Planets
We have studied about the planets of our solar system in previous classes. We will study only these four planets here.
Mercury
It is named after the name of the messenger of the Roman gods. Mercury takes 58 days to spin on its axis and 88 days to revolve around the Sun. There is no atmosphere and water on this planet. It is covered in craters. The biggest craters on this planet is calories basin.
Venus
It is named after the Roman goddess of love and beauty. It is the most beautiful object in the sky. This planet was first observed by Galileo. Venus is the more...
Other Heavenly Bodies
Asteroid
Large number of small bodies that fills the gap between the orbits of the Mars and Jupiter and revolve around the Sun like other planets. Asteroids are called as minor planets because it has its own orbit and its size varies from kilometer to few hundred kilometers. About 3500 asteroids are orbiting the Sun.
Comets
They are very small sized celestial bodies made up of balls of ice and rock and revolve around the Sun. They become visible to us only when come closer to the Earth. They usually have a small head and a glowing tail of gas. The size of the more...
Reproduction
Reproduction is the process of producing offspring of its own kind. For example an apple tree can produce another apple tree only, it can't produce mango tree.
Vegetative reproduction is a type of asexual reproduction in which new plant is generated from the vegetative part of the plants i.e. stems, roots, leaves etc.
Vegetative reproduction by Stem
Runnerss
Reproduction in strawberry
Stems, which run horizontally parallel to the ground. New roots emerge from the nodes, thus gives rise to new plants e.g. lawn grass, strawberries etc.
Suckers
Vegetative reproduction more...
Rock Cycle
The rock cycle involves the formation, alteration by weathering and then formation of rock again. All the process occurs simultaneously.
Weathering of Rocks
Weathering of rocks takes long time. After weathering, rocks are converted into soil.
1. Strong desert winds 2. Flowing water
3. Ocean tides 4. Glaciers
more...
Rocks and Minerals
Lithosphere Lithosphere of the earth mainly consists of rocks and soil. Rocks and soil both are natural resources. Rocks are made up of grains called minerals. One or more than one minerals are present in one kind of rock. Minerals can be seen or can't be seen with the naked eyes. Minerals are very important natural resource as they contain ores, from which metals and non-metals can be obtained profitably.
Types of Rocks
| Examples | more...
 Soil Erosion
Removal of the top fertile layer of the soil due to weathering is called soil erosion. Heavy rain fall and wind are the cause of soil erosion.
 Soil Erosion by Wind
Particles from the top layer of the soil are lifted up by the Wind to carry it to some other place. This type of erosion of soil generally occurs in arid regions with little vegetation or no vegetation.
Soil Erosion by Rain and Running Water
Due to cutting down of trees and less vegetation, the top fertile layer of the soil is exposed and hence it can be easily carried away with flowing water and rain water. more...
 Soil
Soil is the uppermost layer of the earth's surface which is made up of the particles of rocks, humus, air and water. Soil contains nutrients and water for the survival of plants. The product, after the process of photosynthesis is glucose, which is made by the plant in the presence of carbon dioxide and Sun rays. The leaves of the plant trap Sun rays and carbon dioxide from the atmosphere. The other necessary nutrients such as, water and minerals are absorbed by the root from the soil. Therefore, the growth of the plant depends on the quality of soil.
 Formation of Soil
Soil is formed from rocks by weathering. Rocks are broken down into small pieces due to heat of the Sun, more...
 Separation of mixture
Interconnection of the different states of the matter
SOLID  LIQUID GAS
Releasing heat releasing (heat)
Melting (heat) vaporization (heat)
The above mentioned examples are physical change that can be brought back either by giving or loosing heat- Physical change is reversible. Burning of paper is a chemical change as ash can't be brought back to paper more...
 Introduction
Everything, which we see around us is called the matter. Matter is made up of atoms and atoms are made up of electrons, protons, and neutrons. There are three states of matter, solid, liquid and gas. The properties of solid, liquid and gas states of a same matter are different. The atoms in the solid are tightly packed in comparison to the structure of atoms in liquid and gas. In this chapter, we will study about the properties of different types of matter.
Matter
Anything which occupies space and has mass is called matter. Amount of matter present in a body is called the mass of the body. Mass of a body is constant and remains same, even in the space. Volume is the amount of space, which is occupied by more...
LEARNING OBUJECTIVE
This lesson-will help you to:—
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