Ch 1Measurements
5-Mark Questions
The distance between the two places is 43.65 km. convert it into meter and cm.
(a) Convert km into metre 1 km = 1000m ∴ 43.65 km = 43.65 × 1000 = 43650.00 = 43650 = 43650 m. (b) Convert km into cm. 1 km = 1000 m 1 m = 100 cm 1 km = 1000 × 100 cm 1 km = 100000 cm ∴ 43.65 km = 43.65 × 100000 = 4365000.00 = 4365000 cm.
What are the rules to be followed to make an accurate measurement with scale?
To make an accurate measurement with a scale, several important rules must be followed. First, always ensure that the object being measured is placed parallel to the scale so that it aligns properly with the markings. Second, start the measurement from the zero mark of the scale rather than from the edge, as this ensures accuracy and avoids errors. Third, take care to read the correct submultiple or division on the scale, as misreading can lead to significant errors. …
2-Mark Questions
We can say that mass an object is 126 kg Length of one’s chest can be measured by using metre scale. Ten millimetres makes one centimetre. A hand span is a reliable measure of length. The SI system of units is accepted everywhere in the world.
False. Mass is a measure of the amount of matter in an object, and it is measured in kilograms (kg) or grams (g). While the statement mentions 126 kg, it incorrectly associates it with the length of one's chest. False. The length of one's chest is typically measured using a measuring tape or a flexible ruler, not a metre scale, which is designed for longer distances. True. Ten millimetres are indeed equivalent to one centimetre (1 cm = 10 mm). False. A hand span is a traditional unit of length but is not considered a reliable measure because it varies from person to person. True. …
Sugar: Beam Balance, Lime Juice?
Sugar is measured using a beam balance to determine its mass or weight. Lime juice is measured using a graduated cylinder because it is a liquid and volume measurement is appropriate. The height of a person is measured in centimetres (cm). The length of a sharpened pencil lead is measured in millimetres (mm) because of its small size. Milk, being a liquid, is measured by volume using a graduated cylinder or measuring cup. Vegetables are typically measured by their weight or mass using a beam balance or weighing scale. …
1 Metre, 1 Centimetre, 1 Kilometre, and 1 Millimetre.
In order from smallest to largest, the units of length are arranged as follows: 1 millimetre, 1 centimetre, 1 metre, and 1 kilometre. A millimetre is the smallest unit among these, followed by the centimetre which is 10 times larger than a millimetre. A metre is 100 times larger than a centimetre, and a kilometre is 1000 times larger than a metre. This arrangement helps us understand the relative sizes of different length measurements used in various contexts.
1-Mark Questions (MCQ)
The girth of a tree can be measured by
(d) Measuring tape.
Ch 2Force and Motion
5-Mark Questions
The rotation of the earth is a periodic motion. Justify.
The rotation of the Earth is a periodic motion because it satisfies the definition of periodic motion, which is motion that repeats itself after a fixed interval of time. The Earth completes one full rotation on its axis in exactly 24 hours, which is a fixed and constant time period. After every 24 hours, the Earth returns to the same rotational position relative to the sun, and this rotation repeats continuously in the same manner. Since the Earth's rotation repeats at regular and equal intervals of time with a fixed period of 24 hours, it is classified as a periodic motion. …
Differentiate between rotational and curvilinear motion
Rotational motion and curvilinear motion are two distinct types of motion that differ in their paths and reference points. In rotational motion, a body moves along a circular path around a fixed axis without changing its position relative to that axis. The body spins or rotates about its own fixed center or axis, and every point on the body maintains a constant distance from the axis of rotation. A spinning top is a classic example of rotational motion, where the top rotates about its vertical axis while remaining in the same location. …
2-Mark Questions
To and fro motion is called oscillatory motion. Vibratory motion and rotatory motion are periodic motions. Vehicles moving with varying speeds are said to be in uniform motion. Robots will replace human in future.
The first statement is true because to and fro motion, where an object moves back and forth along the same path repeatedly, is indeed called oscillatory motion. The second statement is true because vibratory motion, which involves rapid back and forth movements, and rotatory motion, which involves spinning around an axis, are both examples of periodic motions that repeat at regular intervals. The third statement is non-uniform motion because vehicles moving with varying speeds do not travel equal distances in equal intervals of time, which is the definition of uniform motion. …
Complete the data of the table given below with the idea of uniform speed.
The force which acts on an object without Physical contact with it.
A non-contact force is a force that acts on an object without requiring any physical contact between the object and the source of the force. Examples of non-contact forces include gravitational force, which pulls objects toward the Earth without touching them, magnetic force, which attracts or repels magnetic materials from a distance, and electrostatic force, which acts between charged objects without them touching each other. These forces operate through fields that extend through space around the source.
1-Mark Questions (MCQ)
Unit of speed is
d. m/s
Ch 3Matter Around Us
5-Mark Questions
Give the main difference between a pure substance and an impure substance.
A pure substance and an impure substance differ in their composition and the methods used to separate them. A pure substance is made up of only one kind of particle or component. It has a fixed composition and definite properties such as melting point, boiling point, and density that remain constant. Pure substances cannot be separated into simpler components by physical means such as filtration, sedimentation, or decantation. Examples of pure substances include distilled water, pure salt, and pure iron. …
Why do gases not have fixed shape?
Gases do not have a fixed shape because the forces of attraction between the gaseous particles are extremely weak. Due to these weak intermolecular forces, the particles of a gas are far apart from each other and move randomly in all directions with high speed. This random motion and weak attraction between particles mean that gases cannot maintain a fixed shape on their own. Instead, gases can flow freely and easily move from one place to another. When a gas is placed in a container, it expands to fill the entire volume of that container and takes the shape of the container. …
2-Mark Questions
Define the term matter.
