BRAIN TEASERS
Brain Teasers User Profile

Cristian Untaru

rank
790
points
0
See full ranking list
short ranking list
788. F1ak Games 0
789. knaf 0
790. Cristian Untaru 0
791. Robin George 0
792. Claudemir CCB 0
last 3 solved tasks

Armand-Hippolyte-Louis Fizeau

Died 18 Sep 1896 at age 76 (born 23 Sep 1819). French physicist who was the first to measure the speed of light successfully without using astronomical calculations (1849). Fizeau sent a narrow beam of light between gear teeth on the edge of a rotating wheel. The beam then traveled to a mirror 8 km/5 mi away and returned to the wheel where, if the spin were fast enough, a tooth would block the light. Knowing this time from the rotational speed of the wheel, and the mirror's distance, Fizeau directly measured the speed of light. He also found that light travels faster in air than in water, which confirmed the wave theory of light, and that the motion of a star affects the position of the lines in its spectrum. With Jean Foucault, he proved the wave nature of the Sun's heat rays by showing their interference (1847).

Name the animals...

The first-grade teacher was showing pictures of animals to her students to see how many they could name. She held up a picture of a lamb, and a little girl said, "That's a sheep!"

"That's right!" said the teacher. "How about THIS one?" she said, holding up a picture of the king of beasts.

"That's a lion!" answered a little boy.

"Right!" said the teacher. Then she held up a picture of a deer. No one volunteered an answer. She tried to help. "What does your mother call your father?"

Johnny said, "I know! That's a lazy old goat!"

Jokes of the day - Daily updated jokes. New jokes every day.
Follow Brain Teasers on social networks
This site uses cookies to store information on your computer. Some are essential to help the site properly. Others give us insight into how the site is used and help us to optimize the user experience. See our privacy policy.