Ballast facts for kids

A ballast is a device or material used to add weight or control electric current. It helps keep things stable or working correctly.

There are different kinds of ballasts:

• One type is an electrical device that helps control the flow of electricity, especially in lights.
• Another type is a heavy material, often crushed stone, used to make things stable, like under railway tracks or inside boats.

Electrical Ballast

An electrical ballast is like a special resistor that controls how much electricity flows through a circuit. It's often used with fluorescent lamps (the long tube lights you see in schools or offices).

Why it's important: Without a ballast, the electric current in a fluorescent lamp could quickly become too high. This high current would make the lamp burn out very fast, like a light bulb blowing. The ballast makes sure the lamp gets just the right amount of electricity to glow brightly and last a long time.

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  Magnetic Ballasts: The top one is a Rapid start ballast, and the bottom two are preheat ballasts.

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  An electronic ballast that can power four lamps.

Railway Ballast

When you see train tracks, the crushed stones underneath them are also called ballast. This type of ballast is very important for keeping the railway tracks stable and safe.

Why it's important:

• It supports the heavy tracks and the trains that run on them.
• It helps drain water away from the tracks, preventing them from getting muddy or damaged by frost.
• It stops plants from growing around the tracks, which could cause problems.
• It holds the tracks in place, preventing them from shifting as trains pass over them.

Special machines called ballast tampers are used to pack these stones tightly around the tracks.

Ballast in Boats

In boats and ships, ballast is extra weight added to the bottom of the vessel. This weight helps to keep the boat stable and upright in the water, especially in rough seas.

Why it's important:

• It lowers the boat's center of gravity, making it less likely to tip over.
• It helps the boat stay balanced, even when waves are pushing it around.
• Some modern ships use special tanks called ballast tanks. These tanks can be filled with water (often seawater) or emptied to adjust the ship's stability and how deep it sits in the water.

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  A cross-section view of a boat showing a ballast tank at the bottom.

See also

In Spanish: Lastre para niños