Roman numerals originally came from Etruscan numerals which were changed. The Roman numerals came in to use from 4th century B.C.
Historical Preview
Roman numerals originally came from Etruscan numerals which were changed. The Roman numerals came in to use from 4th century B.C.
QUICK CONCEPT REVIEWWe use numbers every day. When we get up in the morning we see the clock and read the time with numbers. We wait for our bus number to go to school. We go to our class say class 5 or 6. We learn mathematics in the school. We count money using numbers only.Do you know, what are the numbers (0 1 2 3 4 5 6 7 8 9) which we use everywhere called? These are the Arabia.But apart from these numbers, we use some symbols too which represent mathematical values. This numerals are the Roman numerals.Roman numerical system uses combination of letters from Latin alphabets to present mathematical numbers.In this chapter we shall learn about the Roman numerals.In Roman numeral system, system, symbols are used to represent the numbers.Rules for Roman numerals:
The first three numbers (1, 2. 3) are represented as \[\to \] I, II and III.
The symbol for 5 is V.
III. One symbol cannot be used more than thrice continuously. That is why we do not write 4 as IIII this is wrong.
If a letter is placed before the letter of greater value then subtract if from the greater number. For example, I represents 1 and V represents 5, so when IV is written this means 5 – 1 = 4. So IV represents 4.
If one or more different letters are there after a letter of greater value. Then add them all.
For example for ten is X.
The symbol for ten is X.
VII. If a letter repeats itself, then add the letter that many times. For example XXX = 10 + 10 + 10 =30 VIII. Only one number can be subtracted from one number. For example: It will be wrong to write 13 = IIXV (15 – 1 – 1). 13 will be written as XIII.
A bar or line on a number increases its value by 1000 times. For example: XV = 15 and \[\overline{XV}\] = 10000 + 5000 = 15000.
Real - life Examples In some watches or clocks you can see the Roman numerals on the more...
LERNING OBJECTIVES This lesson 'will help you to:-
Learn about the basics of ecosystem.
Study about different types of ecosystem.
Understand and study about different food chains and food webs.
Learn and understand the relationship between different food chains.
Real-Life ExampleOur country India has diverse climatic and accordingly we find different plant and animal species. Example: In hot and dry Rajasthan we will find small shrubs and cacti plants and the prominent animal seen id camel. On the other hand, in Lehn in Kashmir, extreme cold temperature prevails and there is hardly any vegetation and the animal mostly seen is yak.QUICK CONCEPT REVIEW Ecosystem:
An ecosystem is a community of living things interacting with each other and their surroundings.
An ecosystem can be anything from a piece of rotting wood to a huge swamp. In every ecosystem, each organism is dependent on the other organism as well as on the surrounding.
It is a complex set of relationship among the living resources, habitats and residents of an area. It includes plants, trees, animals, fish, birds, micro- organisms, water, soil and paper.
Ecosystems vary greatly in sizes and the elements that make them up, but each is a functioning unit of nature.
If one part of an ecosystem is damaged or disappears, it has an impact on everything else.
A healthy ecosystem means that all the elements live in balance and are capable of reproducing them.
BIOME: A biome is a very specialized ecosystem that only exists in a certain area or climate. They are identified by factors like temperature, rainfall, soil type and altitude.
Various types of biomes present in the world are given in the table below.
Learn about basic concepts of sound like Doppler Effect.
Real-Life Examples
When look into the mirror, we see ourselves. This is the example of reflection of light from the mirror which is producing the image of our face on the screen.
People who tend to listen to loud music on a regular basis start listening loud due to the deafness of ears.
QUICK CONCEPT REVIEW LIGHTPhotonPhotons are tiny little particles of light, far too small (to be seen individually. All light is made up of photons they are the fundamental particles of fight. The photon is massless and has no electric charge. In empty space the photon travels at the speed of light. The concept of the photon was developed by Albert Einstein.Wavelength and FrequencyOne of the characteristics of light is that it behaves like a wave. As a result, light can be defined by its wavelength and frequency. The frequency is how fast the wave vibrates or goes up and down. The wavelength is the distance between two peaks of the wave. Frequency and wavelength are inversely related, meaning that a low frequency wave has a long wavelength and vice versa. LIGHT
Light has no mass and is not really considered matter.
