Evaporation is the process by which water is converted from its liquid form to its vapour form and thus transferred from land and water masses to the atmosphere. In nature, the sun heats the water in ponds, lakes, rivers or sea, and changes into vapour and rises in air. Here water is also disappeared because of evaporation.

Water is not only colourless and odourless, it is tasteless too. 

Rainwater harvesting (also called roof water harvesting) involves the collection, storage and distribution of rainwater from the roof for use inside and outside the home or business. Rainwater that is captured and stored correctly is a safe, economical and sustainable source of quality water. By using rainwater harvesting systems to supply water for some, or indeed all of our requirements, you can reduce your dependence on mains water.

Temperature, size, distance from the earth and magnitude are indicators of brightness of sun.

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Condensation is the change of the physical state of matter from gaseous phase into liquid phase. The temperature of the ice cold water is close to zero. The air around the container consists of water vapour, which accounts to humidity. When the water vapour comes in contact with the outer surface of glass containing ice cold water, there is a change in physical state of water vapour to water in liquid phase due to lower temperature and condensation. Hence,  it accounts for the water droplets on the outer surface of a tumbler or a glass containing ice cold water.

The rings of saturn are the most extensive planetary ring system of any planet in the solar system. They consist of countless small particles ranging in size from micrometres to metres that orbit about saturn. In 1610, Galileo Galilei first turned a telescope to the sky, he became the very first person to observe Saturn's rings, though he could not see them well enough to discern their true nature.

A nerve cell also known as a neuron is an electrically excitable cell that processes and transmits information through electrical and chemical signals. Neurons connect to each other to form neural networks. Neurons are the core components of the nervous system, which includes the brain and spinal cord. It is the longest cell with a length of 90 cm -100 cm linking the central nervous system.

Venus is the second planet from the sun orbiting it every 224.7 earth days. After the moon, it is the brightest natural object in the night sky. The planet Venus is called the morning star because it can appear as the brightest, and the most visible celestial object (other than the Moon) in the morning.

Carbon dioxide gas is heavier than oxygen, so it creates a blanket around the burning fuel and displaces the oxygen surrounding the fuel. In a carbon dioxide extinguisher, the carbon dioxide is kept in pressurised liquid form in the cylinder. When the container is opened, the carbon dioxide expands to form a gas in the atmosphere or to simplify, it removes oxygen from the fire triangle, to smother it and extinguish it.

The polar bear (Ursus maritimus) is a bear native to the Arctic Ocean and its surrounding seas. It is the world's largest carnivore found on land, and shares the title of the largest land predator. An adult male weighs around 400–680 kg while an adult female is about half that size.

We drink water to remain healthy and intake for men is roughly 3 litres (about 13 cups) of total beverages a day. So this is the activity in which least amount of water is used.

Oviparous animals are animals that lay eggs, with little or no other development within the mother. Examples are crocodiles, alligators, snakes, salamanders, lizards, turtles, etc.

At - 8 degree Celsius temperature, the water in Dal lake goes below the freezing point as the freezing point is 0 degree Celsius. So, the water in Dal lake will freeze and the lake will become so hard so that any body can walk and play on that.

Matter in the gaseous state has both variable volume and shape adapting both to fit its container. Its particles are neither close together nor fixed in place. For example, oxygen, carbon dioxide, steam, etc.