1. Can you guess how the Bats can locate their prey even in the dark?
Actually bats emit ultrasonic squeaks while flying and listen to the echoes produced by the reflection of their squeaks from the prey like a flying insect. From the time taken by the echo to be heard, bats can judge the distance of the insect and hence catch it. Hence, fever is not a disease, but an indication.
2. How do the rockets move upward?
You must have seen the burning gases exhausting out of the hind nozzle of the rocket which are produced due to the combustion of the fuel. As these burning gases escape out with the very high velocities, in accordance with the Newton’s third law of action and reaction, they impart an equal and opposite reaction to the rocket thus making the rocket to move in the forward direction with a great speed.
3. We often see the students carrying heavy school bags having the broad strips.
Do you know the reason why these carrying bags are mostly provided with the wide strips? The answer comes from the relation between force, pressure and area i.e. Pressure= Force/Area. Actually the wide strips make the weight of the bag fall over a large surface area of the shoulder and thus producing less pressure on the student’s shoulder making it easier to carry the heavy school bag.
4. Do you know why you feel itching on the healing wounds ?
Actually there are certain itch-specific nerve fibers in the skin. Their sole job is to send signal to the spinal cord that an area of skin is being stimulated, which is perceived by the brain as itchy. In the healing stage, a wound heals and closes by laying down cells that flow downward towards the base of the wound. Herce they unite with other cells that will create the framework to help close the wound. As those cells contract and pull the wound closed, the mechanical pull on the skin stimulates the sensation of itchiness.
For more similar science facts, follow Josh CBSE on Facebook at www.facebook.com/jagranjoshcbse