA (National Science Teacher Association).

Reliability

Reliability refers to the repeat-ability or consistency of an experiment if it were to completed with a different group of people, in a different laboratory setting, with a different batch of the same ingredients, etc. Reliability is represented by a percentage. The closer the percentage is to 100%, the more reliable the experiment.

Validity

Validity refers to how well the results of a scientific study can be applied to a broader population than the study participants themselves.