Light is a form of energy made of photons.
Light is uniq use in that it behaves like both a particle and a wave.
Depending on the type of matter it comes into contact with, light will behave differently.
Sometimes light passes directly through matter, like through air or water. This type of matter is called transparent.
Other objects completely reflect light, like an animal or a book. These objects are called opaque.
A third type of object does both to some extent and tends to scatter the light. These objects are called translucent objects.
Amazing Facts
The sun is almost 93 million miles away from the earth. It takes around 8 minutes for light to get from the sun to the earth. It takes around 1.3 seconds for light to go from the moon to the earth.
Dog can hear sound at a higher frequency than humans, allowing them to hear noise that we can’t.
LEARNING OBJECTIVES This lesson will help you to:—
Learn about the human body and its organ system.
Know about food and digestion.
Learn and study about teeth and microbes.
Understand and learn about importance of sanitation and related diseases.
Learn about nutrition.
QUICK CONCEPT REVIEW Human Body
The human body is made up of a head, neck, torso, two legs. The average height of an adult human is about 5 to 6 feet.
There are many systems in the human body:
Circulatory System (heart, blood, vessels).
Respiratory System (nose, trachea, lungs).
Immune System (many types of protein, cells, organs, tissues).
Skeletal System (bones).
Excretory System (lungs, large intestine, kidneys).
Urinary System (bladder, kidneys).
Muscular System (muscles).
Endocrine System (glands).
Digestive System (mouth, oesophagus, stomach, intestines).
Nervous System (brain, spinal cord, nerves).
Reproductive System (male and female reproductive organs).
Your body is made up of four main types of bones. Long bones such as the bones in your arms and legs, short bones such as the bones in your hands, feet and spine, flat bones which protect your organs provide a place for muscles to attach, and irregular bones, which are simply all the bones that are not long, short or flat.
Your body is constantly breaking food down in the digestive system, and then using the pieces to build, repair, and grow your body.
The job of your heart is to pump blood through your body. Even in your sleep, your heart keeps beating, or pumping blood. If it stopped, you would quickly die. Your heart is divided into two sides. The left side of your heart is filled with oxygen-rich blood, while the right side of your heart is filled with oxygen-poor blood.
Just like a city with hallways and roads, your body has blood vessels, arteries and veins that help move things around. Most of the cells inside your body do not move. If a cell is hungry or needs to get rid of waste, it can't simply move itself to the part of your body where it needs to go. Instead, your body must bring the food to your cells and take the waste away from them.
Oxygen is used by your cells as it performs the functions of life. As your body uses oxygen, your cells produce another gas known as carbon dioxide. Too much carbon dioxide can be toxic, and even deadly. For this reason, it is important that your body has a way to get rid of it.
The main organs in your respiratory system are your more...
Learn about the movement of planets in the universe.
Real-Life Example
In the night if we see the sky closely, we can see several shooting stars. These shooting stars are actually meteors that are burning.
Hysterical Preview
The names of all the planets are in roman as a group of roman people discovered them.
QUICK CONCEPT REVIEW As we all know we live on earth. Earth is a planet. We also see birds, trees and animals that live on earth. But have you ever thought that, the universe contains earth only or there are other things also besides the earth?There is unlimited place around the earth and this space is called universe. It includes stars, planets and other things.There are other planets and satellites which revolve around the sun and together them from the solar system.The sun and the planets moons, asteroids, comets and the other things revolving around the sun together constitute the solar system.FORMATION OF SOLAR SYSTEM The formation of solar system began some 4.6 billion years ago when a cloud of dirt and gases was formed. This cloud started collapsing into its centre due to gravitational force. The sun was formed at the centre while the rest flattened into a disc of loose dust, out of which the planets, asteroids and solar bodies were formed.In this chapter we shall about the sun and its family members.SUNSun is a star. As we all know that it gives us light and heat. Our life depends upon it.The distance of sun from earth is greater than the distance of earth from moon. The things start appearing smaller than their actual size as they start moving away from us. So as the sun is at more distance as compared to the moon from earth, it looks smaller in size. There are stars bigger than the sun but they are not visible to us as they are very far away from us.Sun is at the centre of the solar system and all the planets revolve around it. The circles or the path followed by the planets to revolve around the sun is called an orbit. All the planets move in their own orbits.The earth takes 365 days to take one round of more...
