Maharashtra Board Class 5 EVS Part 1 Chapter 24 Substances Objects and Energy Solutions

5th Standard EVS 1 Lesson Number 24 Question Answer Substances, Objects And Energy Maharashtra Board

Std 5 EVS 1 Chapter 24 Question Answer

Question 1. What's the solution?
a. We need to make a sherbet quickly for some guests. But we only have sugar candy in the house.
Answer:
In simple words: To make sherbet quickly with sugar candy, you can crush the candy into a fine powder first, as smaller pieces dissolve faster in water.

🎯 Exam Tip: When asked for a solution, identify the core problem (slow dissolving) and propose a practical, simple method to overcome it (crushing to increase surface area).

Question b. We need to rub salt on a corncob but only salt crystals are available.
Answer: We can pound salt crystals. Either we can use mortar pestle or we can also crush the crystals of salt in a grinder. Such powdered salt can be easily applied on the corncob. This method makes the salt more effective for rubbing.
In simple words: To use salt crystals on a corncob, we can crush them into a powder using a mortar and pestle or a grinder, making them easier to apply.

🎯 Exam Tip: When asked about practical solutions, describe the steps clearly and mention the tools or methods used.

2. Use Your Brain Power!

Question a. Why do tablets of camphor decrease in size day by day ?
Answer: Tablets of Camphor are in solid state. Camphor has a property to turn into gaseous state directly from a solid state. Therefore, camphor decreases in size gradually. One can also notice the fragrance of camphor as it turns into vapour, which is a process called sublimation.
In simple words: Camphor tablets shrink because they change directly from a solid to a gas, a process called sublimation, releasing their smell as they do.

🎯 Exam Tip: Remember the term 'sublimation' when explaining why solids like camphor or dry ice disappear without melting.

Question b. How do we save fuel by using public transport ?
Answer: Each automobile vehicle needs fuel either in the form of petrol, diesel, or CNG. If all the people use a separate vehicle, the amount of fuel consumed would be much more. If many people start using public transport, fuel consumption would be reduced. A single bus or a train can carry many people and thus it can save lots of fuel, contributing to environmental sustainability.
In simple words: Using public transport saves fuel because one bus or train carries many people, reducing the number of individual cars on the road and overall fuel use.

🎯 Exam Tip: When discussing environmental benefits, always link actions like using public transport to broader impacts like reduced fuel consumption and pollution.

3. Answer The Following Questions.

Question a. When and why do clothes smell of naphthalene?
Answer:

Question b. In which states is water found in nature?
Answer: Water is found in all three states in nature, solid, liquid and gaseous state. Ice is the solid state of water. Water in lakes, sea etc. are in liquid state and steam or vapour is the gaseous state of water. Understanding these states helps us appreciate the diverse forms water takes on Earth.
In simple words: Water exists naturally as ice (solid), liquid water (like in rivers), and steam or vapor (gas).

🎯 Exam Tip: When asked about states of matter, always provide examples for each state to demonstrate your understanding.

Question c. What is the difference between the solid, liquid and gaseous states of a substance?
Answer: The differences in the solid, liquid and gaseous state of substances is given in the table below:
Solid State:
1. The solids have definite shape and volume.
2. The particles in solids are packed very close to each other. (Particles are tightly packed in a regular arrangement.)
3. The particles in solid cannot move away from each other.
Liquid State:
1. The liquids have no definite shape; it takes the shape of a container.
2. The distance between particles in the liquid is greater as compared to solid but less when compared to gases. (Particles are loosely packed and can move past each other.)
3. The particles can vibrate in their mean position.
Gaseous State:
1. The gases do not have definite shape or volume.
2. The distance between the particles is maximum in gases. (Particles are very far apart and move randomly.)
3. The particles can move away from each other.
In simple words: Solids have a fixed shape and volume with tightly packed particles, liquids have no fixed shape but fixed volume with loosely packed particles, and gases have no fixed shape or volume with very spread-out particles.

