11 February: Light bulbs

On this date in 1954 a 75,000 watt Light bulb was lit at the Rockefeller Center in New York, to commemorate the 75th anniversary of Edison’s first light bulb. 10 things you might not know about light bulbs:

1. Thomas Edison is generally credited with inventing the light bulb, but he was only one of many who worked on ways to produce light using electricity, including Alessandro Volta, Humphrey Davy, Warren de la Rue, William Staite and finally Joseph Swan who came up with something very similar to a light bulb as we know it in 1860. Swan’s invention had an issue with its filament, and Thomas Edison stepped in to correct that, and patented the result.

2. The brightness of a light bulb is measured in lumens.

3. The filament inside a light bulb is made from tungsten. The filament erodes over time and will eventually break. Then the bulb no longer produces light and must be replaced.

4. Traditional incandescent light bulbs typically last around 1,000 to 2,000 hours, depending on usage.

5. There is a light bulb at the Livermore/Pleasanton Fire Department in California which has been in use since 1901. It has been burning for over 120 years and is hardly ever turned off. In 2001, the bulb's 100th birthday was celebrated with a community Barbecue and live music. The Livermore-Pleasanton Fire Department plans to house and maintain the bulb until it finally goes out. They have no plans for it after that, although Ripley's Believe It Or Not has requested it for their museum.

6. Incandescent light bulbs lose up to 90% of their energy through heat.

7. There are about 600 million light bulbs currently in operation in the UK, that's an average of 25 light bulbs per household. This means that for every person in the UK population, there are just under 9 light bulbs.

8. There are even light bulbs in space. Light bulbs have been used on Space Shuttles and the International Space Station for specific applications.

9. Although it’s not usually detectable by the human eye, light bulbs tend to flicker. Studies have shown that this flickering can have an effect on focus and concentration.

10. Fluorescent bulbs contain gas and a little bit of Mercury, which means they must be disposed of carefully.