In

the

1300s,

a

mechanical

clock

was

invented.

This

type

of

clock

contains

a

weight

that

is

pulled

down

by

gravity

and

spins

gears

that

move

the

clock’s

hands.

In

the

1400s,

springs

replaced

the

weights.

In

1656,

a

Dutch

scientist

named

Christian

Huygens

built

a

pendulum

clock.

A

pendulum

swings

in

a

steady

motion,

which

keeps

the

hands

turning

at

an

even

rate.

A

pendulum

clock

A

mechanical

clock

Gear

Hour

hand

Weight

Minute

hand