🎯 Exam Tip: When comparing states of matter, focus on particle arrangement, shape, and volume as key distinguishing features. Clearly listing these points helps score full marks.

Question d. What is meant by energy?
Answer: The capacity to do the work is called energy. This fundamental concept is crucial across all branches of science.
In simple words: Energy is simply the ability to do work or cause change.

🎯 Exam Tip: Remember the concise definition of energy: "the capacity to do work." This is a core concept that should be memorized.

Activities

Question 1. Make different kinds of articles from clay.
Answer: We can make various articles from clay such as pots, diyas, sculptures, decorative items, and even small models of animals or buildings. Working with clay is a wonderful way to express creativity and learn about traditional crafts.
In simple words: You can make many things from clay like pots, lamps, and small statues, which is a fun way to be creative.

🎯 Exam Tip: When asked about activities, think of common examples related to the material or skill mentioned and briefly describe them.

Question 2. Visit a wood workshop and observe the work being done there.
Answer: In a wood workshop, one can observe various processes like cutting wood with saws, shaping it with chisels and planes, sanding surfaces smooth, and assembling pieces to create furniture or other wooden objects. It's fascinating to see raw wood transformed into finished products.
In simple words: In a wood workshop, you would see people cutting, shaping, and joining wood to make things like furniture.

🎯 Exam Tip: For observational tasks, list specific actions and tools you would expect to see, showing a clear understanding of the environment.

Question 3. Obtain some information about the power generation plants in Maharashtra and present it in the classroom.
Answer: In Maharashtra, there are various types of power generation plants, including thermal power plants (using coal), hydroelectric power plants (using water), and increasingly, solar and wind power plants. Information to gather could include their locations, the type of energy source they use, and how they contribute to the state's electricity supply. This helps understand where our electricity comes from.
In simple words: Find out about different power plants in Maharashtra, like those using coal or water, where they are, and how they make electricity for us.

🎯 Exam Tip: When researching, focus on key facts like location, energy source, and impact, and organize your information clearly for presentation.

Environmental Studies Part 1 Standard 5th Solutions Chapter 24 Substances, Objects And Energy Additional Important Questions And Answers

Fill In The Blank With The Correct Answers From The Options Given Below:

Question 1. All substances we see around us are made up of very tiny .........
(a) dust
(b) particles
(c) mud
Answer: (b) particles
In simple words: Everything around us, even things that look solid, is actually made of extremely small pieces called particles.

🎯 Exam Tip: Remember that all matter is composed of tiny particles, a fundamental concept in science.

Question 2. ......... of particles of any substance must come together to form a particle that can be visible to our eyes.
(a) Lakhs
(b) Thousands
(c) Hundreds
Answer: (a) Lakhs
In simple words: Many, many tiny particles, like hundreds of thousands, have to join up before we can actually see them with our eyes.

🎯 Exam Tip: Understand the scale: individual particles are microscopic, and it takes a huge number of them to become visible.

Question 3. Naphthalene balls which are kept open are continuously converted to small particles in the ...... state.
(a) liquid
(b) solid
(c) gaseous
Answer: (c) gaseous
In simple words: Naphthalene balls change directly from solid to gas without becoming liquid, a process called sublimation.

🎯 Exam Tip: Remember that sublimation is the direct change from solid to gas, which is what happens with naphthalene balls.

Question 4. Different substances have different ............
(a) material
(b) properties
(c) code
Answer: (b) properties
In simple words: Every substance has its own unique characteristics, like color, smell, or how it reacts, which are called its properties.

🎯 Exam Tip: When describing substances, focus on their unique characteristics or 'properties' that distinguish them from others.

Question 5. ............ is required to do work.
(a) Energy
(b) Strength
(c) Health
Answer: (a) Energy
In simple words: To perform any action or task, whether big or small, you need energy.

🎯 Exam Tip: In physics, 'work' has a specific meaning related to force and displacement, and energy is always required to perform it.

