Science, unit 11, unit 12

 Lesson - 11

The Earth

Main Points to Remember

👉 The earth is the living place of all animals and plants.

👉 The earth is made by three different parts; They are lithosphere, hydrosphere and atmosphere.

👉 Lithosphere covers about one fourth of the earth’s surface. It is the land form made by plains, hill, valleys and mountains.

👉 Hydrosphere contains about three fourth of the earth’s surface. It is the water part of the earth made by lakes, ponds, rivers and oceans.

👉 Atmosphere lies around the earth’s surface and is made by many gases, smoke, dust particles and water vapour.

👉 The earth’s surface is made by rocks and soil.

👉 The rocks are hard or soft and found in different colours.

👉 Soft rocks Generally, break and mix with humus and forms soil after a long period of time.

👉 The soil contains decayed organic matters (humus), air, water and small particles of rocks.

Exercise

1. Fill in the blanks with suitable words.

Answer 👉

a. The earth is spherical but slightly flattened at the poles.

b. About three-fourths part of the earth’s surface is covered by water.

c. The land part of the earth is called as lithosphere.

d. Snow covered high lands with more slope are Himalayas.

e. Hills are the land with slopes.

2. Write ‘True’ for the correct sentences and ‘False’ for the wrong ones.

a. About half of the earth’s surface is made by land.

b. Atmosphere is made by gases, water vapour, smoke and dust particles.

c. The flat surface of land surrounded by hills is called a valley.

d. Hardness of rock can be checked by scratching.

e. The soil does not contain any organic matters in it.

f. The broken part of rocks along with humus forms soil.

Answer 👉 

a. False

b. True

c. True

d. True

e. False

f. True

3. Answer the following questions:

a. What is the shape of the earth?

Answer 👉 The shape of the earth is spherical, but slightly flattened at the poles.

b. What are the three parts of the earth? By what the land form of earth is made?

Answer 👉 The three parts of the earth are the lithosphere (land), hydrosphere (water), and atmosphere (air). The landforms of the earth are made by the movements of tectonic plates and erosion.

c. Why do the plain land contain fertile soil?

Answer 👉 The plain land contains fertile soil because it is formed by the deposition of sediments brought by rivers and floods. These sediments contain nutrients that make the soil fertile for plant growth.

d. What is found below the soil? Write down any two uses of that substance.

Answer 👉 Below the soil, we can find rocks or bedrock. Two uses of rocks are construction materials and as a source of minerals.

e. How can you say whether the soil contains air or not? Write in brief.

Answer 👉 We can say whether the soil contains air or not by observing its texture and structure. Well-aerated soils have a loose texture and good drainage, allowing air to penetrate. Poorly aerated soils are compacted and waterlogged, indicating a lack of air.

f. How many types of rocks are there? How can we check the hardness of a rock?

Answer 👉 There are three types of rocks: igneous, sedimentary, and metamorphic. The hardness of a rock can be checked by scratching it with another object. If the rock scratches easily, it is considered softer, while harder rocks will not scratch easily. The Mohs scale is commonly used to measure the hardness of minerals and rocks.

Lesson - 12

Information and communication

Technology

Main Points to Remember

👉 The facts about many things we get from various resources are called informations.

We get informations by various means of information.

👉 The process of exchanging information is communication.

👉 We can get the information by letters, radio, television, newspapers and telephone.

👉 Now a days computers connected to the internet network have been widely used as a means of information and communication technology (ICT).

👉 We can have one-way communication by letters, radio, television, news paper, speech, etc.

👉 We can have two-way communication by using telephone, e-mail, voice chat through internet, seminars, etc.

1. Fill in the blanks with suitable words.

Answer 👉 

a. The fact we get from various resources is information.

b. Radio is a means of one-way communication.

c. Telephone is a means of two-way communication.

d. A letter is a message written in a piece of enveloped paper.

e. A television station sends the information by satellite.

2. Write ‘True’ for the correct sentences and ‘False’ for the wrong ones.

a. A printed paper with information is newspaper.

b. E-mail is a method of one-way communication.

c. The process of exchanging information is communication.

d. The station prepares programmes for radio.

e. We can use computers without internet to collect various informations about the world.

Answer 👉 

a. False

b. False

c. True

d. True

e. True

3. Answer the following questions:

a. What is communication? Write down any three means of one-way communication.

Communication is the process of exchanging information, ideas, or messages between individuals or groups. Three means of one-way communication are:

• Television broadcasts
• Public announcements
• Newspaper advertisements

b. Is the bell ringing in your school a means of information? Why ?

The bell ringing in a school is not a means of information but rather a means of signaling or indicating the start or end of a class or break.

c. What is telephone ? What type of means of communication is it?

 Telephone is a telecommunications device that allows voice communication over long distances. It is a two-way means of communication, as it enables conversations between two or more individuals in real-time.

d. What is newspaper ? Write down the name of any three newspapers that you have read or seen.

A newspaper is a printed publication that provides news, articles, and other information to the public. Three newspapers that I have read or seen are:

The New York Times

The Guardian

The Times of India