Matter is defined as anything that has mass and occupies space or volume. Matter exists in three main states: solid, liquid, and gas. In the solid state, matter has a fixed shape and fixed volume with particles tightly packed together. In the liquid state, matter has a fixed volume but no fixed shape, taking the shape of its container. In the gaseous state, matter has neither fixed shape nor fixed volume, and its particles are widely spread apart. All physical objects and substances around us are made of matter.
How can husk or fine dust particles be separated from rice before cooking?
Before cooking, husk or fine dust particles in rice are separated by winnowing, not sedimentation. Winnowing is a process in which the mixture is exposed to wind or air current. The lighter impurities like husk and dust particles are blown away by the wind due to their lower density, while the heavier rice grains fall straight down and are collected. This method is effective because it takes advantage of the difference in weight between the rice grains and the lighter impurities. …
Why do we separate mixtures?
We separate mixtures because a mixture is an impure substance that contains particles of two or more different substances mixed together. By separating mixtures, we can obtain the pure components of the mixture, which can then be used for specific purposes. Separation of mixtures is important in many practical applications, such as obtaining pure drinking water from salt water through distillation, separating different components of crude oil through fractional distillation, and removing impurities from food items before cooking. …
1-Mark Questions (MCQ)
………. is not made of matter
(a) light ray
Ch 4The Living World of Plants
5-Mark Questions
Plants can live without water. All plants have chlorophyll. Plants have three parts; the root, the stem, and the leaves. Mountain is an example of a freshwater habitat. Root is modified into spines. Green plants need sunlight.
The first statement is false because plants cannot live without water. Water is essential for plants as it is required for various vital functions including photosynthesis, nutrient transport, maintaining cell turgidity, and overall growth and development. The second statement is false because not all plants have chlorophyll. Only green plants contain chlorophyll, which is the pigment responsible for photosynthesis. Non-green plants such as fungi and some parasitic plants do not have chlorophyll. …
Compare the taproot and fibrous root systems.
Taproot and fibrous root systems are two different types of root systems found in plants, each with distinct characteristics. The taproot system consists of a single main root that grows vertically downward into the soil, with smaller lateral roots branching off from it. This system is typically found in dicotyledonous plants such as mango, neem, and bean. The taproot can penetrate deep into the soil to access water and minerals from greater depths. In contrast, the fibrous root system consists of a cluster of many roots of similar size and thickness that spread out horizontally in the soil. …
2-Mark Questions
Leaf – Stem – Root – Flower
The correct order of plant parts from bottom to top is root, stem, leaf, and flower. The root is the underground part that absorbs water and minerals. The stem grows upward and supports the leaves and flowers. Leaves are attached to the stem and carry out photosynthesis. Flowers are the reproductive organs that develop at the top of the plant. This hierarchical arrangement shows how different plant organs are organized in a typical flowering plant.
Transpiration – Conduction – Absorption – Fixation.
The correct sequence of these plant processes in order is fixation, absorption, conduction, and transpiration. Fixation refers to the process where plants fix carbon dioxide during photosynthesis. Absorption is when roots take in water and mineral nutrients from the soil. Conduction is the transport of water, minerals, and food through the vascular tissues of the plant. Transpiration is the loss of water vapor from the leaves and other aerial parts of the plant into the atmosphere. This sequence represents the flow of materials and energy through a plant.
Classify plants on the basis of their habitat.
Plants can be classified into two main categories based on their habitat. Terrestrial plants are those that live on land and include trees, shrubs, and herbs found in forests, grasslands, and deserts. These plants have roots adapted to absorb water from soil and leaves adapted to reduce water loss. Aquatic plants are those that live in water environments such as ponds, lakes, and rivers. These plants have special adaptations like floating leaves, air-filled tissues, and roots that absorb nutrients directly from water. Both types of plants are well-suited to their respective environments.
1-Mark Questions (MCQ)
The pond is an example of ………
(b) Freshwater habitat
Ch 5Living World of Animals
5-Mark Questions
A habitat is a living or dwelling place of an organism. The geographical features and environmental conditions on earth remain the same from one place to another. Amoeba is a unicellular organism and moves with pseudopodia. Birds can see only one object at a time. Paramecium is a multicellular organism.
True False – The geographical features and environmental conditions on earth do not remain the same from one place to another. True True False – Paramecium is a unicellular organism.
How do the birds catch their prey?
The method by which birds catch their prey varies depending on the type of bird and the environment in which they live. Aquatic birds such as ducks, herons, and kingfishers use their specially adapted beaks to catch prey from water. These birds dive or wade into the water and use their beaks to catch fish and other aquatic organisms, often sliding them upside down into the water to secure their grip. …
2-Mark Questions
Where can we see camels in India?
Camels can be seen in the state of Rajasthan in India, which is their primary habitat. The main dwelling places and regions where camels are found include Jodhpur, Pushkar, Pikanur, and Jaisalmer. These areas are located in the Thar Desert region of Rajasthan, where the hot and arid climate is well-suited to the camel's physiology and lifestyle. Camels are well-adapted to survive in these desert regions and are commonly used for transportation and agricultural purposes by the local people.
Name the locomotory organs of an Amoeba.
The locomotory organ of an Amoeba is a finger-like projection called pseudopodia, which means false feet. The Amoeba uses these pseudopodia to move from place to place by extending them in the direction it wants to move and then flowing its cytoplasm into these projections. This allows the Amoeba to change shape and move slowly across surfaces in its aquatic environment. The pseudopodia also help the Amoeba to engulf and capture food particles.
