Science & Mathematics Questions & Answers

The touch-me-not shrinks due to loss of turgidity (the pressure of content against the cell wall) by cells within the pulvini-specialised motor organs at leaf joints. Upon stimulation, like touching, the leaf cells lose potassium ions, triggering water to leave the cells through osmosis. It takes about 10 minutes for the cells to regain turgidity and the leaves to open …

Some sunlight is essential for the formation of our bones as children, and to help us stay healthy and resist infection. However, if we stay in the Sun too long, some of its rays can cause the skin to go red and burn. It is better to avoid being in the Sun at mid-day, which is when the Sun’s rays …

Have you ever noticed that when you are in a car, or a bus, travelling on a straight road, the Sun appears to move right along with you? While telephone poles and trees close to the road, whiz past in the blink of an eye, the Sun is always visible throughout the journey. No matter how fast Daddy drives, you …

A phenomenon called Rayleigh’s Scattering causes light to scatter when it passes through particles that have a diameter one-tenth that of the wavelength (colour) of light. Sunlight is made up of different colours, but because of the elements in the atmosphere, the colour blue is scattered more efficiently than other colours making the sky appear blue. However, the moon does …

The moon orbits near the equator of the Earth. In the southern hemisphere, we are standing at the opposite side of the globe, from a person who is standing in the northern hemisphere. So, we are literally standing upside down with relation to the person at the other end. We, therefore, see the moon from a completely different vantage point. …

Like all other flowering plants, jasmine also produces a flower inducing hormone in its leaves when exposed to bright sunlight. This hormone is called florigen (flower-generating hormone) and it migrates from the leaves to flowering shoots during the day. It accumulates in the flowering shoots of the jasmine plant and induces flowering during the night.

Each aircraft is fitted with two pieces of equipment – Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) – that are designed to survive an air crash so that the data recorded helps investigators reconstruct events preceding the crash. FDR records values of about 700 parameters related to the flight and controls and CVR records conversations taking place in …

Hot steel glows red when hot because its atoms vibrate with a lot of energy. The amount of energy varies in atoms resulting in a range of colours.

Snow is a block of individual ice crystals arranged together. When a light photon enters a layer of snow, it goes through an ice crystal on the top, which changes its direction slightly and sends it on to a new ice crystal, which does the same thing. Basically, all the crystals bounce the light all around, so that it comes …

On a sunny day the bright sunlight bounces off the white snow, making the light even brighter. It usually takes a while for our eyes to become comfortable when we look at something as bright as that. People often wear sunglasses when they go skiing or go to the beach to protect their eyes from the strong light.