PENDULUMPENDULUM

What’s a pendulum anyWhat’s a pendulum anyway??way??

What is a pendulum scientificallWhat is a pendulum scientifically important??y important??

WRONG IDEASWRONG IDEASThe earth is flat.The earth is flat.

The sun, moon, stars rotate the The sun, moon, stars rotate the earth each day. earth each day.

In the 6th century B.C. In the 6th century B.C. －－ ARISTARCHUSARISTARCHUS 1543, COPERNICUS1543, COPERNICUS

NEWTONNEWTON

In 1851, a French physicist In 1851, a French physicist named named FOUCAULTFOUCAULT found a found a

way to prove the earth way to prove the earth rotates via a OENDULUMrotates via a OENDULUM

FOUCAULT’s first demonstrationFOUCAULT’s first demonstration

FOUCAULT’s second demonstrationFOUCAULT’s second demonstration

FOUCAULT’s third demonstrationFOUCAULT’s third demonstration

1852, Foucault also invented th1852, Foucault also invented the "GYROSCOPE," e "GYROSCOPE,"

How the FOUCAULT PENDULUM works.How the FOUCAULT PENDULUM works.

TODAYTODAY -- you can see this -- you can see this FOUFOUCAULT PENDULUMCAULT PENDULUM demonstra demonstra

tion yourself at thetion yourself at theCALIFORNIA ACADEMY OF SCALIFORNIA ACADEMY OF S

CIENCESCIENCES..

Why does the pendulum Why does the pendulum demonstrate the rotation of the demonstrate the rotation of the

earth??earth??

Let's consider -- Let's consider -- what ARE the what ARE the forces acting on forces acting on the pendulum?the pendulum?

We must understand the We must understand the differencdifferencee between 2 kinds of motions between 2 kinds of motions

Traveling Twisting

If the Pendulum was at the EQUATOR If the Pendulum was at the

POLE

Degrees of TWIST per day may be Degrees of TWIST per day may be determined determined mathematicallymathematically by this by this

formula formula

and can be demonstrated by using the pendulum                        

Latitude = angular distance of a place from the equator

EXAMPLE EXAMPLE

by a Foucault Pendulum, man can demonstrate at any point on the Earth's surface (except on the equator) that the earth rotates--

How Rotation of the Earth affectsHow Rotation of the Earth affectsour Live??our Live??

How to figure the period of a simple How to figure the period of a simple pendulum??pendulum??