What are the body parts of the snake?
The body of a snake is divided into three main parts: the head, the body, and the tail. The head contains several important sensory organs and structures. On the head, a snake has two eyes that help it see its surroundings, two nostrils that allow it to breathe and sense odours in the environment, and a mouth that is used for consuming prey. The body is the longest part and contains the internal organs, while the tail extends from the end of the body and helps the snake with movement and balance.
1-Mark Questions (MCQ)
The study of living things or organisms is called
b. Biology
Ch 6Health and Hygiene
5-Mark Questions
Differentiate between Carbohydrate and Protein.
Carbohydrates and proteins are two essential macronutrients that serve different functions in the body. Carbohydrates are energy-giving components of food that provide fuel for daily activities and bodily functions. Common sources of carbohydrates include nuts, fruits, rice, and maize. These foods are rich in sugars and starches that are broken down to release energy. Proteins, on the other hand, are body-building foods that are essential for growth, repair, and maintenance of body tissues, muscles, and organs. Proteins also help in the formation of enzymes and hormones. …
2-Mark Questions
There are three main nutrients present in food. Fats are used as an energy store by our body. All bacteria have flagella. Iron helps in the formation of haemoglobin. Virus can grow and multiply outside host.
False – There are six main nutrients present in food: carbohydrates, proteins, fats, vitamins, minerals, and water. True – Fats are used as an energy store by our body and also serve other important functions. False – Not all bacteria have flagella; some bacteria are non-motile and lack flagella. True – Iron helps in the formation of haemoglobin, which is essential for carrying oxygen in the blood. False – Viruses cannot grow and multiply outside a host cell; they require a living host cell to reproduce.
Define the term “Balanced diet”.
A balanced diet is a diet which contains a sufficient amount of various nutrients in the right proportions to ensure good health and proper functioning of the body. A balanced diet includes carbohydrates for energy, proteins for growth and repair, fats for insulation and energy storage, vitamins and minerals for various metabolic processes, and dietary fiber for digestion. It should provide all the necessary nutrients required by the body to maintain health, prevent diseases, and support physical and mental development.
Why should the fruits and vegetables not to be washed after cutting? Vitamins are of two types.
We should not wash the fruits and vegetables after cutting because water-soluble vitamins and minerals present in them will dissolve and be washed away with the water. When fruits and vegetables are cut, their cells are damaged and their nutrients become exposed to water. Vitamins such as vitamin C and B-complex vitamins are water-soluble and easily lost during washing. Additionally, minerals and proteins in the fruits and vegetables will also be washed away, reducing their nutritional value. …
1-Mark Questions (MCQ)
Our body needs for muscle-building
(c) Protein
Ch 7Heat
5-Mark Questions
Rivet is heated before fixing in the hole to join two metal plates.
When a rivet is heated before fixing in the hole to join two metal plates, thermal expansion takes place and the rivet becomes larger in diameter, allowing it to fit easily into the hole. The heat also makes the rivet softer and more malleable. One end of the rivet is then hammered to form a new head that is larger than the hole, preventing the rivet from passing through. When the rivet cools down after the hammering process is complete, it undergoes thermal contraction and shrinks back to its original size. …
Explain thermal expansion with suitable examples.
Thermal expansion: The expansion of a substance on heating is called, the thermal expansion of that substance. Fitting the iron rim on the wooden wheel: The diameter of the iron ring is slightly less than that of the wooden wheel. So, it cannot be easily slipped on from the rim of a wooden wheel. The iron ring is, therefore, first heated to a higher temperature so that it expands in size and the hot ring is then easily slipped over to the rim of the wooden wheel. Coldwater is now poured on the iron ring so that it contracts in size and holds the wooden wheel tightly. …
2-Mark Questions
An ordinary glass bottle cracks when boiling water is poured into it, but a borosilicate glass bottle does not.
An ordinary glass bottle cracks when boiling water is poured into it because ordinary glass has a high coefficient of thermal expansion. When the hot water comes into contact with the glass, the outer surface expands rapidly while the inner surface remains relatively cool and expands more slowly. This uneven expansion creates internal stress in the glass, causing it to crack. Borosilicate glass, on the other hand, does not expand much on being heated because it has a very low coefficient of thermal expansion. …
The electric wire which sag in summer become straight in winter.
During summer, the electric wire experiences thermal expansion due to the increase in temperature. The heat causes the molecules in the wire to vibrate more vigorously and move farther apart, resulting in an increase in the length of the wire. This causes the wire to sag between the poles. In winter, when the temperature decreases, the wire contracts as the molecules move closer together and vibrate less. This contraction reduces the length of the wire, making it become straight again.
Make a list of electrical types of equipment at home from which we get heat.
Common electrical equipment at home from which we get heat include water heaters used for heating water for bathing and washing, electric iron boxes used for pressing clothes, electric kettles used for boiling water quickly, microwave ovens used for cooking and heating food, electric room heaters used for warming rooms during winter, electric stoves and cooktops used for cooking, and electric toasters used for toasting bread.
1-Mark Questions (MCQ)
When an object is heated, the molecules that make up the object
(a) begin to move faster
Ch 8Electricity
5-Mark Questions
In a parallel circuit, the electricity has more than one path. To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell. The switch is used to close or open an electric circuit. Pure water is a good conductor of electricity. Secondary cell can be used only once.
In a parallel circuit, electricity has more than one path – True. To make a battery of two cells, the negative terminal of one cell is connected to the positive terminal of the other cell – True. The switch is used to close or open an electric circuit – True. Pure water is a good conductor of electricity – False, pure water is an insulator because it lacks ions; only impure water containing dissolved salts is a conductor. Secondary cells can be used only once – False, secondary cells can be recharged and used many times, unlike primary cells which can be used only once.
