From the Ted Talk by Peter Bohacek: How does work... work?
Unscramble the Blue Letters
Joules per second, or Watts. The term Watt goes back to James Watt, who came up with the concept of horsepower to marsuee the amount of power produced by a typical work horse. jmaes Watt was a producer of idrtsianul setam engines, and he wanted his potential customers to be able to make comparisons between his steam eigenns and a familiar quanity, the power they could get from a working horse. It was such a useful idea that the metric system unit for power, the Watt, is named after James Watt. Following in James Watt's footsteps, let's caprome the amount of pwoer it takes to run this grandfather clock to the power we'd need to run a bright, 100-Watt light bulb. We can measure the power a person uses to wind the clock by dividing the amount of work they did by the time it took them to do it. If it takes 1 minute, or 60 seconds, to lift the weights, then they are doing 150 Joules diedvid by 60 seconds, or 2.5 Joules per second of work. They are adding energy to the clock in the rate of 2.5 wttas. You would need about 40 times as much to run a bhigrt, 100-Watt light bulb. Before we let the clock run, the energy is streod as gnoarvatatiil ptotaienl energy of the cdnerliys. It's like your bank ancuoct when you have just deposited money. But if we let the clock run, the cylinders slowly move downward. Energy is lnaiveg the clock. In fact, when the cylinders get to the bottom, all the energy that we put in will have left. So how much power does the clock use? That is, how many Joules of egrney per second leave the clock if it takes 5 days for the cylinders to rtreun to their original position? We can figure this out because we already know how much work we did when we lifted the cylinders: 150 juloes. But this time, it took 5 days rather than a minute. Five days is 5 times 24 times 60 tmeis 60 again or 432,000 seconds. So we divide the work done by the time and find the answer of about 0.00035 Joules per second, or about 0.35 milliwatts. That's a tiny amount of power. This clock uses so little power that you could run almost 300,000 clocks using the same power it takes to run one 100-Watt light bulb. That's right, you could run a colck in every house in a medium sized city with that much power. That's a pretty aznimag conclusion and it took knowledge of work and power to figure it out.
Open Cloze
Joules per second, or Watts. The term Watt goes back to James Watt, who came up with the concept of horsepower to _______ the amount of power produced by a typical work horse. _____ Watt was a producer of _______________ engines, and he wanted his potential customers to be able to make comparisons between his steam _______ and a familiar quanity, the power they could get from a working horse. It was such a useful idea that the metric system unit for power, the Watt, is named after James Watt. Following in James Watt's footsteps, let's _______ the amount of _____ it takes to run this grandfather clock to the power we'd need to run a bright, 100-Watt light bulb. We can measure the power a person uses to wind the clock by dividing the amount of work they did by the time it took them to do it. If it takes 1 minute, or 60 seconds, to lift the weights, then they are doing 150 Joules _______ by 60 seconds, or 2.5 Joules per second of work. They are adding energy to the clock in the rate of 2.5 _____. You would need about 40 times as much to run a ______, 100-Watt light bulb. Before we let the clock run, the energy is ______ as ______________________ energy of the _________. It's like your bank _______ when you have just deposited money. But if we let the clock run, the cylinders slowly move downward. Energy is _______ the clock. In fact, when the cylinders get to the bottom, all the energy that we put in will have left. So how much power does the clock use? That is, how many Joules of ______ per second leave the clock if it takes 5 days for the cylinders to ______ to their original position? We can figure this out because we already know how much work we did when we lifted the cylinders: 150 ______. But this time, it took 5 days rather than a minute. Five days is 5 times 24 times 60 _____ 60 again or 432,000 seconds. So we divide the work done by the time and find the answer of about 0.00035 Joules per second, or about 0.35 milliwatts. That's a tiny amount of power. This clock uses so little power that you could run almost 300,000 clocks using the same power it takes to run one 100-Watt light bulb. That's right, you could run a _____ in every house in a medium sized city with that much power. That's a pretty _______ conclusion and it took knowledge of work and power to figure it out.
Solution
steam
joules
measure
cylinders
watts
engines
industrial
power
leaving
james
energy
gravitational
account
compare
divided
potential
stored
times
amazing
return
clock
bright
Original Text
Joules per second, or Watts. The term Watt goes back to James Watt, who came up with the concept of horsepower to measure the amount of power produced by a typical work horse. James Watt was a producer of industrial steam engines, and he wanted his potential customers to be able to make comparisons between his steam engines and a familiar quanity, the power they could get from a working horse. It was such a useful idea that the metric system unit for power, the Watt, is named after James Watt. Following in James Watt's footsteps, let's compare the amount of power it takes to run this grandfather clock to the power we'd need to run a bright, 100-Watt light bulb. We can measure the power a person uses to wind the clock by dividing the amount of work they did by the time it took them to do it. If it takes 1 minute, or 60 seconds, to lift the weights, then they are doing 150 Joules divided by 60 seconds, or 2.5 Joules per second of work. They are adding energy to the clock in the rate of 2.5 Watts. You would need about 40 times as much to run a bright, 100-Watt light bulb. Before we let the clock run, the energy is stored as gravitational potential energy of the cylinders. It's like your bank account when you have just deposited money. But if we let the clock run, the cylinders slowly move downward. Energy is leaving the clock. In fact, when the cylinders get to the bottom, all the energy that we put in will have left. So how much power does the clock use? That is, how many Joules of energy per second leave the clock if it takes 5 days for the cylinders to return to their original position? We can figure this out because we already know how much work we did when we lifted the cylinders: 150 Joules. But this time, it took 5 days rather than a minute. Five days is 5 times 24 times 60 times 60 again or 432,000 seconds. So we divide the work done by the time and find the answer of about 0.00035 Joules per second, or about 0.35 milliwatts. That's a tiny amount of power. This clock uses so little power that you could run almost 300,000 clocks using the same power it takes to run one 100-Watt light bulb. That's right, you could run a clock in every house in a medium sized city with that much power. That's a pretty amazing conclusion and it took knowledge of work and power to figure it out.