CBSE Class 7 Science:
The syllabus of CBSE Class 7 Science can be divided into many topics such as
- Food
- Materials
- The world of living
- Moving things, people and ideas
- Natural Phenomena
These topics in detail are below:
- Food:
This chapter concentrates on how plants and animals get their food, how do animals utilize their food, types of nutrition, nutrition in amoeba and human beings, etc.,
Nutrients in plants:
Each and every organism like plants, microbes, animals and humans require nutrients like vitamin, proteins, fat, and carbohydrates in some form. These nutrients help the plants to grow and repair their own damaged parts. Unlike humans and animals, plants obtain their nutrition by various modes such as autotrophic mode or heterotrophic mode. Autotrophic mode is a mode which can synthesize their foods by the process of photosynthesis. Heterotrophic mode is a mode which cannot synthesize their own foods and depend upon other organism for their nutrition.
Nutrition in animals:
This is widely divided as digestion in animals, digestion in ruminants and digestion in amoeba.
Digestion in animals:
Animals cannot synthesize their own food and thus depend upon other organisms like plants or other smaller animals for food. Based on the food consumed, the animals can be classified as herbivores, carnivores, and omnivores. Thus animals exhibit heterotrophic mode of nutrition.
Digestion in ruminants:
Ruminants are nothing but herbivores or grass eating animals. Plants cells contains rich source of cellulose which is an important component in the diet of these herbivores animals. Humans cannot digest this cellulose. The special things about ruminants are, they swallow the food without chewing and then bring it back from the stomach and chew it leisurely.
Digestion in amoeba:
Amoeba is a microscopic unicellular organism. They are found under the bottom of the fresh waters, ponds, pools, gutters, and in muddy waters. Amoeba is an omnivores organism which feeds on microbes, plants and other smaller organism. Amoeba does not possess any mouth but has a sense of ability to find out which are food particles and which are not. An amoeba engulfs its prey along with a droplet of water in the food vacuole inside the cytoplasm.
Examples:
- Why do the organisms need food?
Answer: Organisms need food build their body, get energy, repair and maintain the functions of the body.
- State true or false:
- Digestion of the starch starts in stomach? (T/F)
Answer: False
- Materials:
This chapter covers the topics such as where does our clothing come from, what types of animals are reared to make woolen cloths, What clothes keep us warm, what is heat, temperature, different kinds of materials, classification of substances into acidic, basic and neutral indicators, etc.
Animal fiber-wool and silk:
Silk is a cloth material which keeps us warm during the winter season. Silk is a product which is extracted from the animal or insect called silkworm. Just like silk, wool is also a cloth material which is extracted from the sheeps and goats. It was the first fibre to run into yarn, and it provides more warmth than any other animal fibres.
Temperature and heat:
Temperature is a measure of degree of hotness of the body. The SI unit of temperature is Kelvin (K). The instrument that is used to measure the temperature is Thermometer. When an object is at a different temperature than its surroundings, slowly heat transfer takes place turning the object’s temperature same as that of the surroundings. There are three modes of heat transfer such as convection, conduction and radiation.
Acids, bases and Indicators:
Substances can be classified as acids, bases and neutrals. The chemical nature of any substance which is sour is called as acidic substance. For example: curd
Bases are the substances which taste bitter. They are slippery to touch. For example, soap and lime water. Neutral substance is a substance which does not show acidic or base properties and said to be neutral in nature. Indicators are the substances which are used to test whether the substance is acidic or basic in nature.
Examples:
- Ammonium is found in many household products such as window cleaners, etc. It has a nature of turning red litmus to blue. What is the nature of substance called?
Answer: Basic
- Is the distilled water acidic/basic or neutral?
Answer: Neutral
- The world of living:
This chapter covers the topics such as climate, soil types, adaption of animals to different climate, respiration in plants and animals, herbs, trees and transport of water in trees, excretory system in animals, reproduction system in plants and animals, etc.
Weather and climate:
The day-to-day conditions of a surrounding atmosphere with the respect to the elements like temperature, heat, moisture, rainfall and wind speed is called as a weather of that place.
The average weather pattern taken over a long period is called as a climate of that place. There are different types of climates according different places. They are
- Dry climate
- Moist tropical climate
- Humid middle latitude climate
- Continental climate
- Cold climate
Winds, Thunderstorms, Cyclones:
The natural movement of air, generally in a more furious way blowing in a particular direction is called as wind. Thunderstorm is a storm with a thunder and lightning accompanied with heavy rain. They occur due to the convection of air in the hot and humid tropical areas. Cyclone is a natural calamity which is caused due to difference in the air pressure in the atmosphere. It may develop over the sea and may cause severe damages to the land area with a violently rotating wind.
