What causes a reflex? A reflex is an automatic or involuntary response by the body to an external stimulus. Reflexes are caused when nerve impulses bypass the brain. Instead they are transferred by the spinal cord to motor cells which send currents to the muscles...
Why is Venus called the Evening Star? Among the planets, it is Venus whose orbit comes closest to earth. After sunset, Venus is visible, shining in the western sky. This is why it is called the evening star. In size, Venus is almost the same...
Who was Cyrus the Great? Cyrus the Great was a great Persian king. Around 3,000 centuries ago, Persia or current-day Iran was ruled by the Medes and the Persians. It was in 550 BC that Cyrus seized power. It was he who turned Persia into...
Which dinosaurs used claws to kill their prey? A dinosaur named Deinonychus meaning ‘terrible claw’ and its kin had claws to kill their prey which would comprise even larger animals. They would leap at their prey and slash them with their claw. The claw was...
Why is the mocking bird called so? The mocking bird is very good at imitating the songs and cries of other birds. It even improves on a bird’s song by adding its own runs and trills. The bird also imitates other sounds like a dog’s...
Why do plants turn toward the sunlight? Plants use chlorophyll to make their food and it is found in leaves. Chlorophyll needs sunlight to produce food or sugar. Plant cells have something called auxins which collect in the cells on the side of the stem...
Why is the White House called so? The White House didn’t always have this name. But it has always been the official residence of the American president. Initially it was called the President’s house or mansion or palace. It was built of grey sandstone at...
Where was the first theatre? Theaters developed in Greece first as part of religious worship. The stage was a circle of turf on which worshippers danced around the altar of Dionysus. There were theatres in Greece as early as 500 BC. The first permanent stone...
What causes lightning? A Cloud has droplets of water which have a positive electrical charge at the top of the cloud and a negative charge at the bottom. Sometimes the negative charge comes near an attracting positive charge on the earth or another cloud. This...
Did the Persians and Greeks wage war? The Persians and Greeks fought each other for several years. In 480 BC, the Battle of Salamis occurred. In this war, the Persian fleet had to retreat before the might of the Greek triremes. Triremes were ships powered...
