Properties of Natural Resources | Class 7 Science Chapter 3 - Perfect Question Answers

Properties of Natural Resources | Class 7 Science Chapter 3 – Perfect Question Answer

Q.1: Fill in the blanks with the appropriate term.
(Temperature, volume, mass, density, humidity, acidic, weight, neutral, shape.)

(a) The capacity of air to hold moisture depends upon the …………… of the air.
Answer: temperature

(b) Water does not have a …………… but has definite ………… and ………. .
Answer: shape, volume, mass

(d) …………….. soil has pH 7.
Answer: neutral

Properties of Natural Resources – Questions Answers

Q.2: Why is it said that :

(a) Air is a homogeneous mixture of various gases.
Ans: Air is made of oxygen, nitrogen, carbon-dioxide, water vapour and dust particles. All these are in different proportions. Therefore air is a homogeneous mixture various gases.

(b) Water is a universal solvent.
Ans: ➧ Water dissolves more things than any other liquid. It can dissolve solids, liquids, and gases. Therefore is why it is called the universal solvent.
➧ Water is used as a solvent in factories, laboratories, foodstuffs and in various types of biological processes occurring in the body such as digestion, excretion, etc.

(c) There is no alternative to water for cleaning purposes.
Answer: Water is a universal solvent. It dissolves most of substances than any other liquid so there is no alternative to water for cleaning purposes.

Q.3: What will happen if…..

(a) The amount of water vapour in the air increases.
Ans: We feel the dampness or the humidity.

(b) Only one crop is grown repeatedly in the soil.
Ans: The fertility of the soil decreases.

Q.4: With whom should I pair up?

Column ‘A’	Column ‘B’
1. Air	(a) Excretion
2. Water	(b) Scattering of light
3. Soil	(c) Plasticity

Answer:

Column ‘A’	Column ‘B’
1. Air	(b) Scattering of light
2. Water	(a) Excretion
3. Soil	(c) Plasticity

Properties of Natural Resources – Questions Answers

Q.5: With whom should I pair up?

(a) Sandy soil has low capacity for holding water.
Answer: True

(b) Sea water is a bad conductor of electricity.
Answer: False. Sea water is a good conductor of electricity

(d) The pressure exerted by air is called atmospheric pressure.
Answer: True

Q. 6 : Explain the picture in your own words.

Answer:
• Diagram (a): Water is filled in the rock crack.
• Diagram (b): Water in the crack turns in to the ice due to decrease in temperature. When water turns in to ice the volume increases and it expands. Due to expansion of the water, the size of crack wider that the diagram (a).

Q.7: Write answers to the following questions in your own words.

Q. a : How is light scattered by the air?
Answer:
• Air is a mixture of some gases, dust particles, smoke and moisture.
• When rays of light hits on these minute dust particles, the particles spread the light in all the directions.
• This natural phenomenon is called scattering of light.

Q. b: Explain the various properties of water.
Answer: There are various properties of water as follows:
• It is a universal solvent.
• It does not have its own shape, it takes the shape of a container in which it is kept.
• It has a definite volume.
• It is a transparent liquid and it has no colour.
• It is a fluid substance because it can flow.
• It is tasteless and odourless.

Q. c : Why is the density of seawater is more than that of rainwater?
Answer:
• The density of seawater is more than that of rainwater because seawater contains dissolved salts and minerals.
• These extra substances add mass to the water, making it denser than rainwater.

Q. d: What is the importance of good soil structure?
Answer: The fertility of soil depends upon soil structure. So importance of good soil structure are as follows:
• Good soil structure helps plants grow better by providing the right balance of air, water, and nutrients.
• It allows water to drain properly, preventing plants from getting too much or too little water.
• Good soil structure helps hold the soil together, reducing erosion.

Q. e: What are the various uses of soil?
Answer: The uses of soil are as follows:
• Plant Growth: Soil provides nutrients and support for plants to grow.
• Habitat: Many animals and insects live in the soil.
• Water Filtration: Soil helps filter and clean water as it passes through.
• Agriculture: Soil is essential for farming and growing food crops.
• Plasticity: We can use it to make articles of a variety of shapes

Q. f: What is the need and importance of soil testing from the point of view of farmers?
Answer: Soil testing is important for farmers because
• It helps them understand the health and nutrients in their soil.
• It help farmers can know what kind of fertilizers to use and how much to use.
• This helps plants grow better and produce more food, use less chemicals.
• It helps farmers grow healthy crops and take care of their land.

Q. g. What is the importance of air in transmission of sound?
Answer: • Air is important in the transmission of sound because
• Sound waves travel through air to reach our ears.
• When sound generate it creates vibrations in the air.
• These vibrations travel through a medium and air is help for that.

Q. h: Why should a glass bottle completely filled with water never be kept in a freezer?
Answer: Due to anomalous behaviour of water, when you cool water below 4°C, the volume of the water increases.

Therefore when the glass bottle completely filled with water is kept in a freezer, water expands on cooling and its volume increases so glass bottle breaks.

To avoid this, completely filled bottle is never kept in a freezer.

— Properties of Natural Resources – Questions Answers – Complete solution

Additional Questions for your practice:

A) Fill in the blanks with the appropriate term.

Q. 1 : Atmospheric pressure is the …………… in all the directions.
Answer: same

Q. 2 : The level of …………… in the air is determined by its capacity to hold water vapour.
Answer: humidity

Q. 3. …………… is used to measure atmospheric pressure.
Answer: Barometer

Q. 4. …………… an effect of the difference in air pressure.
Answer: Wind

Q. 5. Air is a …………… of gases.
Answer: mixture

Q. 6. As we go higher the sea level and the atmospheric pressure …………….
Answer: decreases

Q. 7. When the temperature of air is low, its capacity to hold the vapour is …………….
Answer: less

Q. 8. : Air is useful as a …………… for the transmission of sound.
Answer: medium

Q. 9. Ice is …………… than water.
Answer: lighter

Q. 10. …………… is celebrated as World Soil Day.
Answer: 5th December

Q. 11. Under ordinary conditions atmospheric pressure at sea level is …………… Newtons per square meter.
Answer: 101400

Q. 12. …………… soil is easy to plough but less fertile.
Answer: Sandy

Q. 13. The space occupied by a substance is its …………… .
Answer: volume

Q. 14. The excess of water vapour during the night or dawn is transformed into ………….. .
Answer: dew

B) Identify true or false, if false correct and rewrite the statements.

Q.1 Terracotta soil is white in colour.
Answer: False. Terracotta soil is red in colour

Q.2. Rotation of crops decreases the fertility of the soil.
Answer: False. Rotation of crop increases the fertility of the soil.

Q.3. Clay soil has the maximum proportion of small particles.
Answer: True

Q.4. The density of substance is the inter-relation between the volume and mass of a substance.
Answer: True

Q.5. Silt soil is not as ploughable as sandy soil.
Answer: True

Q.6. Kerosene is a universal solvent.
Answer: False. Water is an universal solvent

Q.7. Multani soil is used to make statues and idols.
Answer: False. Shadu soil is used to make statues and idols

Q.8. Water is lighter than ice.
Answer: False. Ice is lighter than water

Q.9. The fertility of soil depends upon soil structure.
Answer: True

Q.10. The colour of soil near land surface is darker than the colour of the lower layers.
Answer: True

मराठी इयत्ता ४थी – सर्व धड्यांचे प्रश्न-उत्तर – All Lesson Question Answers

मराठी इयत्ता ४थी – सर्व धड्यांचे प्रश्न-उत्तर

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Properties of Natural Resources | Class 7 Science Chapter 3 – Perfect Question Answers