Question 6. When something burns energy is released in the form of ............
(a) heat
(b) rain
(c) cold
Answer: (a) heat
In simple words: Burning is a chemical reaction that releases energy, most noticeably as heat and often light.

🎯 Exam Tip: Remember that combustion (burning) is an exothermic reaction, meaning it releases energy, primarily as heat.

Question 7. Energy in the form of motion is called ......... energy.
(a) Kinesthetic
(b) Kinetic
(c) Solar
Answer: (b) Kinetic
In simple words: Kinetic energy is the energy an object possesses due to its movement.

🎯 Exam Tip: Remember that 'kinetic' always relates to motion, while 'potential' relates to stored energy or position.

Question 8. Stores of ............ and ....... which are used as fuels, on earth are limited.
(a) mineral oil
(b) uranium
(c) coal
Answer: (a) mineral oil, (c) coal
In simple words: Mineral oil and coal are fossil fuels that took millions of years to form, meaning their supply on Earth is finite and cannot be quickly replaced.

🎯 Exam Tip: Differentiate between renewable (like solar, wind) and non-renewable (like fossil fuels, uranium) energy sources, noting that non-renewable sources are limited.

Question 9. Energy obtained from sun is called ............ energy
(a) lunar
(b) solar
(c) tidal
Answer: (b) solar
In simple words: Solar energy is the radiant light and heat from the Sun, harnessed using technologies like solar panels.

🎯 Exam Tip: Always associate 'solar' with the sun, just as 'lunar' is with the moon and 'tidal' with ocean tides, to correctly identify energy sources.

Question 10. Energy obtained by breaking the tiniest particle of a substance is called ...
(a) solar
(b) atomic
(c) kinetic
Answer: (b) atomic
In simple words: Atomic energy is released when the nucleus of an atom is split (fission) or combined (fusion), producing a vast amount of power.

🎯 Exam Tip: Atomic energy involves changes within the nucleus of an atom, releasing significant energy, unlike chemical reactions that involve electrons.

Question 11. Sunlight, wind and water are ............ sources of energy
Answer: Sunlight, wind and water are renewable sources of energy.
In simple words: These are natural resources that replenish themselves over time, making them sustainable for continuous use without depletion.

🎯 Exam Tip: Identify renewable sources of energy as those that can be naturally replaced or are inexhaustible, contrasting them with finite non-renewable sources.

Question 12. When iron or copper is made smooth with a file, we get ................ of iron or copper.
(a) particles
(b) soil
(c) saudust
Answer: (a) particles
In simple words: When you rub a file on iron or copper, tiny bits of the metal come off, which are called particles.

🎯 Exam Tip: Remember that filing always produces small particles, not soil or sawdust, as it's a metal-working process.

Question 13. Liquids are also made of small.......
(a) droplets
(b) particles
(c) dust
Answer: (b) particles
In simple words: Just like solids and gases, liquids are also made up of very tiny pieces called particles that are constantly moving.

🎯 Exam Tip: Understand that all matter, whether solid, liquid, or gas, is composed of tiny particles, which is a fundamental concept in science.

Question 14. ............... is found in three states – solid, liquid and gaseous.
(a) Mineral oil
(b) Carbon
(c) Water
Answer: (c) Water
In simple words: Water is unique because it can naturally exist as ice (solid), liquid water, and steam (gas) depending on the temperature.

🎯 Exam Tip: Water is a classic example of a substance that exists in all three states of matter, making it a common question in exams.

Question 15. In nature, every substance occurs in a............ state.
(a) special
(b) specific

Question 16. Aluminium and coal are is. .......... state.
(a) solid
(b) liquid
(c) gaseous
Answer: (a) solid
In simple words: Aluminium and coal are both materials that have a definite shape and volume, which are characteristics of solids.

🎯 Exam Tip: Remember the basic properties of solids, liquids, and gases to correctly identify the state of matter for common substances.

