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Lighthouse

technology Maturity 9-11 Next article →

A lighthouse is a tall structure built to shine light. This light acts as a beacon for ships at sea. It helps sailors navigate through dark or foggy waters. Lighthouses mark dangerous places like rocky reefs or shallow shoals. They also show safe paths into busy harbors. Some lighthouses even help pilots flying in the air. Today, many use electronic tools to guide ships. However, these towers remain important symbols of safety on the water.

Kapu Beach Lighthouse
Kapu Beach Lighthouse

How does a lighthouse work so well? It uses a system of lamps and special lenses. The light starts at a lamp, which might use oil or electricity. Then, the light passes through a lens to make it stronger. A famous design is the Fresnel lens, named after Augustin-Jean Fresnel. This lens is thin but can capture a lot of light. It focuses the light into a single, powerful beam. This beam can be seen from very far away. Some lighthouses even use rotating lights to create flashes.

Fresnel lighthouse lens diagram
Fresnel lighthouse lens diagram

Lighthouses have a very long history. Long ago, sailors watched for fires on top of hills. Later, people built platforms to lift these fires higher. The most famous ancient lighthouse was the Pharos of Alexandria in Egypt. It stood for a long time before earthquakes caused it to collapse. In Spain, the Tower of Hercules is still standing today. This ancient tower gives us clues about how people built lighthouses long ago.

Torre de Hércules 2023
Torre de Hércules 2023

Many clever engineers have improved lighthouse design. John Smeaton rebuilt the Eddystone Lighthouse between 1756 and 1759. He used granite blocks and a special type of concrete. He even shaped the tower like an oak tree to help it stand. Another builder, Robert Stevenson, worked for the Northern Lighthouse Board for fifty years. He helped create rotating lights that changed between red and white. In 1838, Alexander Mitchell began building screw-pile lighthouses. These used piles that were screwed directly into the sandy seabed.

Smeaton's Lighthouse00
Smeaton's Lighthouse00

Lighthouses are connected to the technology we use every day. In the past, keepers used whale oil or coal to make light. Now, many lighthouses are automatic and use solar power. They charge batteries during the day to keep the light bright at night. Some use a diesel generator if they need extra power. We also use the Global Positioning System, or GPS, to find our way today. Even with new tools, the steady glow of a lighthouse is a wonderful sight.

Point Danger lighthouse
Point Danger lighthouse
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🖼️ Images & Media (15)
File:NJ LBI Lighthouse 04.JPG
NJ LBI Lighthouse 04.JPG
Roman Rock Lighthouse.webm
File:Torre de Hércules 2023.jpg
Torre de Hércules 2023.jpg
File:Edystone Winstanley lighthouse Smeaton 1813.jpg
Edystone Winstanley lighthouse Smeaton 1813.jpg
File:Smeaton's Lighthouse00.jpg
Smeaton's Lighthouse00.jpg
File:Marjaniemen majakka.jpg
Marjaniemen majakka.jpg
File:Sumburgh Lighthouse Lamp.jpg
Sumburgh Lighthouse Lamp.jpg
File:Fresnel lighthouse lens diagram.png
Fresnel lighthouse lens diagram.png
File:Point Danger lighthouse.jpg
Point Danger lighthouse.jpg
File:Cape Meares Lighthouse lens - Oregon.jpg
Cape Meares Lighthouse lens - Oregon.jpg
File:Lighthouse lantern room with Fresnel lens.png
Lighthouse lantern room with Fresnel lens.png
File:Margaree Harbour Range Lights.jpg
Margaree Harbour Range Lights.jpg

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