Can you produce electricity from a lemon?
Yes, we can produce electricity from a lemon using it as a simple electrochemical cell. To create a lemon cell, insert a copper plate on one side of the lemon and a zinc strip or safety pin on the other side. The lemon juice acts as an electrolyte containing ions that allow chemical reactions to occur between the two different metals. The copper plate serves as the positive terminal and the zinc strip or safety pin serves as the negative terminal. …
2-Mark Questions
What type of circuit is there in a torchlight?
A simple circuit system is used in a torchlight. This circuit consists of a battery or dry cell as the power source, a switch to control the flow of electricity, connecting wires to complete the path, and a bulb that produces light. When the switch is pressed, it closes the circuit and allows current to flow from the battery through the wires to the bulb, causing it to glow. When the switch is released, the circuit opens and the current stops, turning off the light.
Draw the circuit diagram for the series connection.
Silver is a good conductor but it is not preferred for making electric wires. Why?
Although silver is an excellent conductor of electricity with very high conductivity, it is not preferred for making electric wires because it is an extremely costly and precious metal. The high cost of silver makes it economically impractical and unaffordable for large-scale use in electrical wiring. Instead, copper and aluminum are preferred because they are good conductors of electricity, readily available, relatively inexpensive, and can be easily drawn into wires. This makes them much more suitable for practical applications in homes, industries, and electrical systems.
1-Mark Questions (MCQ)
The device which converts chemical energy into electrical energy is
(c) cell
Ch 9Changes Around Us
5-Mark Questions
Growing of teeth in an infant is slow change. Burning of match stick is a reversible change. Change of New moon to Full moon is human made. Digestion of food is a physical change. In a solution of salt in water, water is the solute.
Growing of teeth in an infant is a slow change – True. Burning of a match stick is a reversible change – False, burning of a match stick is an irreversible change because the match stick cannot be restored to its original form once burned. Change of New moon to Full moon is a human-made change – False, the change from New moon to Full moon is a natural change caused by the relative positions of the Earth, Moon, and Sun in space. …
What happens when cane sugar is strongly heated? Mention any two changes in it.
When cane sugar is strongly heated, it undergoes significant transformations. Initially, the solid sugar melts into a liquid due to the application of heat, which is a physical change. As heating continues, the sugar begins to decompose chemically, turning brown and then black in colour as the sugar molecules break down. During this decomposition, fumes are released into the air. The changes involved are both physical change, in the initial melting stage, and chemical change, during the decomposition process. …
2-Mark Questions
Growth of a child, Blinking of eye, Rusting, Germination of a seed.
Blinking of an eye is a fast change because it occurs in a fraction of a second. Fast changes are those that happen very quickly in a short period of time, usually in seconds or minutes. In contrast, growth of a child is a slow change taking months or years, rusting is a slow chemical change taking days or weeks, and germination of a seed is a slow change taking several days. Blinking is an involuntary reflex action of our eyelids that protects our eyes and happens almost instantaneously.
Glowing of a bulb, lighting of a Candle, breaking of a coffee mug, curdling of milk.
Curdling of milk is a chemical change because new substances are formed during this process. When milk curdles, the milk proteins coagulate and separate into curds and whey due to the action of bacteria or acid, resulting in a completely different substance that cannot be easily reversed to its original form. In contrast, glowing of a bulb is a physical change involving light emission, lighting of a candle involves both physical melting of wax and chemical combustion, breaking of a coffee mug is a physical change where the shape changes but the material remains the same, and curdling of milk i …
Rotting of an egg, condensation of water vapour, trimming of hair, Ripening of fruit.
Trimming of hair is a man-made change because it is deliberately caused by human action using scissors or other tools. Man-made changes are those that occur due to human intervention and are intentionally brought about by people. In contrast, rotting of an egg is a natural change caused by decomposition, condensation of water vapour is a natural physical change caused by temperature decrease, and ripening of fruit is a natural biological change that occurs as part of the fruit's life cycle without human intervention.
1-Mark Questions (MCQ)
When ice melts to form water, change occurs in its
(c) State
Ch 10Air
5-Mark Questions
1. Plants manufacture food by a process called photosynthesis. 2. Plants require energy for their growth. 3. Plants take in oxygen and release carbon-di-oxide just as animals. 4. Plants take carbon-di-oxide from the atmosphere, use chlorophyll in the presence of sunlight and prepare food. 5. Such oxygen is available to animals and human beings for breathing. 6. During this process, oxygen is released by plants.
Plants are essential for maintaining life on Earth through the process of photosynthesis. Plants require energy for their growth and development. To obtain this energy, plants manufacture food by a process called photosynthesis. During photosynthesis, plants take carbon dioxide from the atmosphere and use chlorophyll in the presence of sunlight to prepare their own food. As a result of this process, oxygen is released by plants into the atmosphere. This oxygen is available to animals and human beings for breathing and respiration. …
What will happen if we remove plants from the aquarium?
If we remove plants from the aquarium, several negative consequences will occur. The production of oxygen will be reduced significantly because plants are the primary producers of oxygen through photosynthesis. At the same time, the absorption of carbon dioxide and ammonia will be reduced, leading to an accumulation of these gases in the water, which can harm the fish. Plants provide shelter and hiding places for fish, making them feel secure. Without plants, fish will feel insecure and stressed. …
2-Mark Questions
What will happen if we remove the fish from the aquarium and keep it (with green plants) in a dark place?