Question 17. Kerosene and petrol are in .......
(a) solid
(b) liquid
(c) gaseous
Answer: (b) liquid
In simple words: Kerosene and petrol are fuels that flow and take the shape of their container, which means they are liquids.

🎯 Exam Tip: Think about how substances behave at room temperature to determine their state of matter; liquids flow and have no fixed shape but a fixed volume.

Question 18. Nitrogen and Oxygen are in .............state.
(a) solid
(b) liquid
(c) gaseous
Answer: (c) gaseous
In simple words: Nitrogen and Oxygen are the main components of the air we breathe, and they spread out to fill any container, indicating they are gases.

🎯 Exam Tip: Recall that gases have no definite shape or volume and can be easily compressed, which is true for atmospheric gases like nitrogen and oxygen.

Question 19. The capacity of a body to do work is called
(a) work out
(b) energy
(c) exercise
Answer:
In simple words: The ability of anything to perform work, whether it's moving an object or generating heat, is fundamentally defined as energy.

🎯 Exam Tip: Always remember the fundamental definition of energy in physics: it is the capacity to do work. This is a core concept that appears frequently.

Question 20. When petrol or diesel burns in a motor vehicle, ............ gets released.
(a) fire
(b) fuel
(c) energy
Answer: (c) energy
In simple words: When petrol or diesel burns, it releases energy, which is then used to power the motor vehicle.

🎯 Exam Tip: Remember that the combustion of fuels converts chemical energy into heat and kinetic energy, which is the 'energy' released for motion.

Question 21. Machines can be run using ....................
(a) energy
(b) fuels
(c) water
Answer: (b) fuels
In simple words: Many machines require fuels, like petrol, diesel, or electricity, to operate and perform their functions.

🎯 Exam Tip: While machines use energy, fuels are the specific materials that provide this energy through processes like combustion or electrical conversion.

Question 22. Coal, diesel, CNG, LPG, petrol are all substances from which energy is obtained in form of
(a) heat
(b) rain
(c) cold
Answer: (a) heat
In simple words: When these substances burn, they produce heat, which is a form of energy that can be used for various purposes.

🎯 Exam Tip: These substances are common energy sources, and their primary energy output when consumed is thermal energy, or heat.

Question 23. When a person or vehicle moves, heat energy gets converted into .......
(a) electricity
(b) rain
(c) motion

Question 24. Electricity is also a form of .............
(a) machine
(b) energy
(c) heat
Answer: (b) energy
In simple words: Electricity is a type of energy that can be converted into other forms like light, heat, or mechanical energy to power devices.

🎯 Exam Tip: Remember that electricity is a fundamental form of energy, not a machine or just heat. Understanding its nature helps in many physics concepts.

Question 25. We use ............. to run the T.V.
(a) wires
(b) plugs
(c) electricity
Answer: (c) electricity
In simple words: A television needs electricity to power its internal components and display images and sound.

🎯 Exam Tip: While wires and plugs are used to connect the TV, electricity is the actual power source that makes it work. Focus on the direct energy input.

Question 26. In a solar cooker ............. energy is used.
(a) solar
(b) electricity
(c) L.P.G.
Answer: (a) solar
In simple words: A solar cooker uses energy from the sun, which is called solar energy, to heat and cook food without needing fuel or electricity.

🎯 Exam Tip: The name "solar cooker" directly indicates its energy source. Always link the device name to its primary energy input.

Question 27. Plants use....... to prepare their food.
(a) LPG
(b) induction
(c) sunlight
Answer: (c) sunlight
In simple words: Plants use sunlight, along with water and carbon dioxide, to make their own food through a process called photosynthesis.

🎯 Exam Tip: Photosynthesis is a key biological process where plants convert light energy into chemical energy. Sunlight is crucial for this process.

Question 28. When we burn substances like coal or mineral oil, the ............ energy, they contain is converted into heat energy.
(a) solar
(b) stored
(c) lunar
Answer: (b) stored
In simple words: Coal and oil hold energy that was stored long ago; when burned, this stored energy changes into heat.