LEARNING OBJECTIVES This lesson will help you to:—
Study about different fuels used in vehicles.
Study about the consumption of fuel by different vehicles.
Learn and study about various adventurous trips on rough terrains.
observe and study about sky
Study about man-made spacecrafts and their use.
Learn and study about monumental heritage of India.
Real-Life Example
When we buy any vehicle, the first thing we ask the salesperson is about its mileage.
Diesel care are being preferred these days because they are more fuel efficient, economical and eco-friendly.
QUICK CONCEPT REVIEW Fuels used in vehiclesToday's vehicles run on a variety of fuels, some of which you probably aren't aware of. While it's true that the vast majority of vehicles run on petrol, the technology to burn other fuels to meet our transportation needs does exist, with specific advantages and disadvantages for each.PETROL
Petrol is the most common fuel used in cars today.
This specialized fossil fuel is designed for four- stroke engines like the ones found in common cars.
It allows for quick starting, fast acceleration, easy combustion and quiet operation.
The hydrocarbons contained in petrol and its production of carbon dioxide when burned contributes to pollution, smog and global warming.
Although it is the most readily available fuel, it is considered to be a temporary source of fuel because of its cost, environmental effects and limited resources.
DIESSEL
Diesel fuel is widely used in transport vehicles such as tractor-trailer trucks, buses, boats and trains.
This fossil fuel is also non-renewable, like petrol.
Although it contributes less carbon dioxide to the environment, diesel creates more organic compounds and nitrous oxide that causes smog.
Diesel vehicles tend to last longer than petrol vehicles, and they have 30 percent better fuel efficiency than the average petrol vehicle.
COMPRESSED NATURAL GAS
Petrol and diesel engines can be converted to run on compressed natural gas, or CNG.
CNG is a clear, odorless and non-corrosive gas that can be used in liquid or gas form to run a combustion engine.
Vehicles fitted with a CN6 fuel system can be expected to produce 80 percent less ozone-forming emissions than petrol burning cars.
Other fuels such as liquefied petroleum - propane and ethanol are also being used in some technologically advanced vehicles being developed in developed countries. These fuels are eco-friendly and less expensive in comparison to petrol and diesel. These however still require much technological advancements to be used as a more...
QUICK CONCEPT REVIEW As you already know that we live on earth. You have also studied about different things that the earth and its atmosphere provides us. We grow our food on earth. We also get many valuable things such as: coal, petroleum and water from earth. The atmosphere of earth provides us oxygen to breathe.We already know that there is a system called solar system which comprises of the sun and all the planets. All the planets revolve around the sun. In this chapter we shall learn some more movements of earth.Amazing Fact
Northern hemisphere contains most of earth’s land area. Southern hemisphere is 99% water.
MOVEMENTS OF EARTH Like all other planets, earth also revolves around the sun. The movement of earth around the sun is called revolution. Earth revolves from west to east in an elliptical orbit.Therefore the distance between earth and sun keeps on changing. The earth takes one year to complete its revolution around sun.Revolution of earth is also called annual motion as the earth takes one year to complete one revolution.Elliptical: It means an oval shape. Many heavenly bodies revolve in an elliptical path in the galaxy such as all the planets in solar system.Orbit: It is the path followed by a planet.But do you know there is one other motion associated with earth. Apart from revolving around the sun the earth also spins around itself. This spinning of earth around itself is called Rotation. The earth rotates from west to east. It completes its one rotation in 24 hours i.e. a day.When we say that earth rotates or spins around itself, we say that it rotates on its axis. Axis is an imaginary line on which the earth rotates. It links the two poles.What are Northern and Southern hemispheres?Hemisphere means half of a sphere. Northern hemisphere is in north of equator whereas southern hemisphere is in south of equator. The earth is divided in these two hemispheres.Equator: It is an imaginary line drawn around the earth equally distant from both the poles, dividing the earth into northern and southern hemispheres.WHAT ARE NORTH AND SOUTH POLES?The northernmost point of earth is called North Pole and more...
get the knowledge about what a shelter is and what s its importance.
