Clavichord was invented during the early 14th century (Baroque period). It was a very early form of the piano and is small rectangular wooden box. It produces a very stringy sound and has no dynamic control due to lack of pedals. (read more)

The first equal sign appeared in the Robert Recorde's book, The Whetstone of Witte in 1557. He wrote "And to avoid the tedious repetition of these words : is equal to... (read more)

Since any form of open flame can burn odor in the air, candles are good for eliminating odor like fish smell. They also create an attractive mood in the house. Open... (read more)

Around 300 B.C. Euclid of Alexandria proved that there are infinitely man prime numbers. He proved it by contradiction which is one of well-known proof methods. Suppose that prime numbers are finite and the largest prime number is p. The complete list... (read more)

1. Think of any 3 digit number as long as the first digit is 2 or more greater than the last one. 2. Reverse it. 3. Substract the smaller number from the bigger. 4. Reverse it. 5. Add numbers of the step 3 and 4. You will alwasy get 1089. Let's play... (read more)

Green tea does contain caffeine. The content of caffein depends on various factors such as length of brewing time. Green tea prepared from unfermented... (read more)

Studies have shown that tea may help prevent the development of type 1 diabetes and slow the progression once it has developed and also shown that... (read more)