December 2021

It is usually the knuckles, knees, ankles, back and joints of neck muscles that make the popping sound. It is caused by a small bubble that builds up in the fluid of the fingers. When these joints are pulled apart, a tiny cavity is formed which gets filled with gas. This gas bubble collapses and […]

We need sunscreen because it protects the skin from UV damage and sunburn. Sunscreens are over-the-counter products that come in lotions, gels, ointments and sprays. Our skin responds to excessive exposure to the sun by turning red, becoming hot, and becoming painful to the touch. Severe sunburns cause skin blistering and peeling. The sun’s rays

Photophobia, or sensitivity to light, is an intolerance to light. This is one reason why sunlight hurts our eyes. There is another reason too. We are able to see because light is able to travel through our eyeball to the retina. The retina is able to process only a certain amount of light that it

Flying fish have evolved this remarkable ability to glide over water with remarkable agility to escape their watery predators. They begin their ‘glide’ or ‘flight’ by gaining great velocity underwater. Using their tails, they gather momentum and shoot themselves or jump high out of the water. The flying fish beats its tail rapidly while still

Dolphins and whales are not fish at all! They are mammals like us and need to breathe oxygen through their noses, also known as ‘blowholes’ that are located on top of their heads. They are like other mammals on land, because whales and dolphins give birth to babies instead of laying eggs. They are warm-blooded

Fish need oxygen to breathe underwater too. They rely on their ‘gills’ to help them out in their breathing. Fish rely on oxygen present in the water surrounding them. That is why they need to have a system that helps them extract the small amounts of oxygen out of the water and into their bloodstream.

Dolphins have a unique quality of being able to create a large range of sounds that they use as their special communication system. They have a special body-part called the nasal air sacs that help them create these sounds. These sacs are located just behind their blowholes. They produce three different kinds of noises –

Going down the stairs burns just a third of the energy needed to climb up the stairs. It requires more energy. While, on the other hand, coming down requires lesser energy because you are working in the direction of the gravity. Gravitational pull of the earth helps you in that. Going up, you are working

This is called the ‘Mpemba effect’. It is due to the chemical bonds of water. When the water molecules are brought into close contact, a natural repulsion between the molecules causes the covalent bonds to stretch and store energy. When the liquid warms up, the hydrogen bonds stretch as the water gets less dense and

Ice-cream mixture is made up of three basic components at its molecular level – concentrated sweetened cream, ice crystals, fat globules and air. In its liquid form, ice-cream molecules have more energy and can vibrate more easily. But as soon as the liquid is cooled, energy is released, and the molecules move closer. Because of

Soda is a carbonated drink. Carbonated drinks are sealed under high pressure, low temperatures, with carbon dioxide dissolved in each can or bottle. Without this the drink would not have its fizz. As soon as you open the can or the bottle, the pressure inside the can decreases. It immediately converts the carbon dioxide to

Cotton, linen and hemp clothes usually gain wrinkles after washing. These wrinkles do not get erased with dry heating. Sprinkling the water softens down clothes. When heat is applied on it, clothes easily get smooth and it makes it easy to iron out the wrinkles. Also, when the wet clothes get ironed, steam is created

Microwaves generate very short, high frequency radio waves that are just right for being absorbed by water, fat and sugar molecules within organic matter. This energy causes them to vibrate at very high speeds, which in turn generates heat that cooks the food. However, the molecules of metal objects heat up quickly and with nowhere

Rainbows are a collection of rays that are reflected back from glinting raindrops that are suspended in the atmosphere after a rainstorm. The droplets act as tiny prisms that reflect the light at an angle of approximately 42 degrees. They have a different density than the air that surrounds them. So with each droplet acting

This is due to the Leidenfrost effect. In this, effect, when the wetness on the hands comes in contact with something hotter than the boiling point of the liquid (the hot object, in this case), it produces an insulating vapour layer preventing the water on the hands to become hot rapidly. A sort of film