Know that different people build different types of houses according to their needs and the environmental conditions of the place.
Know about the need of living close to each other.
Study about the need for shelter in animals, birds and insects too.
Understand what happens when people lose their homes for one the other reason.
Historical Preview
Ancient Greeks built their house by using the bricks made of mud and then dried their houses around the courtyard so as to let air circulate.
QUICK CONCEPT REVIEW In the study of our environment and our surroundings we have learnt about our different needs. We have discussed food, importance of games and need of water etc. There is one more basic need of all the living things and that is ‘’shelter’’.In simple language we can say, that the place which gives us protection from rain, storms and animals etc. us protection from rain, storms and animals etc. is called our shelter. So the place where we live is our shelter. In common language we call it our home/house.We move from place to place. There is a difference in the types of houses according to place, locality and weather condition of that place. There are different types of houses built according to the needs of people which are generally associated with the weather conditions and availability of the materials.Difference in climatic: The type of a house builtIn a particular area depends upon the climatic condition of that place. For example:In the rainy areas the roofs are made thick and sloping so as not to let the water collect on it. By using the slanting roofs, the rain water gets cleared easily and it does not collect over the roofs. The houses made in the snowy areas are also of similar type.
Houses are made of wood in earthquake prone areas to minimize the damage and for security.
The houses made in the hot climate areas are often painted with light colors so that they do not absorb sunlight.
There are different types of houses and buildings made in the countries with very cold weather. In these houses the pipes carrying warm water are fitted within the walls. When the hot water is circulated, it imparts heat to the room and thus warms it.
But sometimes while living in the same climate, some people have different types of houses. The differences in the more...
Understand that our body needs food for energy and for growth.
Examine different types of food like fruits, vegetables and cereals.
Understand how we can fall ill if we do not keep our food safe and clean.
QUICK CONCEPT REVIEW In this chapter we shall learn some more things related to food. As we already know that by having a contaminated and spoiled food we can fall ill. In this chapter we shall learn how the food gets spoils and how we can prevent our food from getting spoiled.Historical preview
There were no tomatoes in Italian food. Peanuts in Thai food, or chili peppers in Indian food in the year 1450.
WHAT DO WE MEAN BY SPOLED FOOD?Spoilage of food is a state of deterioration of food in which the food no longer remains suitable for human consumption. So the spoiled food means that the food can no longer be taken as it has got very much deteriorated.WHEN AND HOW DOES THE FOOD GET SPOILED?The food gets spoiled because of the attack of microorganisms depend upon food and they feast on the food when it is not attended. Worms, insects and bugs also spoil. One of the major causes of food spoilage is the storage of food in warm places.HOW DO WE KNOW THAT THE FOOD HAS SPOILD?As soon as there is change in colour, flavor, odor and appearance, the food has started to get spoiled. The first thing which comes to our notice is the change in colour or the appearance of the food. The food either gets softer or harder than its normal state. For example, the fruits kept unattended for a few days will become softer. There is also a foul smell from a rotten food. Some food items such as biscuits, pickles, cooked vegetables and boiled milk, etc., take some time to get spoiled as compared to uncooked vegetables and flesh, unattended fruits and milk. When we keep the food in a warm place for a long time there is growth of food spoiling micro-organisms at a faster rate. That is why the food kept in the refrigerator does not get spoiled very soon, as the temperature inside it is lower.HOW CAN THE FOOD BE PRESERVED?By taking some simple precautions we can save our food against spoiling. Some of these are:
The major cause of the food spoilage is its improper storage. If we keep the more...
Learn about the importance of team spirit in games.