Soil types and its properties:
Soil is an upper layer of the earth’s crust which is usually composed of a mixture of organic remains, clay and rock particles. There are few important properties of soil such as Absorption of water, moisture in the soil, percolation rate of water in the soil.
Respiration in organisms:
Respiration is a process of inhaling oxygen and exhaling waste products such as carbon dioxide. It takes place in two types as external respiration and internal respiration. External respiration is also called as breathing which involves inhalation and exhalation. Inhalation is the process of taking in air rich in oxygen whereas exhalation is breathing out air rich in carbon dioxide.
Reproduction in plants:
Reproduction is a process of developing their offspring or producing their young ones. Reproduction in plants takes place asexually and sexually. Sexual mode of reproduction takes place between two organisms of opposite sex. Reproductive organs in the plants produce gametes-Ovules (Eggs) and pollen grains. Asexual mode of reproduction is a type of reproduction in which single parent is involved to produce the new off spring. In other words, it can be said as growth of new plant from the existing plant other than the seed.
Examples:
- Name the elements that determine the weather of a place?
Answer: Temperature, rainfall and humidity
- The water holding capacity is highest in _____type of soil?
Answer: Clayey soil
- Moving things, people and ideas:
This covers the topics such as time and measurement of time using periodic events and motion of objects.
Time and speed:
Speed and time can be calculated by a formula such as Speed = Distance / time whereas Time= Distance/ Speed. The SI unit of speed is metre (m) and SI unit of Time is Second. The instruments that are used to measure time is mechanical clocks and simple pendulum.
Graphs:
A graph is a pictorial representation of given sets of datas. Graph makes clear understanding of the datas given instead of any other form. There are different types of graphs such as bar charts, pie charts, line graphs, etc.,
Examples:
- Every object moves with a constant speed? Correct or incorrect?
Answer: Incorrect
- A simple pendulum takes 32 s to complete 20 oscillations. What is the time period of the pendulum?
Answer: Time period: 1.6 seconds
- How things work?
This covers the various topics such as Electric current and its effects, working of an electric bell, a current carrying coil behaves like a magnet, etc.
Electric components:
There are different electrical components available such as cell, switch, wire, bulb, battery, etc., Different symbols are used to represent different components in an electrical circuit. For example, wire allows to current flow from one part of the circuit to another, similarly switch has an operation called ON or OFF. When switch is off current is not transferred into the electrical circuit. Thus, each electrical component has its own functions to perform.
Heating effects of the electric current:
Naturally when an electric current flows through the wire, the wire gets heated up. This is called as heating effects of the electric current. There are factors such as length and thickness of the wire, material of the wire which may affect heating up of the wire.
Magnetic effect of the electric current:
When an electric current flows through the wire, the wire behave like a magnet. This is called as magnetic effect of the current. Always a magnetic field is created around the current carrying wire in a given circuit.
Examples:
- Name any two effects of electric current?
Answer: Magnetic effect
Heating effect
- Do you think that an electromagnet can be used for separating plastic bags from a garbage heap?
Answer: No, electromagnets attract only the magnetic material like iron. So it cannot be used for separating plastic from garbage.
- Natural resources:
This covers the topics such as scarcity of water, water a precious resource, ways to safeguard water resources, etc.,
Water- a precious resource:
It is said that nearly 71% of earth is surrounded by water resources such as oceans, sea, lakes, ponds, moisture, humidity, etc., among which most of them are not suitable for the human consumption. Water which is suitable for the human consumption is called as fresh water.
By nature, water can exist in three forms such as Solids, liquids and gaseous states.
Humans must follow better conservation techniques of water like rain water harvesting system, drip irrigation, bawris, etc.,
Importance of forest:
Forest is a precious resource given by the nature which is area for all types of species forming an ecosystem. Forest areas are the main resources which help in preservation of water on earth. Plants and trees in forest absorb water from the soil through their roots. Thus, it is more necessary to understand the importance of forest and its resources.
Examples:
- State true or false?
- The fresh water stored in the ground is much more than that present in the rivers and lakes of the world.
Answer: True
- Herbs from the ______ layer in the forest.
Answer: Ground layer
Thus, these are topics which are covered in the CBSE Class 7 Science.