Sahil Gupta

The Dead Sea is a lake. It is 50 kilometres long and 15 kilometres wide. The Jordan river and some small canals drain into it. But no river originates from the Dead Sea. As a result, the water depletes only by evaporation, leaving the salt behind. Moreover, due to its location, it does not receive […]

Oil lubricates things. A lubricant is a film of liquid that prevents parts from touching, so they slide easily past one another. Lubricants generally work because their molecules bind more tightly to the parts that would otherwise rub together than they do to one another. The oil added to machines sticks to the metal parts,

It is because of the molecules that are present in the food. If we rub our hands in egg-yolk, it will not stain our hands. This is because the egg yolk molecules are very large and do not stick to our hands. However, things like grass, wet paint or food colouring will leave a stain

This is because the Dead Sea is nearly six times as salty as the ocean. It also contains many other dissolved minerals, including magnesium chloride, calcium chloride and potassium chloride in large quantities, in comparison to fresh water in which there are found only minute quantities of these minerals. The high concentration of salt makes

Salt comes from rocks on land. Rainfall contains some dissolved carbon dioxide from the surrounding air. This causes it to be slightly acidic. As the rain erodes the rock, acids in the rainwater break down the rock. This process creates electrically charged atomic particles. These ions are carried through streams and rivers to the ocean.

The colour of milk is white due to the protein and fat molecules reflecting back light wavelengths; butter is yellow in colour due to the higher fat-content. The yellow pigment, called ‘beta carotene’, is found naturally in plants, which are eaten by cows. The pigment is carried over in the milk as fat. The fat

Water is clear because nothing in it reflects light. We see different things because light from them gets into our eyes. If something has nothing in it to bend or bounce light, we don’t see it. If the water has a dye in it and that absorbs some colour of light, then we will see

It was Newton’s observation that objects do not have their colours. The surfaces of the objects reflect some colours while absorbing others. We see only the reflected colours and that is how we are able to distinguish colours. For example, the apple will reflect the colour red while absorbing the rest. We see the red

Plants make molecules that have aromas for several reasons. From the unsavoury stink of the skunk cabbage to the pleasant smell of the sweet peas, almost all plants discharge a certain amount of pleasant or stench-like smells. However, these smells are not for the benefit of the human nose. Some of these smells, created by

Skunks use their odour to defend themselves and keep predators away. They spray a mixture of chemicals from a special gland when they feel threatened. They are notorious for their pungent and nauseating odour, basically like the smell rotten eggs have. As soon as the skunk feels that it is being attacked, it will turn

Our noses are able to discern between a pleasant smell and a stinky smell, because of the spread out of molecules of those substances/smell. Heavier, more spread-out molecules smell stinkier than compact molecules. However, there are always exceptions to the rule but in general, a substance that has spread out molecules with light electron density,

Sounds that we hear are the result of air molecules being pushed against our eardrums. When an explosive is set off, a large number of gas molecules are produced that are pushed together with air molecules to create sound waves. The faster the air is pushed, the more pressure is created, since the air has

Besides preventing people from misusing certain drugs, liquid drug delivery systems are sometimes preferred because they are faster acting than pills. Pills make bad-tasting medicines easy to swallow because only a little of the medicine actually touches the tongue before the pill is swallowed. Liquid medicines can be absorbed more rapidly than most pills. While

Our skin has a natural protective layer of oil that keeps it from drying out. If bacteria get accumulated over the skin and over the layer of natural oil, washing with soap will remove both the oil and the bacteria. Washing hands helps remove germs that can lead to diarrhoea-related sickness and respiratory infections. Furthermore,

Goggles are worn for safety purposes. Unlike food, like salt and pepper, if chemicals like acids, alkalis or abrasive powders, get into our eyes, we can neither wash them away with water nor will they get cleaned out of our eyes through tears. When we do experiments with chemicals, or when we heat something up,