If we remove the fish from the aquarium and keep it with green plants in a dark place, the plants will not be able to carry out photosynthesis because photosynthesis requires light energy. Without photosynthesis, the plants will not produce oxygen, and the oxygen level in the water will gradually decrease. The plants may eventually die due to lack of light. Additionally, without fish, there will be no source of carbon dioxide and nutrients that fish waste provides, which plants need for their growth. The aquarium will become an imbalanced ecosystem unable to sustain life.
How do the roots of land plants get oxygen for breathing?
Roots of land plants obtain oxygen for respiration from the air spaces present in the soil. Soil contains numerous pores and spaces between soil particles that are filled with air. Root hairs, which are tiny extensions of root cells, come into contact with this air in the soil. Oxygen from these air spaces is taken up by the root hairs through the process of diffusion, where oxygen molecules move from areas of higher concentration to areas of lower concentration. …
What will happen if you breathe through your mouth?
Breathing through your mouth instead of your nose can lead to several health problems. When you breathe through your mouth, the air bypasses the nose, which normally filters, warms, and humidifies the air before it reaches the lungs. This can result in dry mouth and throat as moisture is lost more rapidly. Mouth breathing can cause snoring, especially during sleep. It may lead to daytime tiredness and fatigue because mouth breathing is less efficient than nasal breathing. …
1-Mark Questions (MCQ)
……… is the percentage of nitrogen in the air.
(a) 78%
Ch 11The Cell
5-Mark Questions
Shiva said, “Bigger onion has larger cells when compared to the cells of the smaller onion”! Do you agree with his statement or not? Explain why?
No, Shiva's statement is incorrect. The bigger onion and smaller onion both contain plant cells, and the size of individual cells remains essentially the same whether they come from a small onion or a large onion. All plant cells of the same type have similar dimensions. The reason a bigger onion appears larger is not because its cells are bigger, but because it contains a greater number of cells. The larger volume and mass of the bigger onion result from having more cells packed together, not from having larger individual cells. …
Why cells are called building blocks of life?
Cells are called the building blocks of life because they are the basic structural and functional units of all living organisms. Just as bricks are the fundamental units used to construct a wall, cells are the fundamental units that make up all plants, animals, and other living things. Every living organism, whether unicellular or multicellular, is composed of one or more cells. Cells carry out all the life processes necessary for survival, including growth, reproduction, metabolism, and response to the environment. …
2-Mark Questions
Elephant, Cow, Bacteria, Mango, Rose plant.
The correct order from smallest to largest is: Bacteria, Mango, Rose plant, Cow, Elephant. Bacteria are single-celled prokaryotic organisms and are microscopic in size. Mango and rose plants are multicellular organisms, with mango trees being smaller than rose plants in general. Cow and elephant are both large multicellular animals, with the elephant being significantly larger than the cow.
Hen Egg, Ostrich egg, Insect egg.
The correct order from smallest to largest is: Insect egg, Hen egg, Ostrich egg. Insect eggs are typically microscopic or very small in size. Hen eggs are medium-sized eggs that we commonly use in our daily lives. Ostrich eggs are the largest eggs among birds and are significantly bigger than hen eggs.
Who discovered the cell in 1665?
The English scientist Robert Hooke discovered the cell in 1665 while examining thin slices of cork tissue under a microscope. He observed small, box-like structures that reminded him of the cells in a monastery, so he named them cells. This discovery was groundbreaking because it was the first time the basic unit of life had been identified and described.
1-Mark Questions (MCQ)
The unit of measurement used for expressing dimension (size) of cell is
(c) micrometer
Ch 12Human Organ Systems
5-Mark Questions
Blood is produced in the bone marrow. All the waste products of the body are excreted through the circulatory system. The other name of the food pipe is an alimentary canal. Thin tube-like structures which are the component of the circulatory system are called blood vessels. The brain, the spinal cord, and nerves form the nervous system.
The first statement is False because red blood cells (RBCs) are produced in the bone marrow, not all blood components. The second statement is False because all waste products of the body are transported through the circulatory system, not excreted directly by it; excretion occurs through organs like kidneys and lungs. The third statement is False because the other name of the food pipe or digestive tract is the alimentary canal, which is correct terminology. …
Describe the skeletal system.
The skeletal system is a complex framework that consists of bones, cartilages, and joints working together to support and protect the body. Bones provide a rigid framework that gives shape and structure to the body and protects vital internal organs such as the brain, heart, and lungs. Cartilage is a flexible connective tissue found in areas like the nose, ears, and between vertebrae, providing cushioning and flexibility. Joints are the points where bones meet and are held together by ligaments, allowing movement between bones. …
2-Mark Questions
Stomach → Large intestine → Oesophagus → Pharynx → Mouth → Small Intestine → Rectum → Anus
The correct sequence of the digestive pathway is: Mouth → Pharynx → Oesophagus → Stomach → Small intestine → Large intestine → Rectum → Anus. Food enters through the mouth where it is chewed and mixed with saliva, then passes through the pharynx and oesophagus into the stomach where it is further broken down, moves into the small intestine for nutrient absorption, then into the large intestine where water is absorbed, and finally exits through the rectum and anus.
Urethra → Ureter → Urinary Bladder → Kidney
Kidney → Ureter → Urinary bladder → Urethra
Write the functions of epiglottis?
The epiglottis is a small, leaf-shaped flap of tissue that serves two important functions in the respiratory and digestive systems. It prevents the entry of food into the windpipe (trachea) by covering the opening of the larynx during swallowing, ensuring that food goes down the oesophagus instead. When air is being inhaled, the epiglottis opens and moves upward to allow air to pass freely into the windpipe and lungs. This mechanism ensures that food and air follow their correct pathways and prevents choking.