🎯 Exam Tip: Remember that fossil fuels like coal and oil are sources of stored chemical energy, which is released as heat when combusted.

Question 29. Stores of coal and mineral oil on earth are
(a) unlimited
(b) limited
(c) plenty
Answer: (b) limited
In simple words: Coal and mineral oil are non-renewable resources, meaning there's only a certain amount of them available on Earth.

🎯 Exam Tip: Understand the difference between renewable and non-renewable resources; coal and oil are classic examples of limited, non-renewable resources.

Question 30. ............ batteries produce electricity using sunlight
(a) Water
(b) Solar
(c) Tidal
Answer: (b) Solar
In simple words: Solar batteries, also known as solar cells, convert energy from the sun's light directly into electrical power.

🎯 Exam Tip: When thinking about energy sources, associate "sunlight" directly with "solar" technology, as it's the most common and direct application.

Name The Following

Question 1. Any three substances found in solid state.
Answer: Iron, copper, aluminium, wood are common examples of substances found in a solid state, known for their fixed shape and volume.
In simple words: Solids are things that keep their shape, like iron, copper, aluminum, and wood.

🎯 Exam Tip: When asked for examples of states of matter, provide common, everyday items that clearly demonstrate the properties of that state.

Question 2. Three substances found in liquid state.
Answer:
In simple words: Liquids are substances that flow and take the shape of their container, like water, milk, or oil.

🎯 Exam Tip: To score full marks, list three distinct examples of liquids, such as water, milk, and oil, which are easily recognizable.

Question 3. Three substances found in gaseous state.
Answer: Naphthalene balls, iodine crystals. These substances undergo sublimation, turning directly from solid to gas.
In simple words: These are examples of things that turn straight into a gas from a solid without becoming liquid first.

🎯 Exam Tip: Remember that substances like naphthalene and iodine are unique because they sublimate, meaning they skip the liquid phase when changing from solid to gas.

Question 4. Substances which goes into gaseous state directly from solid state.
Answer: Naphthalene balls. This process is known as sublimation, a unique phase transition.
In simple words: Naphthalene balls turn directly into a gas from a solid, which is a special kind of change called sublimation.

🎯 Exam Tip: When asked about substances that directly convert from solid to gas, "sublimation" is the key term to use, and naphthalene is a classic example.

Question 5. Properties of substances.
Answer: Transparency, hardness, colour, smell, solubility in water. These characteristics help us identify and classify different materials.
In simple words: These are ways we can describe and tell apart different materials, like if they are clear, hard, or dissolve in water.

🎯 Exam Tip: When listing properties, try to include a variety of physical characteristics that are easily observable and measurable.

Question 6. Fuels used for running machines.
Answer: LPG, CNG, coal, diesel, petrol. These fuels release energy when burned, powering various engines and systems.
In simple words: These are different types of energy sources that machines use to work, like the gas in cars or coal for power plants.

🎯 Exam Tip: Remember to list both gaseous fuels (LPG, CNG) and solid/liquid fuels (coal, diesel, petrol) to show a comprehensive understanding of energy sources.

Question 7. Examples of kinetic energy.
Answer: Moving wind mill, sailing boats, running water, moving car etc. Kinetic energy is the energy an object possesses due to its motion.
In simple words: Kinetic energy is the energy things have when they are moving, like a spinning windmill or a car driving.

🎯 Exam Tip: Always associate kinetic energy with movement; any object or substance in motion is a good example.

Question 8. Forms of energy.
Answer: Sound, heat, light, electricity. Energy can transform from one form to another, but it is never truly lost.
In simple words: Energy can show up in different ways, like the warmth from a fire, the brightness of a lamp, or the power that runs electronics.

🎯 Exam Tip: When listing forms of energy, think about how energy manifests in everyday life, from what you hear and see to what powers your devices.

