Test: Air, Water And Weather - 2 - Class 5 MCQ

Lemon seed

Explanation: When Ramesh added sugar and salt to the water, they dissolved in it. When he squeezed the lemon juice into the water, the juice also mixed with the water. After stirring, the sugar, salt, and lemon juice were all dissolved in the water. When he filtered the mixture with a strainer, only the solid particles like lemon seeds and pulp would be left behind, as the dissolved sugar, salt, and lemon juice would pass through the strainer along with the water.

The substance that will not dissolve in water is:
Answer: D. None of these
Explanation:
- Water is a universal solvent, meaning it has the ability to dissolve many substances.
- However, not all substances are soluble in water.
- Let's examine the options given:
A. Sugar:
- Sugar is a soluble substance.
- It dissolves easily in water, forming a sweet solution.
B. Salt:
- Salt (sodium chloride) is also a soluble substance.
- It dissolves readily in water, forming a salty solution.
C. Baking soda:
- Baking soda (sodium bicarbonate) is also soluble in water.
- It readily dissolves, forming a slightly alkaline solution.
D. None of these:
- The correct answer is D because all three substances mentioned (sugar, salt, and baking soda) are soluble in water.
- Therefore, none of the given options will not dissolve in water.
In summary, sugar, salt, and baking soda are all soluble in water, so the correct answer is D. None of these will not dissolve in water.

Explanation:
When we go up in the sky, the atmospheric pressure decreases. This is because the atmosphere becomes less dense as we move higher in altitude. The air molecules are more spread out, resulting in lower pressure.
Here is a detailed explanation of why atmospheric pressure decreases as we go up in the sky:
1. Understanding Atmospheric Pressure:
Atmospheric pressure is the force exerted by the weight of the air above a given point. It is caused by the gravitational attraction of the Earth on the air molecules in the atmosphere. The pressure decreases with increasing altitude.
2. Relationship Between Altitude and Atmospheric Pressure:
As we move higher in the sky, the number of air molecules above us decreases. This means there are fewer air molecules exerting a force on a given area, resulting in a decrease in atmospheric pressure.
3. Decrease in Density:
As we go higher in the sky, the density of the air decreases. This is because the air molecules become more spread out. With fewer air molecules per unit volume, the pressure exerted by the air decreases.
4. Barometric Pressure:
Barometric pressure is a measure of atmospheric pressure at a specific location and time. It is often measured using a barometer. As we ascend in altitude, the barometric pressure decreases.
5. Effects on Human Body:
The decrease in atmospheric pressure with increasing altitude can have physiological effects on the human body. At high altitudes, the lower atmospheric pressure can lead to decreased oxygen levels, which can result in altitude sickness.
To summarize, when we go up in the sky, the atmospheric pressure decreases. This is because the air becomes less dense and there are fewer air molecules exerting a force on a given area.

a) The lithosphere is the upper part of the earth. It includes the crust and the solid portion of the mantle. Lithosphere interacts with atmosphere, hydrosphere, and biosphere and produces the pedosphere (the soil with its biotic and abiotic components). The lithosphere contains rocks, minerals, and soils.
b) The ionosphere is a layer of plasma formed by the ionization of atomic oxygen and nitrogen by highly energetic ultraviolet and x-ray solar radiation. The Ionosphere extends from the middle of the mesosphere up to the magnetosphere.
c) The atmosphere of Earth is the layer of gases, commonly known as air, retained by Earth's gravity, surrounding the planet Earth and forming its planetary atmosphere. 
d) The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. 

The part of earth that contains water is called the Hydrosphere.
The hydrosphere is the layer of Earth that consists of water, including oceans, seas, lakes, rivers, groundwater, and even water vapor in the atmosphere. It plays a crucial role in supporting life and influencing various natural processes on Earth.
Key points about the hydrosphere:
- The hydrosphere covers approximately 71% of the Earth's surface.
- It includes all forms of water, whether it is in liquid, solid (ice), or gaseous (water vapor) state.
- Oceans are the largest bodies of water in the hydrosphere, covering about 97% of the Earth's water.
- The hydrosphere interacts with other Earth spheres such as the atmosphere and lithosphere, influencing weather patterns, erosion, and the distribution of nutrients.
- Water is constantly cycling through the hydrosphere in a process called the water cycle, which includes evaporation, condensation, precipitation, and runoff.
- The hydrosphere is essential for supporting and sustaining life on Earth, providing habitats for various organisms and serving as a source of freshwater for human consumption and agriculture.
In conclusion, the hydrosphere is the part of the Earth that contains water, encompassing all the water bodies on Earth, including oceans, lakes, rivers, and groundwater. It is a vital component of the Earth's system, influencing climate, weather patterns, and supporting various forms of life.