1-Mark Questions (MCQ)
The circulatory system transports these throughout the body
(d) All of these
Ch 13Parts of Computer
2-Mark Questions
Name the parts of a computer.
A computer consists of three main parts. The Input unit receives data and instructions from the user through devices like keyboards, mice, and scanners. The Central Processing Unit (CPU) is the brain of the computer that processes all the data and instructions received from the input unit. The Output unit displays or produces the processed information in a form that users can understand, such as through monitors, printers, and speakers.
1-Mark Questions (MCQ)
Which one of the following is an output device?
(c) Speaker
Ch 14Magnetism
5-Mark Questions
A cylindrical magnet has only one pole. Similar poles of a magnet repel each other. Maximum iron filings stick in the middle of a bar magnet when it is brought near them. A compass can be used to find East-West direction at any place. Rubber is a magnetic material.
False – A cylindrical magnet has two poles. True False – Maximum iron fillings stick in the poles of a bar magnet when it is brought near them. False – A. compass can be used to find north-south direction at any place. False – Rubber is a non-magnetic material.
You are provided with an iron needle. How will you magnetize it?
To magnetize an iron needle, place it on a table in a horizontal position. Take a bar magnet and hold one of its poles near one end of the needle. Rub the magnet along the length of the needle from one end to the other in a single direction without reversing the direction of the magnetic pole. Repeat this stroking process 30 to 40 times, always moving in the same direction. This repeated unidirectional stroking aligns the magnetic domains within the iron needle, causing it to become magnetized. …
2-Mark Questions
Iron, nail, pins, rubber tube, needle
Iron, nails, pins, and needles are magnetic substances because they are attracted to magnets and can be magnetized. Rubber tube is a non-magnetic substance because it is not attracted to magnets and cannot be magnetized. Magnetic substances are typically made of iron or iron-based materials, while non-magnetic substances like rubber, plastic, and wood do not respond to magnetic forces.
Lift, escalator, electromagnetic train, electric bulb
Lifts, escalators, and electromagnetic trains use electromagnets in their operation. Electromagnets are temporary magnets created by passing electric current through coiled wire and are essential for these devices to function. Electric bulbs do not use electromagnets; instead, they produce light through the heating of a filament or through other light-emitting mechanisms when electric current passes through them.
Attraction, repulsion, pointing direction, illumination
The main magnetic properties are attraction, repulsion, and pointing direction. Attraction occurs when a magnet pulls magnetic materials towards it. Repulsion happens when two similar poles of magnets push away from each other. Pointing direction is the property by which a magnet always aligns itself in the north-south direction when freely suspended. Illumination is not a magnetic property as it refers to the emission of light, which is unrelated to magnetism.
1-Mark Questions (MCQ)
An object that is attracted by a magnet.
b. Plain pins
Ch 15Water
5-Mark Questions
Water present in rivers, lakes and ponds is unfit for use by human beings. Seas are formed when the water table meets the land surface. The evaporation of water takes place only in sunlight. Condensation results in the formation of dew on grass. Seawater can be used for irrigation as such.
The statement 'Water present in rivers, lakes and ponds is unfit for use by human beings' is False because water from these sources is actually fit for use by human beings, though it may require treatment and purification before drinking. The statement 'Seas are formed when the water table meets the land surface' is False because seas are large bodies of salt water formed by geological processes and are not formed by the water table meeting land. …
These vapours condense to form tiny droplets of water. The water droplets come together to form large water droplets. The heat of the sun causes evaporation of water from the surface of the earth, oceans, lakes, rivers and other water bodies. The large water droplets become heavy and the air cannot hold them, therefore, they fall as rains. Water vapour is also continuously added to the atmosphere through transpiration from the surface of the leaves of trees. Warm air carrying clouds rises up. Higher up in the atmosphere, the air is cool. These droplets floating in the air along with the dust particles form clouds.
The heat of the sun causes evaporation of water from the surface of the earth, oceans, lakes, rivers and other water bodies. Water vapour is also continuously added to the atmosphere through transpiration from the surface of the leaves of trees. These droplets floating in the air along with the dust particles form clouds. Warm air carrying clouds rises up. Higher up in the atmosphere, the air is cool. These vapours condense to form tiny droplets of water. The water droplets come together to form large water droplets. …
2-Mark Questions
Name four different sources of water.
Four different sources of water are rivers, wells, lakes, and glaciers. Rivers are flowing bodies of water that carry fresh water from mountains to plains and eventually to the sea. Wells are deep holes dug into the ground to access groundwater stored in underground layers. Lakes are large bodies of fresh water that collect in depressions on land and serve as important water sources for many regions. Glaciers are large masses of ice found in mountainous regions and polar areas that contain frozen fresh water. …
How do people in cities and rural areas get water for various purposes?
People in cities and rural areas get water for various purposes through different sources and systems. In cities, water is typically supplied through municipal water supply systems that deliver treated water through pipes and hand pumps to households. In rural areas, people obtain water from wells, which are dug to access groundwater stored underground. Canals are used in agricultural regions to distribute water for irrigation purposes. Tanks and ponds serve as storage systems for collecting and storing water during rainy seasons for use throughout the year. …
We could see clouds almost every day. Why doesn’t it rain daily?
We can see clouds almost every day, but it does not rain daily because rain occurs only under specific atmospheric conditions. Clouds form when water vapour in the air condenses into tiny water droplets, but these droplets are too light to fall as rain. For rain to occur, the air around the clouds must be sufficiently cool, and the water droplets in the clouds must combine and become heavy enough to fall as precipitation. If the air around the clouds is warm, the water droplets evaporate back into water vapour and the clouds disappear without producing rain. …
1-Mark Questions (MCQ)
Around 97% of water available on earth is water.
c. salty
Ch 16Chemistry in Everyday Life
5-Mark Questions
Concentrated phenol is used as a disinfectant. Gypsum is largely used in medical industries. Plaster of Paris is obtained from heating gypsum. Adhesives are the substances used to separate the components. NPK are the primary nutrients for plants.
