Who invented the electric light bulb in 1879?

Who invented the electric light bulb in 1879?

1879: Thomas Edison crowns 14 months of testing with an incandescent electric light bulb that lasts 13½ hours. Sir Humphry Davy had produced incandescent electric light in 1808 by passing battery current through a platinum wire. But the voltaic pile was expensive and could be messy.

Which is the hardest bone in the human body?

The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with the tibia and patella forming the knee joint. By most measures the femur is the strongest bone in the body. The femur is also the longest bone in the body.

How big is a communication satellite?

Modern communications satellites can weigh up to six tons and be the size of a small school bus. In order to give some idea of the size of modern communications satellites, here are some pictures of communications satellites as they are being built.

Why is Superman older than Supergirl?

Even though Supergirl (Kara Zor-El) was 12 when her parents sent her to Earth to escape Krypton to look after her baby cousin Superman (Kal-El), her pod was knocked off course and stuck in space and she was effectively stuck in time. By the time her pod reached planet earth, Kal-El had already grown up and become Superman while she was still young.

Who was the first Renaissance artist to use oil paints?

Most Renaissance sources, in particular Vasari, credited northern European painters of the 15th century, and Jan van Eyck in particular, with the “invention” of painting with oil media on a wood panel support (“support” is the technical term for the underlying backing of a painting).

Why are there balls on the power lines?

Power lines are thin and may be difficult to see by even low-flying aircraft, and we don’t want airplanes colliding with them. The big marker balls are there to warn airplanes of the power lines.

How many species of fish are in the great barrier reef?

More than 1,500 fish species live on the reef, including the clownfish, red bass, red-throat emperor, and several species of snapper and coral trout. About 5,000 species of mollusks live on the reef.

When was the segregation law abolished?

Although sometimes counted among “Jim Crow laws” of the South, such laws were also passed by other states. Anti-miscegenation laws were not repealed by the Civil Rights Act of 1964 but were declared unconstitutional by the 1967 Supreme Court ruling in Loving v. Virginia.