To answer this we need to know what happens when a liquid boils.  At the boiling stage of any liquid, the vapor pressur…

https://www.pxfuel.com/ If you look at the colour red for a long time and then look around you see things in greenish t…

The Babylonians (who lived in about 1000 BC) used base 60 arithmetic. Hence their fractions were written in a sexagesim…

All the planets in the solar system spin on their axes (so does the Sun!) and so they have day and night cycles. There…

https://www.pxfuel.com/ When you cut an apple you're actually bursting open the tiny, little cells that make up the…

Our bodies are covered with hair, each of which has a gland at the bottom which pumps out an oily substance called se…

Wikimedia Commons Salt is a water-loving chemical. Salt in you mouth or stomach sucks water from your blood stream whic…

https://pixnio.com/ Ice is a crystalline material, meaning that the water molecules in it are regularly ordered. The su…

Tear gases are irritants –– they irritate mucous membranes in the eyes, nose, mouth and lungs, and cause watering of ey…

Pure colors require pure ingredients. Even trace amounts of sodium impurities (yellow-orange) are sufficient to overpow…

A basic cell phone is a two-way radio, consisting of a radio transmitter and a radio receiver. When you chat with your…

X-rays were discovered in 1895 by Wilhelm Conrad Röntgen, who received the first Nobel Prize in Physics in 1901. Severa…

A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of …

When a boat is placed in water, it displaces an amount of water equal to its volume. In other words, it takes the place…

We measure the temperature of far-away objects by investigating the radiation (mostly light) they emit, and we can do t…

This is because you have to apply a very small force to open or close the door. This is due to the couple acting on the…

Chlorine is used as a disinfectant to kill bacteria, algae, germs in the swimming pool water so that it is safe for swi…

Bacteria have a cell membrane and a cell wall. Bacteria must live in an aqueous (watery) environment. Most often this i…

The most striking feature of an owl is its eyes. Large and forward-facing, sometimes they are approximately five percen…

Yawning is a normal stretching mechanism. It's similar to stretching other muscles in the body. Normally we stretch…

In the Olympics, a high jumper cleared a height of about 2 Meters. If the same person were to compete in the Olympics h…

The Sun’s energy comes from nuclear reactions that is the conversion of hydrogen to helium by the fusion reaction.  Th…

The attractive force of surface tension causes the bubbles to take spherical shape. Because a sphere has the smallest s…

All planets are round because of gravity. When our solar system was forming, gravity gathered billions of pieces of gas…

When lightning strikes, current or discharge flows through the lightning channel. It heats the channel to very high tem…

Display of colors by a CD can be understood in terms of the working of a plane optical reflection grating. The data whi…

A chemical called Capsaicin is responsible for the hotness of chillies. Chilli plants pump their fruits full of capsai…

An important component of tears is lysozyme, a chemical that inhibits bacterial growth on the eye's surface. Some o…

When you chop an onion, you break open some of the onion's cells. This releases enzymes which take part in complex …

Chewing gum used to be made from thickened resin and latex from certain kinds of trees, or from various kinds of sweet …