Why is rain slightly acidic even without air pollution? Why is mercury used in a barometer? Why do clouds form at different heights in the atmosphere? Why does evaporation occur? Why does sea level rise when the climate warms? Why is the rain shadow effect important?
You take a pendulum clock to the moon. Assuming you do not change anything about the clock, will it still keep the right time? Why? A pendulum clock is taken to moon. Will it gain or lose time? Why is the invar used in making a clock pendulum?
2006年4月,新鑫佳苑工程10#楼工地发生一起起重伤害事故,造成一人死亡。现场在撤除现场物料提升机的标准节时,因吊笼钢丝绳受力过大被拉断,造成吊笼下坠,致使一名木工在吊笼内伴随吊笼从4层（约12m高）坠落至地面身亡。
some 400,000 people gathered in the tuileries gardens in paris to see the world's first manned flight in a hydrogen balloon. jacques charles and his assistant, nicolas-louis robert, ascended 1,800 feet into the sky accompanied by a mercury barometer, some sandbags, and a few bottles of ch...
Why does helium balloon rise in the air? Explain in words using physics principles why the pressure is lower at the right end of the pipe below. Why are objects with vast number of electrons normally not electrically charged? A mercury barometer always reads less than actual press...
Why is mercury used in a barometer? Why do seismometer oscillate back and forth? Why is stratigraphy important in archaeology? Why is geology important in geotechnical engineering? Why is uniformitarianism important to historical geology? Why is Alfred Wegener important? Why was Henry Cavendish's exp...
A mercury barometer always reads less than actual pressure. Explain why. What causes wind to blow? Why do weather satellites circle the earth at different altitudes? Why is a soft, underinflated football at sea level much firmer when it is taken to a high elevation in the mountains?...