Question 9. Main source of energy used by us.
Answer: Electricity. The widespread use of electricity makes it a primary energy source for many daily activities.
In simple words: Electricity is the main energy we use for most things.

🎯 Exam Tip: When asked about the main source of energy, consider the most common and versatile form used in daily life.

Question 10. Energy sources which do not cause pollution
Answer: Wind energy, solar energy. These renewable sources are crucial for a sustainable future.
In simple words: Wind and solar power are clean energy sources that don't pollute.

🎯 Exam Tip: Remember to list common renewable energy sources when asked about non-polluting options.

Answer In One Sentence:

Question 1. What are all subtances made up of?
Answer: All substances are made up of fine particles. These tiny particles are the building blocks of everything around us.
In simple words: Everything is made of tiny particles.

🎯 Exam Tip: The key concept here is that matter is composed of particles; stating "fine particles" is sufficient for a concise answer.

Question 2. Why do naphthalene balls grow smaller in size and gradually disappear?
Answer: Naphthalene when left open continuously gets converted into small gaseous particles, so, as these particles leave the naphthalene balls, they grow smaller is size and slowly disappear. This process is known as sublimation, where a solid turns directly into a gas.
In simple words: Naphthalene balls turn directly into gas particles and float away, making the balls shrink and disappear.

🎯 Exam Tip: The core reason is the conversion of solid naphthalene directly into gas (sublimation), causing the particles to leave the ball.

Question 3. Which substance is found in all three states?
Answer: Water is found in all three states – solid, liquid and gaseous. It is unique in its ability to exist naturally in all three forms on Earth.
In simple words: Water can be found as a solid (ice), liquid (water), and gas (steam).

🎯 Exam Tip: Water is the most common example of a substance found in all three states (ice, water, steam); remember these forms.

Question 4. What are the different properties of substance?
Answer: Different substances have different properties, like hardness, transparency, colour, smell, solubility in water etc. These properties help us identify and distinguish between various materials.
In simple words: Substances have different traits like how hard they are, their color, smell, and if they dissolve in water.

🎯 Exam Tip: When listing properties, include a variety of physical characteristics such as hardness, appearance, and how it interacts with other substances.

Question 5. What is 'energy?
Answer: The capacity of a body to do work is called energy. This fundamental concept explains how work is performed.
In simple words: Energy is simply the ability of something to do work or cause movement.

🎯 Exam Tip: Remember the definition of energy as the capacity to do work; it's a fundamental concept in physics.

Question 6. How is energy released?
Answer: When petrol or diesel burns in a motor vehicle, energy gets released. This chemical process converts stored energy into kinetic energy and heat.
In simple words: Energy is released when fuels like petrol or diesel burn, like in a car engine, making it move.

🎯 Exam Tip: Think of common examples like burning fuel or food digestion to explain how energy is released from stored forms.

Question 7. Name some substance from which energy is obtained.
Answer: Coal, diesel, CNG, LPG, petrol are all substances from which energy is obtained. These are commonly used fossil fuels.
In simple words: We get energy from fuels like coal, diesel, CNG, LPG, and petrol, which we use for many things.

🎯 Exam Tip: List common fossil fuels and gases as examples of energy sources; these are often referred to as conventional energy sources.

Question 8. What is Kinetic energy?
Answer: Energy in the form of motion is called Kinetic energy. Any moving object possesses kinetic energy.
In simple words: Kinetic energy is the energy an object has because it is moving.

🎯 Exam Tip: Associate 'kinetic' directly with 'motion' or 'movement' for a quick recall of its definition.

Question 9. Why should we find alternate sources of energy?
Answer: Stores of coal and mineral oil on earth are very limited and fast depleting therefore we must find alternate sources of energy. Relying solely on these finite resources is unsustainable.
In simple words: We need new energy sources because our current ones, like coal and oil, are running out quickly.

🎯 Exam Tip: Emphasize the 'limited' and 'depleting' nature of fossil fuels as the main reason for seeking alternatives like solar or wind energy.

