Does every scientific method begin with an observation?explain

It is not a rule that every scientific method should start with observing, sometimes you can predict the result of an experiment then observe if your prediction is right or wrong.

Explanation:

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.