Study about gender and class stereotyping in play.
Study about local and traditional games.
Learn about changing pattern of local games.
Study and learn about the changing nature of leisure.
Learn about the art of blowing and different techniques of breathing.
Learn about the role of labour in our society.
QUICK CONCEPT REVIEW Team; A group of players forming one side in a competitive game or sport is called a team.Teamwork: The efforts undertaken by every team member for the achievement of the team's objective is known as teamwork.Team Spirit: An enthusiastic attitude towards working or playing together with other people as a team is known as team spirit. Team spirit is about supporting your team, respecting others and most of all encouraging your team mates.T - Trying your bestE - EncourageA - AchievementM - Must always show team spiritS - Supportingp - Participating I - Impossible (it's impossible to winif you have no team spirit)R - Respect I - Important (it's important to show team spirit)T - Together (we work together)
Playing in a team with the correct team spirit extremely important for winning the game.
A team is headed by a captain. A captain has a significant responsibility for strategy and teamwork while the game is in progress on the field.
Usually the teams of a particular sport are different for men and women.
Example: The cricket team representing a country is different for men and women.
Teams play at national and international levels the international level they compete with teams from other countries whereas at the national teams from different states compete with each other.
Not all games are played in teams.
Every country has a game that is recognized as it's all national game.
For example. Hockey is the national game of India.
Even today, gender stereotyping can be seen different plays. Men are given preference over women in the games, as it is supposed that play requires the players to be strong and masculine. And women are considered to be the weaker gender. Even today, women teams are struggling to get the same appreciation as obtained by their male counterparts despite of having abundant talent.
One of the characteristics of light is that it behaves like a wave. As a result, light can be defined by its wavelength and frequency. The frequency is how fast the wave vibrates or goes up and down. The wavelength is the distance between two peaks of the wave. Frequency and wavelength are inversely related, meaning that a low frequency wave has a long wavelength and vice versa.
LIGHT
QUICK CONCEPT REVIEW
Human Body
Sun is a star. As we all know that it gives us light and heat. Our life depends upon it.
The distance of sun from earth is greater than the distance of earth from moon. The things start appearing smaller than their actual size as they start moving away from us. So as the sun is at more distance as compared to the moon from earth, it looks smaller in size. There are stars bigger than the sun but they are not visible to us as they are very far away from us.
Sun is at the centre of the solar system and all the planets revolve around it. The circles or the path followed by the planets to revolve around the sun is called an orbit. All the planets move in their own orbits.
The earth takes 365 days to take one round of more... 
Amazing Fact
Revolution of earth is also called annual motion as the earth takes one year to complete one revolution.
Elliptical: It means an oval shape. Many heavenly bodies revolve in an elliptical path in the galaxy such as all the planets in solar system.
Orbit: It is the path followed by a planet.
But do you know there is one other motion associated with earth. Apart from revolving around the sun the earth also spins around itself. This spinning of earth around itself is called Rotation. The earth rotates from west to east. It completes its one rotation in 24 hours i.e. a day.
When we say that earth rotates or spins around itself, we say that it rotates on its axis. Axis is an imaginary line on which the earth rotates. It links the two poles.
What are Northern and Southern hemispheres?
Hemisphere means half of a sphere. Northern hemisphere is in north of equator whereas southern hemisphere is in south of equator. The earth is divided in these two hemispheres.
Equator: It is an imaginary line drawn around the earth equally distant from both the poles, dividing the earth into northern and southern hemispheres.
WHAT ARE NORTH AND SOUTH POLES?
The northernmost point of earth is called North Pole and more... 
Some food items such as biscuits, pickles, cooked vegetables and boiled milk, etc., take some time to get spoiled as compared to uncooked vegetables and flesh, unattended fruits and milk. When we keep the food in a warm place for a long time there is growth of food spoiling micro-organisms at a faster rate. That is why the food kept in the refrigerator does not get spoiled very soon, as the temperature inside it is lower.
HOW CAN THE FOOD BE PRESERVED?
By taking some simple precautions we can save our food against spoiling. Some of these are:
