Tools of Timekeeping: A Kid's Guide to the History & Science of Telling Time (Tools of Discovery series)
Format: PDF / Kindle (mobi) / ePub
From ancient civilization's earliest calendars and shadow clocks to the atomic clocks of today, the history of time measurement emerges in this interactive guide. The study of the evolution of timekeeping devices and the inventors of calendars and clocks is included and loaded with interesting facts and trivia. Fifteen hands-on activities help demonstrate humans' changing relationship with time over the centuries.
Tools of Timekeeping INT erodes rock and creates canyons, and an egg in a pan cooks over heat. Things change in the world, and we want to know how long it takes for them to change. When will the weather turn warm again? When will you arrive at school if you leave the house when the sun is on the horizon? How long do you have to wait before you can eat that egg?!? Tools of Timekeeping explores how mankind has used the changing world to track time and explains how you can use tools and supplies
happy to buy sticks that last only 50 minutes. Young boys who served as messengers were not allowed to sleep very much, so they would place a lit incense stick between their toes before they went to sleep. Aren’t you glad alarm clocks don’t work like this today! Some Chinese added several perfumes to their incense so that the aroma would change as the stick burned. If you started smelling, say, jasmine, you would know that 30 minutes had passed; once the air filled with a musky smell, you would
turns quickly at first, but then slows a little and finally stops. Maybe a bucket lands right under the water, but maybe not. If not, some water will splash past the bucket, and it will take longer to fill, which means more time will pass before the wheel turns again. Clocks rely on movement that is regularly timed and evenly measured; escapements make this possible. Manufacturers work in the same way on their production lines. If Galileo’s design for a pendulum clock showing the escapement.
parents for a quarter and a penny. Place the coins flat up on a table so that George (the sun) and Abe (the earth) stare at one another. Turn Abe counterclockwise one complete turn so that he faces the same direction; this equals one rotation of the earth on its axis. To include the earth’s movement around the sun, move Abe a bit counterclockwise around George without rotating Abe any further. Since Abe faces the same direction, he sees the same background he did to begin with. This counts as a
find out where the thief lives. • Airlines use GPS to make flight paths more efficient, saving time and money. Pilots can make safer landings because they know their exact position in the air. • Civil engineers use GPS to map and measure the earth, lay out paths for future roads, track forest fires, and guide bulldozers during construction. • Pet owners can have a tiny GPS tag placed under the skin of their animal so that if their pet runs away or gets lost, they can easily find them.