Warm up 04-15-14

1. Warm up 04-15-14 • Question: Why does the tablecloth trick work? • Answer: • inertia (Newton’s 1st law) • Goal: I will explore inertia

2. Element of the day • 92 – Uranium – U • The first nuclear bomb was a uranium fission bomb, detonated over Hiroshima during WWII. The bomb had never been tested – partly because scientists were sure it would work, and partially because they only had enough uranium for one bomb. • The plutonium-based bomb dropped on Nagasaki three days later was tested in Alamogordo. • Naturally occurring uranium is 99.28% uranium-238 which cannot be used to make atomic bombs. Of the 0.71% that is uranium-235, 2/3 of it is removed in the refining process. What is left is called depleted uranium. • Depleted uranium is a very hard and dense metal and is used in armor piercing projectiles which catch on fire on impact. • Uranium was used in pottery glaze prior to the 1940s, but it’s a bad idea to eat from it, as uranium is a heavy metal that can poison you (it’s not that dangerous from a radiation stand-point, as it gives off mostly harmless alpha radiation). • It is only legal to own up to 15 pounds of pure uranium metal.

3. Warm up • calculators • Mythbusters • Tonight’s HW • Top half of pg 45 • Bring ch7 packet Agenda / HW