One of the reasons you had labs in your science courses in high school was to allow you to perform experiments that fostered your understanding of the scientific principles. The use of these science labs to gain understanding and insight of various scientific principles is an example of

Empiricism

Explanation:

Empiricism is an important principle of science. The principle focuses on need of real practical world experiments to validate scientific findings. Solely theoretical reasoning is not sufficient to form a strong base for understanding scientific logics. Testing & encountering, verifying them enable discovering & learning the best form of scientific knowledge. As, it is applicable in real world. For example : A student would better understand the rule of water absorption by a particular item - through really keeping it in water sometime & observing, rather than just listening & learning that.

Therefore, students have labs in science courses in high school, to allow them perform experiments that foster their understanding of the scientific principles