The first statement is False because low concentrated phenol is used as a disinfectant, not concentrated phenol. Concentrated phenol is corrosive and harmful. The second statement is False because gypsum is largely used in medical and construction industries, not just medical industries. The third statement is True because plaster of Paris is indeed obtained from heating gypsum at controlled temperatures. The fourth statement is False because adhesives are substances that are used to join two or more components together, not to separate them. Adhesives create bonds between materials. …
Pour that solution into an empty matchbox, soap can be obtained after drying. Take the necessary quantity of water in a jar. Then add coconut oil drop by drop and stir it well. Add concentrated sodium hydroxide in the jar and allow it to cool. Try this soap to wash your handkerchief. Cover your work area with old newspaper.
The correct procedure for making soap at home is as follows: First, cover your work area with old newspaper to protect it from spills and stains. Take the necessary quantity of water in a jar. Add concentrated sodium hydroxide to the water carefully and allow the mixture to cool, as this reaction generates heat. Once cooled, add coconut oil drop by drop to the mixture and stir it well continuously to ensure proper mixing and saponification. Continue stirring until the mixture thickens and reaches a soap-like consistency. …
2-Mark Questions
What are the three main constituents of soap?
The three main constituents of soap are lye (sodium hydroxide), which is a strong alkali that reacts with oils; coconut oil or other oils and fats, which are the main ingredients that undergo saponification; and water, which acts as a solvent and medium for the chemical reaction. When these three components are mixed together under proper conditions, a chemical reaction called saponification occurs, in which the sodium hydroxide breaks down the oil molecules and converts them into soap molecules and glycerin.
What are the two different types of molecules found in the soap?
The two different types of molecules found in soap are water-loving molecules, also called hydrophilic molecules, which have an affinity for water and are attracted to water molecules, and water-hating molecules, also called hydrophobic molecules, which repel water and are attracted to oils and fats. The water-loving end of the soap molecule is ionic and polar, while the water-hating end is non-polar and resembles the structure of oil molecules. …
Give an example of inorganic fertilizer.
Examples of inorganic fertilizers include urea, which is a nitrogen-rich fertilizer commonly used to provide nitrogen to plants; ammonium sulphate, which supplies both nitrogen and sulphur to the soil; and superphosphate, which is a phosphorus-rich fertilizer that provides phosphorus for plant growth. These inorganic fertilizers are manufactured chemically and provide essential nutrients in concentrated forms that are readily available for plant absorption, making them effective for increasing crop yield and plant growth.
1-Mark Questions (MCQ)
Soaps were originally made from ………
b. animal fats and vegetable oils.
Ch 17Our Environment
5-Mark Questions
The pacific ocean is an example of an aquatic ecosystem. Bacteria and fungi are called decomposers. Human and animal wastes are examples of non-biodegradable waste. Excessive use of pesticides leads to air pollution. In schools, waste management rules say that we should separate waste in two categories.
The Pacific Ocean is indeed an example of an aquatic ecosystem where living organisms interact with their physical environment. Bacteria and fungi are correctly called decomposers because they break down dead organic matter and return nutrients to the soil and water. However, human and animal wastes are examples of biodegradable waste, not non-biodegradable waste, because they can be decomposed by microorganisms and natural processes. Excessive use of pesticides leads to land pollution and water pollution, not just air pollution, as pesticides seep into soil and water bodies. …
What is biodegradable waste?
Biodegradable waste refers to materials that can be easily broken down and decomposed by natural agents and microorganisms. These natural agents include water, oxygen, ultraviolet rays from the sun, and decomposing microorganisms such as bacteria and fungi. Common examples of biodegradable waste include vegetable and fruit peels, leftover food, grass clippings, leaves, twigs, paper, cardboard, and animal manure. When biodegradable waste is disposed of properly, it decomposes naturally and returns to the soil as nutrients, enriching it and making it fertile for growing plants. …
2-Mark Questions
Rabbit → Carrot → Eagle → Snake. Human → Insect → Algae → Fish
The correct food chains are: Carrot → Rabbit → Snake → Eagle and Algae → Insect → Fish → Human. In the first chain, the carrot (producer) is eaten by the rabbit (primary consumer), which is then eaten by the snake (secondary consumer), and finally by the eagle (tertiary consumer). In the second chain, algae (producer) is consumed by the insect (primary consumer), which is eaten by the fish (secondary consumer), and finally by humans (tertiary consumer). The order must follow the direction of energy flow from producers to consumers.
Define ecosystem.
An ecosystem is a community of living organisms (biotic components) and non-living things (abiotic components) that interact and work together in a specific environment. The biotic components include plants, animals, bacteria, and fungi, while the abiotic components include sunlight, water, air, soil, temperature, and humidity. All these elements are interconnected and dependent on each other, forming a balanced system where energy flows and nutrients cycle continuously.
What are the two types of ecosystems?
The two main types of ecosystems are terrestrial ecosystems and aquatic ecosystems. Terrestrial ecosystems are found on land and include forests, grasslands, deserts, and mountains where organisms are adapted to living on soil with varying amounts of rainfall and temperature. Aquatic ecosystems are found in water bodies such as oceans, rivers, lakes, and ponds where organisms are adapted to living in freshwater or saltwater environments with specific conditions of light, temperature, and dissolved oxygen.
