Welcome
The page contains information about a mechanical clock. We are trying to learn more about how students read and learn from a webpage in combination with a hands-on puzzle: putting together a mechanical clock.
Information about each part of the clock is presented in the sections below. These sections contains explanations, drawings, animations, and videos. You can also jump to each section using the menu at the top of the page.
If you get stuck, Richard (the researcher) is there to help you. Make sure to let him know if you get stuck so he can help!
Information about each part of the clock is presented in the sections below. These sections contains explanations, drawings, animations, and videos. You can also jump to each section using the menu at the top of the page.
If you get stuck, Richard (the researcher) is there to help you. Make sure to let him know if you get stuck so he can help!
The Big Picture: How a Mechanical Clock Works
All modern clocks work in the same basic way, and can be divided into analogous parts. They all have an object that repeats the same motion over and over again, called the oscillator, which has a constant time interval between each repetition, or beat. Attached to the oscillator is a controller device which has two jobs. First, it keeps the oscillator going by replacing the energy it loses to friction. Second, the controller device converts the oscillations into a series of pulses. A counter is used to convert the pulses into seconds, minutes, and hours. Finally, an indicator displays the time in a human-readable form.
One type of mechanical clock uses a pendulum, which is a weight (or bob) that hangs from the end of a stiff rod. As a pendulum swings, the time that it takes the bob to swing out from its starting point and come back again is always the same. The regular movement of the pendulum allows the clock to keep time accurately. Until the invention of the pendulum clock, mechanical clocks were unable to keep track of time reliably. The following video explains how a mechanical clock works. This is only meant to be an overview, so you're not expected to understand everything. This website provides the detail that is missing from the video. |
The Weight
A pendulum clock is powered by a hanging weight. The weight hangs from a string that is wrapped around a spool. This spool is mounted on an axle that is connected to one or more gears. As the weight falls, the axle and the connected gears turn. (See the animation on the left.)
These gears transmit energy from the weight to the rest of the clock. The energy from the falling weight turns the gears, which turn the escape wheel. The escape wheel pushes on the anchor to keep the pendulum rocking back and forth. As the pendulum rocks, it causes the gears to rotate at a fixed rate in time with the pendulum. |
The Anchor and Escape Wheel
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The Pendulum
The Hands
The hands on a clock point to numbers that indicate the time. Each of the hands rotates at a different speed. For example, the second hand makes one full rotation every 60 seconds.
The hands on the clock are connected to axles that are turned by gears. There are a number of gears inside the clock. These gears work together to convert the energy from the falling weight into rotational motion that (a) turns the hands and (b) turns the escape wheel. Along the way, the gears also speed up / slow down this motion so the hands move at the correct speed. |