Question 10. What are solar batteries?
Answer: Batteries which produce electricity using sunlight are called solar batteries. They convert solar energy directly into electrical energy.
In simple words: Solar batteries are special batteries that make electricity by capturing energy from the sun.

🎯 Exam Tip: Define solar batteries by their function (produce electricity) and their energy source (sunlight).

Question 11. Why should we make a habit of using minimum amount of electricity?
Answer: In any method of electricity generation, resources from the environment have to be used. Hence, we should make a habit to conserve electricity, ensuring a sustainable future.
In simple words: We should use less electricity because making it uses up natural resources, so saving electricity helps protect our environment.

🎯 Exam Tip: When answering questions about conservation, always mention the impact on natural resources and sustainability to score well.

Use Your Brain Power!

Question 1. What uses of heat energy do we see in our daily life?
Answer: We use heat energy to cook food, to heat water, to press our clothes, to keep us warm during cold winters in areas where temperature is very low, etc. Heat energy is essential for many daily activities.
In simple words: We use heat every day for cooking, warming water, ironing clothes, and staying warm in cold weather.

🎯 Exam Tip: When listing uses of energy, try to provide a variety of examples from different aspects of daily life to show comprehensive understanding.

Question 2. Why do tablets of camphor decrease in size day by day?
Answer: Camphor particles present in the tablets escape by getting converted directly to gaseous state. Therefore the tablets of camphor decrease in size day by day. This process is known as sublimation.
In simple words: Camphor tablets shrink because the solid camphor turns directly into a gas and escapes into the air over time.

🎯 Exam Tip: For questions about physical changes, remember to use scientific terms like "sublimation" if applicable, and explain the process clearly.

Question 3. How do we save fuel by using public transport?
Answer: If people drive car instead of using public transport while going to work, more fuel will be burnt, as each car will burn the fuel to release energy and work. However if public transport is used, we need to use fuel, only for one transport vehicle. Hence it will save a lot of fuel if people use the public transport, reducing overall consumption and pollution.
In simple words: Public transport saves fuel because one bus or train carries many people, using much less fuel than if each person drove their own car.

🎯 Exam Tip: When discussing environmental benefits, always compare the "before" and "after" scenarios to highlight the positive impact of the suggested action.

Answer The Following Questions:

Question 1. What is meant by energy? Name the sources of energy
Answer: The capacity of a body to do work is called energy. Energy is obtained by burning fuel, and it is fundamental to all physical processes.
In simple words: Energy is the ability to do work. We get energy from things like burning fuel.

🎯 Exam Tip: Always start definitions with a clear, concise statement and then provide relevant examples or sources to elaborate.

Question 2. What is the original source of energy for the electricity produced at a thermal power station? How is electricity generated?
Answer: In a thermal power station coal is the original source of energy. Here coal is burnt to release heat. The heat generated is utilised to convert water to steam. Then steam is used to rotate the turbines. As the turbine rotates electricity is produced. This process efficiently converts chemical energy into electrical energy.
In simple words: Thermal power stations burn coal to make heat, which turns water into steam. This steam then spins turbines to create electricity.

🎯 Exam Tip: When explaining energy generation, always mention the primary fuel source, the energy conversion steps (e.g., heat to steam, steam to mechanical, mechanical to electrical), and the final output.

Can You Tell?

1. Write a few lines on the black board with a chalk. Now observe the chalk.

Question a. What change do you see in the chalk?
Answer: The chalk becomes smaller in size, after writing. This is due to the transfer of chalk particles onto the board.
In simple words: When you write, tiny bits of chalk rub off, making the chalk stick shorter.

🎯 Exam Tip: For observation-based questions, clearly state the observed change and, if possible, a simple reason for it.

Question b. Why did the chalk become smaller in size after writing on the board?
Answer: When we wrote on the board the pieces of chalk stick to board, therefore the chalk became smaller in size. The friction between the chalk and the board causes small particles to detach.
In simple words: The chalk gets smaller because tiny pieces break off and stick to the board as you write.

