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You will learn about "Dalton's Atomic Theory" in this video. John Dalton was an English chemist who is very well known today for his work in the development of atomic theory. Let us learn the postulates of Dalton's atomic theory. All matter, whether an element, a compound or a mixture are made up of very tiny particles called atoms. All atoms of a given element are identical in size, mass and chemical properties. Atoms of different elements differ in size, mass and chemical properties. Atoms are indivisible particles which can neither be created nor destroyed in a chemical reaction. Atoms combine together in fixed whole number ratios to form compounds. In a chemical reaction, atoms only get rearranged. An atom of an element does not change into the atom of another element.

hat is color blindness? A color festival. No. Color blindness or color deficiency is a vision problem. Now, our eyes have light sensitive cells called rods and cones. Can I put ice cream on these cones? You are just unbelievable. Rods are responsible for black and white vision. They do not detect color. Whereas, cones detect color. There are three types of cones. One cone perceives red light, another perceives green and the third perceives blue. Together, these cones help us to see the whole spectrum of colors. Now in some cases, when one or more types of cones do not work properly, it causes color blindness. People with such deficiency have difficulty in distinguishing between certain colors or shades. For example, in red-green color blindness, the apple tree may appear like this.

Topic: Turgor Pressure Why does a touch me not plant close? Hey!! Don't touch that plant. You will get scared. See, you did not listen to me. Don't worry!! Nothing to be scared about. Let me tell you more about this plant. This plant is called the Mimosa Pudica plant. Another name for it is "Touch Me Not" Plant. When anyone touches this plant, it closes its leaves with the help of pulvini. Pulvini are present at the base of each leaflet. They consist of cells filled with water. This water applies pressure against the walls of the cells. This pressure is called the turgor pressure. It helps the leaflets to stand upright. Now, when we touch a leaflet of the touch me not plant, specific parts of the plant release certain chemicals. These chemicals cause the cells in the pulvini to lose water. When water is lost, there is no more turgor pressure. As a result, the cells collapse, resulting in the closing of leaflets.

Topic: Diffusion Why can we smell hot food from a distance?

Topic: Surface Tension Why are drops spherical? Naahhh!!! It is because of surface tension. Surface tension is the property of liquids by which surface molecules of a liquid try to hold the liquid together by acquiring minimum surface area and acting like a stretched membrane. Alright!! I'll explain!! Inside a drop, each water molecule is pulled with a force by its neighboring molecules. As these forces are equal and opposite, they get neutralized. However, the molecule present at the surface is not attracted outwards. It is attracted only inwards and sideways. Sideways forces get neutralized. But because of the inward force, each surface molecule contracts to form a shape that has minimum surface area which is a sphere.