a chemical reaction a temperature change may occur because of the breaking or formation of chemical bonds that release excess energy. Since there is a change in temperature why wouldn't this reaction be considered a physical change instead of a chemical change ?

Laboratory experiments, observational field studies, and model-building are all examples of different forms of scientific investigations.  in what way do laboratory experiments primarily differ from other forms of scientific investigations?   a.  a laboratory experiment is the only accepted form of investigation within the scientific community.  b.  studies about how things behave in nature or studies involving very large objects are best answered through laboratory experiments.  c.  laboratory experiments involve the identification and control of variables.  d.  data can only be generated through laboratory experiments, not other forms of investigation.

Could we see a galaxy that is 20 billion light-years away?

What is an example of static friction