Atmosphere is the part of earth which consists of:
The atmosphere is the layer of gases that surrounds the Earth. It is composed of several components, including:
Air:
- The main component of the atmosphere is air, which is a mixture of gases such as nitrogen (78%), oxygen (21%), and small amounts of other gases like carbon dioxide, argon, and water vapor.
Water:
- The atmosphere also contains water vapor, which is the gaseous form of water. It is present in varying amounts, depending on factors such as temperature and location. Water vapor plays a crucial role in the formation of clouds and precipitation.
Land:
- While the atmosphere does not directly consist of land, it interacts with the Earth's surface through processes such as weathering, erosion, and deposition. These processes are influenced by atmospheric conditions and contribute to the overall dynamics of the Earth system.
All of these:
- The correct answer is option D: All of these. The atmosphere consists of air, water vapor, and also interacts with the land. It is a complex system that plays a vital role in supporting life on Earth, regulating climate, and protecting the planet from harmful radiation.
In summary, the atmosphere is composed of air, water vapor, and indirectly interacts with the land. It is a crucial component of the Earth system and plays a significant role in maintaining the planet's habitability.

Water is known as the universal solvent because:
- Dissolving Ability: Water has the ability to dissolve a wide variety of substances, earning it the title of the universal solvent. This is due to its unique molecular structure and polarity. The water molecule consists of two hydrogen atoms bonded to one oxygen atom, resulting in a bent shape with a slightly positive charge on the hydrogen atoms and a slightly negative charge on the oxygen atom. This polarity allows water molecules to attract and surround other charged or polar molecules, breaking them apart and forming a solution.
- Hydration: Water plays a crucial role in many chemical reactions and biological processes by acting as a medium for hydration. It can dissolve ions and polar molecules, facilitating their movement and participation in metabolic reactions. For example, in the human body, water acts as a solvent for nutrients, enzymes, and waste products, allowing them to be transported and transformed within cells.
- Versatility: Water's ability to dissolve a wide range of substances makes it versatile in various applications. It is commonly used as a solvent in industries such as pharmaceuticals, agriculture, and manufacturing. Water is also essential for cleaning purposes as it can dissolve dirt, stains, and other impurities, making it an effective cleaning agent.
- Environmental Significance: Water's ability to dissolve substances is crucial for the natural environment. It aids in weathering and erosion processes by dissolving minerals and carrying them away. Additionally, water's solvent properties enable it to transport nutrients and minerals within ecosystems, ensuring the survival and growth of plants and animals.
In conclusion, water is known as the universal solvent because of its exceptional ability to dissolve a wide variety of substances, its role in hydration and metabolic processes, its versatility in different industries, and its environmental significance.

The amount of water vapour in the air is called humidity.

Explanation:

• Humidity refers to the amount of water vapor present in the air.


• It is a measure of the air's moisture content.


• Humidity is typically expressed as a percentage and represents the relative amount of moisture in the air compared to the maximum amount it could hold at a given temperature.


• High humidity indicates that the air is saturated with moisture, while low humidity means that the air is relatively dry.


• Humidity plays a significant role in weather patterns, as it affects cloud formation, precipitation, and the overall comfort levels for humans and other living organisms.


• Measuring humidity is essential for various applications, including meteorology, agriculture, and indoor climate control.

In summary, the correct answer is C: Humidity. It is the term used to describe the amount of water vapor present in the air.

Statement (i): Air has no mass
- This statement is false.
- Air is composed of various gases, including nitrogen, oxygen, carbon dioxide, and trace amounts of other gases.
- Each of these gases has mass, and therefore, air as a whole has mass.
- The mass of air can be measured using a balance or by calculating the mass of a given volume of air.
Statement (ii): Air is needed for burning
- This statement is true.
- Burning requires oxygen, which is a component of air.
- Oxygen supports combustion by reacting with the fuel, releasing energy in the form of heat and light.
- Without air (specifically oxygen), burning cannot occur.
Statement (iii): Air exerts pressure from all sides and on everything
- This statement is true.
- Air molecules are constantly in motion and collide with surfaces, exerting pressure.
- The pressure exerted by air is known as atmospheric pressure.
- Atmospheric pressure is exerted in all directions, including upwards, downwards, and sideways.
- This pressure is responsible for various phenomena, such as wind, the functioning of barometers, and the ability to suck liquids through a straw.
Therefore, the correct answer is (ii) and (iii) (Option C).

