The Way Science Works 110-1 mid-term Exam

( 10 points each )

1. When dried and harden, cement is rock-like, so it resists both compression and tension.

2. Arch structure has every internal part compressed when loaded from above.

3. Steel cable bridges only work when there are suitable anchor points on both sides of the river banks.

4. The name Sodium Chloride means when the compound is formed, Sodium loss electron and Chlorine gain electron.

5. Alum is used for cleaning water in large scale, the precipitate are non-toxic , so after collected and dried they can just fill the land.

6. Whether a dusk particle will sink is all about their equally received kinetic energy. The more massive one is jiggling less, so fluctuation can not undo the pulling of gravity so they go down.

7. The purpose of planting trees and keep environment natural in the water collecting area is to make sure the water being very clean and Methane (CH4) free, so that reduce the possibility of generating cancer causing CHCl3 during necessary chlorination procedure.

8. Releasing untreated domestic sewage will make river oxygen rich, help bacteria grow to release poisonous substance to damage ecosystem.

9. The reason of sending electricity in super high voltage is to overcome the limit of transmission distance.

10. Latent heat is the energy stored in substance, so that when material is compressed, heat is released and things warm up..