Chain Facts for Kids

A chain is a series of connected links, usually made of metal. Chains can have two or more links joined together.

Some chains are made for lifting heavy things, like with a hoist, or for pulling. They can also be used for securing items, like a bicycle lock. These chains have links shaped like a donut (called a torus). This shape lets the chain bend in two directions, making it very flexible.

Other chains are designed to transfer power in machines. Their links are shaped to fit perfectly with the teeth of sprockets (geared wheels). These chains usually bend in only one direction. They are often called roller chains, but there are other types too, like block chains.

You can connect two different chains using a quick link. It looks a bit like a carabiner, but it has a screw to close it instead of a latch.

What Are Chains Used For?
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What Are Chains Used For?

Part of The Hudson River Chain at West Point, used to block ships during the American Revolutionary War.

Chains have many different uses, from fashion to powerful machinery.

Chains for Decoration

Chains are often used to make things look nice:

Chain of office: A special collar or heavy gold chain worn by important people in medieval Europe and the United Kingdom. It showed their position or loyalty.
Clothing decoration: Some people wear wallets with chains connected to their belts. Others have pants decorated with chains for a cool look.
Jewelry: Many necklaces and bracelets are made from small chains of gold and silver. There are different styles like the Figaro chain or the Omega chain.

Chains for Power Transfer

Chains are very important for moving power in machines:

Bicycle chain: This chain moves power from the pedals to the back wheel of a bicycle, making it go.
Chain drive: This is a system that uses a chain to transfer power. It was a key feature that made the "safety bicycle" (the kind we ride today) popular.
Chain gun: This is a type of machine gun that uses an outside power source, sometimes connected by a chain, to make it work.
Chainsaw: A portable saw that uses a special cutting chain to cut wood.
Roller chain: This is the most common type of chain used to transfer power in bicycles, motorcycles, and many industrial machines.
Timing chain: Found in car engines, this chain makes sure different parts of the engine move together at the right time.

Chains for Security and Restraint

Chains are also used to keep things safe or to hold them in place:

Bicycle lock: A chain that can be locked to keep your bike safe from theft.
Chain boom: Large chains used in history to block warships from entering harbors or rivers.
Chain link fencing: A common type of fence made from wires bent in a zig-zag pattern and linked together.
Chain mail: A type of armor from the past made of many small metal rings linked together. It protected knights in battle.
Door chain: A security chain on a door that lets you open the door a little bit from the inside while still making it hard for someone outside to force their way in.
Security chain: A strong chain often with square edges, designed to be hard to cut with tools like bolt-cutters.

Chains for Traction and Pulling

Chains help things move or pull heavy loads:

Anchor cable: Used by ships and boats to hold them in place. In British sailing, it's called a cable, not a chain, even if it's made of links.
Curb chain: Used on a horse's bridle to help control the horse.
High-tensile chain: A very strong chain used for towing vehicles or securing heavy loads on trucks.
Snow chains: Placed around car tires to improve grip and traction when driving in snow or ice.
Pull switch: An electrical switch that you operate by pulling a chain, often found on ceiling lights.

Chains as Weapons

Chains have been used in different ways as weapons:

Chain gun: As mentioned before, a type of machine gun that uses an external power source.
Chain shot: A special type of cannonball used in naval battles. It was designed to damage the sails and ropes of enemy ships.
Chain weapon: A medieval weapon made of one or more heavy parts attached to a handle with a chain, like a flail.

Other Uses for Chains

Chains have even more interesting uses:

Music: Chains can be used as a percussion instrument to create special sound effects in music.
Keychain: A small chain that connects small items, like charms or fobs, to a keyring.
Chain stitch: A sewing and embroidery technique where stitches form a chain-like pattern.