Water Cycle Components:
The water cycle is a continuous process that involves the movement of water on, above, and below the Earth's surface. It includes several components, and two of them are:
1. Evaporation:
Evaporation is the process by which water changes from a liquid state to a gaseous state. It occurs when heat energy from the sun causes the water molecules to move faster and escape from the surface of bodies of water, such as oceans, lakes, and rivers. The water vapor rises into the atmosphere.
2. Condensation:
Condensation is the process by which water vapor in the atmosphere cools and changes back into liquid water. It occurs when the air becomes cooler, causing the water vapor to lose heat energy and form tiny water droplets or ice crystals. These droplets or crystals then come together to form clouds.
Conclusion:
Both evaporation and condensation are essential components of the water cycle. Evaporation allows water to enter the atmosphere as vapor, while condensation forms clouds and eventually leads to precipitation, completing the cycle.

Answer:

The example that demonstrates the pressure exerted by air is the "sucking up of water using a straw."

Explanation:

Here is a detailed explanation of why the sucking up of water using a straw demonstrates the pressure exerted by air:

• Air Pressure: Air exerts pressure on objects in its surroundings.


• Vacuum Creation: When you suck up water using a straw, you create a vacuum inside the straw.


• Pressure Difference: The pressure inside the straw becomes lower than the atmospheric pressure outside.


• Water Movement: Due to the pressure difference, the atmospheric pressure pushes the water up the straw and into your mouth.


• Observation: This demonstrates that air pressure can cause the movement of fluids, in this case, water.

It is important to note that the other examples mentioned (swimming in the ocean, rain falling on the ground, and flowing of air through tree leaves) do not directly demonstrate air pressure. While these examples involve air and its interactions, they do not specifically showcase the concept of air pressure.

Answer:
The correct representation of the composition of air is given by option D. Let's break down the composition of air and analyze each option:
Option A:
- P represents Nitrogen, but it is incorrectly shown as the most abundant gas in the air.
- Q represents Oxygen, but it is shown as the least abundant gas, which is incorrect.
- R represents an inert gas, which is not present in the composition of air.
- S represents Carbon dioxide, but it is shown as the second most abundant gas, which is incorrect.
Option B:
- P represents Nitrogen, but it is shown as the least abundant gas, which is incorrect.
- Q represents Oxygen, but it is shown as the most abundant gas, which is incorrect.
- R represents an inert gas, which is not present in the composition of air.
- S represents Carbon dioxide, but it is shown as the second most abundant gas, which is incorrect.
Option C:
- P represents Nitrogen, but it is shown as the least abundant gas, which is incorrect.
- Q represents Oxygen, but it is shown as the most abundant gas, which is incorrect.
- R represents an inert gas, which is not present in the composition of air.
- S represents Carbon dioxide, but it is shown as the second most abundant gas, which is incorrect.
Option D:
- P represents Nitrogen, and it is correctly shown as the most abundant gas in the air.
- Q represents Oxygen, and it is correctly shown as the second most abundant gas.
- R represents an inert gas, which is not present in the composition of air.
- S represents Carbon dioxide, and it is correctly shown as a minor component of air.
Therefore, option D is the correct representation of the composition of air.

Air pressure is the weight of a column of air pushing down on an area. While we cannot feel it, the air is heavy! The weight of the air pushing down on all objects on Earth is the same as the combined weight of three cars! The reason we don’t feel this extreme weight is that the molecules in air push evenly in all directions – up, down, sideways, diagonally. In this experiment, the air pushing up from underneath the paper is strong enough to overcome the weight of the water pushing down on the paper. Because of the air pressure pushing up on the card, the card will stay on the glass and the water will not spill out.

To understand what will happen when a block of wood is dropped in saline water, we need to consider the concept of buoyancy and the density of the water.
1. Buoyancy:
- Buoyancy is the upward force exerted by a fluid on an object submerged in it.
- It depends on the density of the fluid and the volume of the object.
2. Density:
- Density is the mass per unit volume of a substance.
- Freshwater has a lower density compared to saline water because of the dissolved salts in the latter.
Now let's analyze the options given:
A: Settle down at the bottom:
- This option is incorrect because the block of wood is less dense than water (both freshwater and saline water).
- The buoyant force will always be greater than the weight of the block, causing it to float.
B: Will be at the same level:
- This option is also incorrect because the block of wood will float due to its lower density.
- It will not remain at the same level as the water.
C: Float at a higher level:
- This option is correct.
- The block of wood will float at a higher level in saline water compared to freshwater.
- Saline water has a higher density than freshwater, so the block will displace a smaller volume of water to achieve buoyancy.
- As a result, the block will float higher in the saline water.
D: None of these:
- This option is incorrect because option C is the correct answer.
In conclusion, when a block of wood is dropped in saline water, it will float at a higher level compared to when it is dropped in freshwater.