1-Mark Questions (MCQ)
Identify the freshwater ecosystem.
d. All of them
Ch 18Plants in Daily Life
5-Mark Questions
Plants grown for decorative purposes are called as softwood. Silkworm eats mulberry leaves. Cauliflower is used for ornamental purpose. Cotton cloth is not suitable for summer season. Sugarcane is used as biofuel.
False – Plants grown for decorative purposes are called as ornamental plants. True. False – Cauliflower is used for edible purpose. False – Cotton cloth is only suitable for summer season False – Sugarcane is used to produce sugar.
What is a symbiotic relationship?
A symbiotic relationship is an interaction between two different organisms where both organisms benefit from each other. This mutually beneficial relationship is economically and ecologically significant. One example is the relationship between silkworms and mulberry plants. Silkworms feed on mulberry leaves for nutrition and growth, and in return, they produce silk fibres that are valuable to humans. Another example is the relationship between honey bees and flowering plants. …
2-Mark Questions
What are the medicinal plants?
Medicinal plants are plants that possess healing properties and are used to treat, cure, or prevent diseases and health conditions. These plants contain various chemical compounds and active ingredients that have therapeutic effects on the human body. Examples of common medicinal plants include neem, which has antibacterial properties, tulsi or holy basil used for respiratory health, turmeric known for its anti-inflammatory properties, and aloe vera used for skin healing. Many traditional and modern medicines are derived from these plants. …
Name any three medicinal plants, which are available in your area?
What are the uses of timber?
Timber is wood obtained from trees and has multiple important uses. Timber is extensively used in the construction of buildings as a structural material and for making doors, windows, and frames. It is also used in the manufacture of furniture such as tables, chairs, and cabinets. Additionally, timber is used in making fibreboard, which is a composite material used in various applications. Timber is also an important raw material in paper making. The durability, strength, and aesthetic qualities of timber make it a valuable resource for many industries and applications.
1-Mark Questions (MCQ)
One of the following birds is an example of plant-pollinator
c. Hummingbird
Ch 19Hardware and Software
5-Mark Questions
What are Hardware and Software?
Hardware: Hardware is the parts of the computer which we can touch and feel. Hardware includes input and output devices, Cabinet, Hard disk, Mother Board, SMPS, CPU, RAM, CD Drive, and Graphics card. Software : Software is programmed and coded application to process the input information. The software processes the data by converting the input information into coding or programmed language. Touching and feeling is not possible. But, we can see the functions of the software in the form of output.
What do you mean by Operating System? How does it work?
An Operating System is a system software that acts as an intermediary between the user and the computer hardware. It manages all the hardware devices and controls how they work together to process the data inputted by the user and display the results on output devices like a monitor. The operating system performs essential functions such as managing files, controlling peripheral devices, allocating memory, and executing programs. Without an operating system, the computer cannot function on its own because there would be no way to communicate with the hardware or run any programs. …
2-Mark Questions
What are the types of software?
Software is divided into two main types based on its function and purpose. The first type is System Software, which includes the Operating System. System software manages the computer's hardware and provides a platform for other programs to run. The second type is Application Software, which consists of programs designed for specific tasks that end-users perform on their computers. Application software includes programs like word processors, web browsers, games, and educational tools. …
1-Mark Questions (MCQ)
Find out the part that is not found in the CPU?
d. Mouse
Frequently asked questions
- The distance between the two places is 43.65 km. convert it into meter and cm.
- (a) Convert km into metre 1 km = 1000m ∴ 43.65 km = 43.65 × 1000 = 43650.00 = 43650 = 43650 m. (b) Convert km into cm. 1 km = 1000 m 1 m = 100 cm 1 km = 1000 × 100 cm 1 km = 100000 cm ∴ 43.65 km = 43.65 × 100000 = 4365000.00 = 4365000 cm.
- What are the rules to be followed to make an accurate measurement with scale?
- To make an accurate measurement with a scale, several important rules must be followed. First, always ensure that the object being measured is placed parallel to the scale so that it aligns properly with the markings. Second, start the measurement from the zero mark of the scale rather than from the edge, as this ensures accuracy and avoids errors. Third, take care to read the correct submultiple or division on the scale, as misreading can lead to significant errors. …
- We can say that mass an object is 126 kg Length of one’s chest can be measured by using metre scale. Ten millimetres makes one centimetre. A hand span is a reliable measure of length. The SI system of units is accepted everywhere in the world.
- False. Mass is a measure of the amount of matter in an object, and it is measured in kilograms (kg) or grams (g). While the statement mentions 126 kg, it incorrectly associates it with the length of one's chest. False. The length of one's chest is typically measured using a measuring tape or a flexible ruler, not a metre scale, which is designed for longer distances. True. Ten millimetres are indeed equivalent to one centimetre (1 cm = 10 mm). False. A hand span is a traditional unit of length but is not considered a reliable measure because it varies from person to person. True. …
- Sugar: Beam Balance, Lime Juice?
- Sugar is measured using a beam balance to determine its mass or weight. Lime juice is measured using a graduated cylinder because it is a liquid and volume measurement is appropriate. The height of a person is measured in centimetres (cm). The length of a sharpened pencil lead is measured in millimetres (mm) because of its small size. Milk, being a liquid, is measured by volume using a graduated cylinder or measuring cup. Vegetables are typically measured by their weight or mass using a beam balance or weighing scale. …
These important questions are selected from the Samacheer Kalvi Class 6 Science textbook book-back exercises to help you revise the most useful questions. Mark weightage (5/2/1) follows the usual exam pattern and may vary by exam — always check your latest syllabus and question pattern. Open each chapter for the complete set of questions and answers.