The Way Science Works

Exam hints for 2009-Autumn mid-term examination

(1) What is the rationale behind the cross-bar structural reinforcement used in the bookcases?

(2) What are the superiorities using concrete/stone to build arch bridges and archway?

(3) Why is steel tougher than iron?

(4) Why must alum (Aluminum Sulfate) be added in the purification processes? What is the purpose of adding chlorine to tap water?

(5) Why is it not a good idea to discharge water into rivers without removing nutrients via treatment?

(6) Why do we need to convert the voltage output of generators into very high-voltage electricity for distribution?

(7) What cause the temperature increase in the microcosmic world?

(8) Try to explain what Resonance is. Write down some examples.

(9) Explain how dehumidifiers work.

(10) How can an amplifier magnify the amplitude of signals (of electrical current or water flow)?