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11/12/13. Jean Leon Foucault , a French physicist, proved, in the mid-1800s, that Earth rotates. We will see how he used a pendulum to prove that. I have three minute-long videos.
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11/12/13 • Jean Leon Foucault, a French physicist, proved, in the mid-1800s, that Earth rotates. We will see how he used a pendulum to prove that. I have three minute-long videos. • If Earth’s circumference, at it’s equator, is 25,000-miles, and it takes about 24 hours to rotate once, on it’s axis, wait’ll you find out how we use that knowledge to tell time. • More on next slide
11/12/13 • The Earth revolves around the sun at 30km/second. Let’s convert that into miles/second, and even calculate the circumference of Earth’s orbit, over a year. • Our solar system revolves around the galaxy at 220km/second. How many miles does it travel in one year? In fact, it takes our solar system 200,000 years to make one revolution around the galaxy. • More on next slide
11/12/13 • If light travels at 186,400 miles/sec. How far will it travel, in one-year? That’s called a light-year. • Our nearest neighboring solar system is 4.3 light-years, away. How far is that? • If the farthest object in our known universe is a flashing quasar star, 12-billion light years, away. How far is the farthest know object in the Universe? • More on next slide
11/12/13 • Got “lotsastuff” to write in today’s journal. • No homework.
Math for 11/12/13 • 30 km/sec. * 0.6 km in a mile = 18.0 miles/sec. • 18 mi/sec * 60 sec. = 1,080 miles/min. • 1,080 mi/min * 60 min. = 648,000 mph • 648,000 mph *24 hours = 1,555,200 miles/day • 1,555,200 mi/day* 365 days = 567,648,000m/yr
Math for 11/12/13 • 220 km/sec. * 0.6 km in a mile = 18.0 miles/sec. • 18 mi/sec * 60 sec. = 1,080 miles/min. • 1,080 mi/min * 60 min. = 648,000 mph • 648,000 mph *24 hours = 1,555,200 miles/day • 1,555,200 mi/day* 365 days = 567,648,000m/yr