Science, unit 7, unit 8

 Lesson- 7

Our Environment

Main Points to Remember

👉 Environment is the place where we live in. It includes all the living and nonliving

components of the surroundings.

👉 The degradation in the quality of environment is called environmental pollution.

👉 There are three types of environmental pollution; water pollution, air pollution

and soil pollution.

👉 Environmental pollution is caused by;

– Lack of awareness in the people.

– Improper management of domestic animals

– Improper management of wastes.

– Smoke from vehicles and industries.

– Lack of proper drainage system.

– Deforestation.

👉 The environment can be kept clean by;

– Increasing the awareness of the people.

– Proper management of domestic animals.

– Proper management of wastes.

– Using smoke free chimneys and vehicles

– Proper drainage system.

– Afforestation and forest conservation programmes

Exercise

1. Fill in the blanks with suitable words.

Answer 👉 

a. Clean water is essential for a healthy life.

b. Defecating near the river causes water pollution.

c. Burning plastics causes air pollution.

d. We can minimize pollution by increasing public awareness.

e. Organic wastes must be collected to make manure.

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

a. Dirty environment causes many diseases.

b. Non-degradable waste causes the soil pollution.

c. We have to free domestic animals to keep our house and surrounding clean.

d. We can defecate in open places.

e. A smoke chulo should be used in kitchen to reduce smoke.

Answer 👉 

a. True

b. True

c. False (We need to take care of domestic animals and provide proper shelter and sanitation to keep our house and surroundings clean.)

d. False (Defecating in open places is unhygienic and can contribute to environmental pollution.)

e. True

3. Answer the following questions.

a. What is environment ? Write down any four components of environment.

👉 The environment refers to the natural surroundings or the conditions in which living organisms exist. Four components of the environment are air, water, land, and living organisms.

b. What is environmental pollution?

👉 Environmental pollution refers to the introduction of harmful substances or pollutants into the environment, resulting in detrimental effects on living organisms and the ecosystem.

c. Define the following.

i) Air pollution: Air pollution is the presence of harmful substances or pollutants in the air, such as gases, particulate matter, and chemicals, which can negatively impact the quality of air and human health.

ii) Water pollution: Water pollution refers to the contamination of water bodies, such as rivers, lakes, oceans, and groundwater, with pollutants, including chemicals, toxins, and waste materials, making it unsafe for consumption and harmful to aquatic life.

d. Write down any three causes of environmental pollution.

Three causes of environmental pollution:

• Industrial activities and emissions
• Improper waste disposal and littering
• Deforestation and habitat destruction

e. Write down any three ways of keeping the environment clean.

Three ways of keeping the environment clean:

• Proper waste management and recycling
• Conserving energy and reducing carbon emissions
• Planting trees and promoting green spaces

f. What should we do to the degradable wastes?

👉 Degradable wastes should be properly managed and disposed of. They can be composted or treated in ways that allow them to break down naturally without causing harm to the environment. Recycling and reusing degradable materials whenever possible is also a good practice.

g. What will happen to us if we lived in a dirty environment ?

👉 If we lived in a dirty environment, several negative consequences could occur:

• Increased risk of diseases and health problems due to exposure to pollutants and contaminants.
• Degradation of living conditions, leading to a decrease in overall well-being and quality of life.
• Loss of biodiversity and disruption of ecosystems, affecting the natural balance and functioning of the environment.
• Impacts on air and water quality, resulting in respiratory issues and waterborne diseases.
• Overall, living in a dirty environment can have detrimental effects on our physical health, mental well-being, and the overall sustainability of our surroundings.

4. Sketch a figure of a clean environment and colour it.

👉 Answer yourself

 Lesson - 8

Types of Matter

Main Points to Remember

👉 Anything that occupies space and has mass is called matter.

👉 The matters are made by tiny particles and are known as objects or substances.

👉 The matter exist in three states. They are solid, liquid and gas.

👉 The matters are of different types; sinking and floating, soluble and insoluble and transparent and opaque.

👉 The objects that dip on the bottom of water are sinking objects and the objects that remain on the surface of water are called floating objects.

👉 The objects that dissolve in water are called soluble and the objects that do not dissolve in water are called insoluble objects.

👉 The objects through which light can pass are called transparent objects and the objects through which light can not pass are called opaque objects

Exercise

1. Fill in the blanks with suitable words

Answer 👉 

a. The matters have mass and occupy space.

b. A liquid substance has definite volume but no definite shape.

c. Light can pass through transparent objects.

d. Air is a mixture of gases.

e. The substances lighter than water float on it.

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

a. The liquid substances flow from a higher level to a lower level.

b. The substances heavier than water floats on water.

c. A thin plastic is a transparent object.

d. Soil is not soluble in water.

e. We can see outside from the window fitted with a glass.

Answer 👉 

a. True

b. False (Substances heavier than water sink in water.)

c. True

d. True

e. True

a. What type of substances sink in water? Give any three examples.

👉 Substances with higher density than water sink in water. Examples include iron, lead, and rocks.

b. Can we find the taste of stone when a soup is made by boiling stone in water? Why?

👉 No, we cannot find the taste of stone when a soup is made by boiling a stone in water. Stone is an inert material that does not dissolve or impart flavor to the water.

c. Give any three examples of floating objects.

👉 Three examples of floating objects are plastic bottles, wooden logs, and foam.

d. We can not see out from a wooden door, why?

👉 We cannot see out from a wooden door because wood is an opaque material that does not allow light to pass through it.

e. Give any three examples of opaque objects.

👉 Three examples of opaque objects are metal, stone, and cardboard.

f. What are transparent objects? Give any three examples.

👉 Transparent objects are objects that allow light to pass through them, enabling us to see clearly through them. Three examples of transparent objects are glass, clear plastic, and water (in a pure form).

4. Draw a picture of a boat floating on a lake and color it.

👉 Answer yourself