James Prescott Joule was an English physicist and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). http://en.wikipedia.org/wiki/James_Prescott_Joule
James Watt was a Scottish inventor and mechanical engineer whose improvements to the Newcomen steam engine were fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world. http://www.bbc.co.uk/history/historic_figures/watt_james.shtml
A longcase clock, also tall-case clock, floor clock, or grandfather clock, is a tall, freestanding, weight-driven pendulum clock with the pendulum held inside the tower, or waist of the case. http://en.wikipedia.org/wiki/Grandfather_clock
Physics is a natural science that involves the study of matter and its motion through space and time, along with related concepts such as energy and force. http://www.scholarpedia.org/article/Encyclopedia_of_physics
Do you think that other devices could be powered by humans? For example, is it possible to make a car that works this way, where a human puts energy into it, the energy is stored, and then used to power the car? To answer this, research the amount of work or energy a human can produce and the amount of energy required for a car to drive.
What are some other possible devices that use the energy of our bodies for useful power?
Here are some starting points for your search:
http://sciencenewsdaily.org/energy-news/cluster247719330/
http://clarknet.eng.umd.edu/news/news_story.php?id=5726
http://en.wikipedia.org/wiki/Energy_harvesting
Compare the numbers in this TED-Ed lesson with the numbers in this video: http://www.youtube.com/watch?v=NojMfhiBX50 What observations do you make?