Soil Erosion and Soil Conservation - Class 5 Science - New St. Mery English School 

Soil is one of the most important natural resources on Earth. It helps plants grow, provides food for us, and supports all living things. But sometimes soil gets carried away by wind, water, or human activities. This wearing away of the soil is called soil erosion. Soil erosion makes the land less fertile and can even lead to floods and loss of crops.

To protect the soil, we use different methods. These methods are called soil conservation. Soil conservation helps to save the soil from being washed or blown away. It also helps to keep the land healthy for farming and for future generations.

In this chapter, you will learn what soil erosion is, its causes, and how we can protect the soil through different conservation methods.

Soil Erosion and Soil Conservation - Class 5 Science - New St. Mery English School

What is Soil?

Ans:- The top layer of earth where plants grow is called soil. It contains many things such as small pieces of rock, air, water, humus and living organisms.

How does soil form?

Ans:- soil is formed when rocks breakdown into tiny pieces due to continuous drying, heating and cooling by the sun, rain and wind. this is called weathering. this repeated weathering over thousands of years break the rock into small pieces and thus, soil is formed. soil formation is very slow, long and continuous process.

What factors does the colour of soil depend on?

Ans:- The colour of soil depends on the minerals present in rock by which soil is formed. 

What is weathering?

Ans:- Breaking of rocks into small particles by rain, wind and the sun is called weathering.

Write five importance of soil.

Ans:- The five importance of soil are

1- Soil provides suitable conditions for plant's growth

2- All types of plant food are produced in soil.

3- Soil helps in the storage of underground water.

4- Forests grow in soil which help in bringing rain.

5- Soil provides shelter to various animals such as ants, earthworms, rabbits etc.

What is Soil Erosion?

Ans:- Soil erosion is the process of removal, wearing away, or washing away of the top layer of soil by natural forces like wind, water, or human activities.

Causes of Soil Erosion

1. Heavy Rainfall – washes away soil.

2. Strong Winds – blow loose soil.

3. Floods – carry away soil with water.

4. Deforestation – cutting trees removes roots that hold soil.

5. Overgrazing – animals eat plants and expose soil.

6. Poor farming methods – loosen and expose soil.

Effects of Soil Erosion

1. Loss of fertile soil

2. Decreased crop production

3. Formation of deserts (desertification)

4. Loss of plants and trees

5. Water pollution due to soil mixing in water bodies

How to Prevent Soil Erosion

1. Planting trees (afforestation)

2. Terrace farming

3. Contour ploughing

4. Building embankments

5. Avoiding overgrazing

Soil Conservation

Soil Conservation means protecting the soil from being damaged, lost, or washed away. It includes all the methods that help save soil, improve soil quality, and prevent soil erosion.

Write five ways by which we conserve soil.

Ans:- The five ways by which we conserve soil are

1- By afforestation

2- By building bunds or embankments along river banks

3- By growing plants in farm lands

4- By avoiding overgrazing

5- By step farming in Hilly areas

What is Afforestation?

Ans:- Growing of trees on large scale is called afforestation.

What is reforestation?

Ans:- Reforestation is the process of growing trees again in a place that once had a forest.

Rocks and Minerals - Class 2 Science - New St. Mery English School

This chapter explains what rocks are, how they are formed, and the different types of rocks we see around us. Students will also learn what minerals are and why they are important in our daily life. The explanation is simple, clear, and perfect for young learners, teachers, and parents looking for easy science notes for Class 2. 

Rocks and Minerals - Class 2 Science - New St. Mery English School

What are Rocks?

Ans:- Rocks are hard, solid materials that are found on the Earth.They are all around us - on the ground, in mountains, in gardens, and even under the soil.

How many types of rocks?

Ans:- There are two types of Rocks

1- Hard Rocks

2- Soft Rocks

What are Hard Rocks? Give example.

Ans:- Rocks that are very strong and cannot be easily broken are called Hard Rocks.

Ex:- Marble, Granite, