7th Class

Learning Objectives

Different types of nutrition

Nutrition in amoeba-digestion is intracellular,

Nutrition in humans

Nutrition in ruminants- has four chambered stomach

Different types of teeth in relation to food habits.

Humans have two sets of teeth- milk teeth and permanent teeth.

   INTRODUCTION Plants make their food by the process of photosynthesis, but animals cannot make their food themselves. Animals get their food from plants. Some animals eat plants directly while some animals eat plant eating animals. Thus, animals get their food from plants either directly or indirectly. All organisms require food for survival and growth. Requirement of nutrients, mode of intake of food and its utilization in body are collectively known as nutrition. Animals are heterotrophic in nutrition as they cannot make their own food. Euglena is an more...

Learning Objectives

Introduction

All living things need food.

The process of utilization of food by an animal to obtain energy for growth and development is known as nutrition.

Autotrophic mode of nutrition

Heterotrophic mode of nutrition

Some plants are parasites, saprophytes and symbiotic.

    INTRODUCTION Food is the most important and basic thing for life. Carbohydrates, proteins, fats, vitamins and minerals are the components of food. These components are necessary for all living beings. All plants and animals require food for their growth and to get energy. The process of utilization of food by an animal to obtain energy for growth and development is known as nutrition, Plants make their food themselves but animals cannot. Hence, animals depend directly or more...

Learning Objectives

To understand concept of soil formation

To understand soil profile and composition of soil

To learn about different types of soil

To study soil erosion-its causes and preventions

To learn about soil pollution –its sources and control.

Soil is a precious gift from nature. Soil supports life on earth. Most people think soil as a layer of dirt and mud. However this layer of mud and dirt is actually filled with life. Food we eat, fibre we use to make fabric, habitat for various organism etc. is provided by soil. If you closely observe a freshly dug pit you may see various creatures like earthworm, ants, beetles etc. Soil provides nutrients to the plants and support their growth. All living organisms depend directly or indirectly on soil. Let’s learn more about soil. more...

Learning Objectives  

To learn about physical and chemical changes

To understand characteristics of physical and chemical changes

To understand the process of rusting of iron and methods of its prevention

To study crystallization process and its applications

  We have learnt in previous class about different changes around us like periodic and non-periodic, slow and fast changes, reversible and irreversible changes around us and their causes. Every change has a cause for example days change tonight because of rotation of earth around the sun, melting of ice is due to heat supplied. There are changes in everything. When we eat, breathe, talk or sleep changes take place in our body Changes can be in shape, size, temperature, state of substance etc. In this section we will learn about the classification of the changes around us into two main categories- Physical and chemical changes.   more...

Learning Objectives

To study the concept of acids, bases and salts

To study different indicators and their color changes on different substances

To understand neutralization reaction and formation of salts

To study neutralization by taking some examples from everyday life.

To study uses of acids, bases and salts.

  We have learnt in previous class about the classification of substances based on their physical properties like appearance, solubility, hardness etc. Substances can also be grouped on the basis of their taste as sweet, salty, sour or bitter. Have you ever tasted lemon without adding water and salt? Or have you noticed the slippery touch of soap? Lemon juice, tamarind, raw mango etc. taste sour, some substances like baking powder tastes bitter. Common salt tastes salty These tastes are the characteristics of three different types more...

Learning Objectives

To study natural fibers obtained from animals-Wool and silk

To learn about animals giving wool

To study each step involved in making wool from fiber

To understand life cycle of silkworm

To study the process of formation of silk from cocoons

To understand the health hazards of wool and silk industry

  Fibre are hair-like material that form the building blocks from which yam and fabric are made. Fibres obtained from plants and animals are called natural fibres. The history of fibres is as old as human civilization. Most clothing worn in the Stone Age was probably made from the skins of animals. It is also likely that some clothing was made by weaving grasses and other plant life. You have leamt in previous class about type more...

Learning Objective

Introduction

Winds and sir pressure

Wind currents and Manson

Storms

Cyclones

Damages caused by cyclones

Safety measures for cyclones

  INTRODUCTION We have heard many times about the natural disasters. The natural disaster include storms, cyclones, earthquakes, etc. which can cause   lot of damage to human life, animals and property. In this chapter we shall study about what are winds, storms, cyclones and hurricanes? How are they formed and why are they so destructive?   WINDS AND AIR PRESSURE Moving air is called wind. The difference in the air pressure which is caused by the unequal heating of different parts of the earth causes wind. Now let us see how wind blows? more...

Learning Objectives

Introduction

Heat and temperature

Temperature measuring scales

Temperature measuring instrument thermometers

Heat transfer

• Conduction
• Convection
• Radiation

Conductors and insulators

  Introduction We wear woolen clothes during winters when it is cold outside. Woolen clothes keep us warm. In summers we feel hot inside the house as well. How do we know whether an object is hot or cold? We find some objects are hotter than others while some are colder than others. We often decide it by touching the objects, in the case of a hot body, heat flows into our body while in case of a cold body heat flows out of our body.   HEAT AND more...

Learning objectives

Introduction

Slow and fast motion

Relation between distance and time: speed

Types of speed

• Uniform speed
• Non-uniform/variable speed
• Average speed

Time

Time measuring devices

• Sundial
• Sand clock/hour glass
• Water clock

Measuring of time using periodic motion: simple pendulum

Unit of time

Graph: Distance versus time

  INTRODUCTION The famous scientist Albert Einstein said "Nothing in the universe can be at absolute rest". This means that all objects are executing some types of motion. A body is said to be in motion whenever it changes its position with respect to its surroundings. When a body is in motion there is often a need more...

Learning Objectives  

Introduction

Work

Types of work

Energy

Mechanical energy-Kinetic and Potential

Law of conservation of energy

Different forms of energy and their inter conversion

  Introduction In everyday language, we often term 'work' and 'energy'. A child sitting and doing his/her homework, a laborer breaking a wall, a man making a presentation on PC, a farmer plugging his fields, all are said to be doing some work. A person who can do more work is said to have more energy. In this chapter we study the actual meaning of work and energy and how they are related to each other.   WORK When a force is applied on a body, and it displaces the body through some distance, then work more...