🎯 Exam Tip: Always link the observed phenomenon to a scientific principle, like friction or material transfer, even in simple terms.

2. Wipe the board with a duster and then tap the duster against the table.

Question a. What do you see?
Answer: A fine white particles of chalk fell of the duster when we tapped it against the table. These particles are the remnants of the chalk that was transferred to the board.
In simple words: When you tap the duster, you see tiny white chalk dust falling off.

🎯 Exam Tip: Describe observations precisely, noting the color, texture, and action (e.g., "fine white particles fell").

Question b. From where did these white particles come?
Answer: When we rubbed the board, the chalk particles from the board stuck to the duster and when we tapped the duster these chalk particles fell. The chalk particles are very fine and easily detach from the duster.
In simple words: The white particles were chalk dust that came off the board when rubbed and then fell from the duster when tapped.

🎯 Exam Tip: When explaining a simple observation, describe the sequence of events clearly and concisely.

Question c. If there is a sudden shower, we take shelter under a roof on the road side. Even though the rain does not fall on us directly we get wet to some extent why?
Answer: The raindrops slow down the roof and fall on the ground. They break into fine droplets when they fall and bounce off the ground. These droplets make us wet. Hence though the rain does not fall on us directly we get wet to some extent. This phenomenon is due to the splash and spray of water.
In simple words: Even under a roof, you get wet because raindrops hit the ground, splash into tiny droplets, and these tiny droplets then spray onto you.

🎯 Exam Tip: When explaining natural phenomena, focus on the physical process involved, like splashing and fine droplets.

Question d. Asmita went to buy an earthen pot. There she saw many things kept for sale. How did she identify what she needed? From what substance had the potter made all the things?
Answer: Asmita identified the things kept from their shape and colour. The potter had made all the things using clay. People often recognize objects by their distinct visual characteristics.
In simple words: Asmita knew what she wanted by looking at the shape and color of the items, and everything was made from clay.

🎯 Exam Tip: For questions about identification, mention key sensory attributes like shape, color, or texture.

Question e. What is the difference between a substance and an object?
Answer: Difference between substance and object is given below:

🎯 Exam Tip: When asked for differences, present them in a clear, comparative table format to score full marks.

3. Wood, aluminium, coal, iron etc are examples of substances.

3. Table, chair, flower pots, lamp etc. are examples of objects.

Question f. There is a car. Its tank is full of fuel, but it does not move. Why is that?
Answer: The energy has to be released from the fuel to make the car move. The energy is released when the petrol burns. The petrol starts burning only after we turn on the car engine. Since the engine is not on, the car does not move even when its tank is full of fuel. This process highlights the importance of an ignition source to convert potential energy into kinetic energy.
In simple words: A car needs its engine turned on to burn fuel and create the energy needed to move, even if the tank is full.

🎯 Exam Tip: When explaining why a car doesn't move, focus on the need for the engine to be 'on' to initiate fuel combustion and energy release.

Question g. When we have run a long distance, we feel tired. We have to stop. Why is that?
Answer: We need energy to run. Hence when we run a long distance, the food present in the body is continuously burn to release energy. This energy is used to do the work of running. After running a long distance the food gets exhausted and the energy released decreases and therefore we feel tired and we stop. Our bodies require a constant supply of energy, and prolonged physical activity depletes these reserves.
In simple words: We get tired after running because our body uses up all the energy from the food we've eaten, and without more energy, we can't continue.

🎯 Exam Tip: Explain the link between energy, food, and physical activity, emphasizing that exhaustion occurs when energy reserves are depleted.

Glossary

1. fossil fuel – fuel formed in the earth o from plant or animal remains
2. exhaustible – the resources which can not be renewed or recycled
3. depleting - reduction in quantity
4. corncob – core of Indian com.

Class 5 Environmental Studies Questions And Answers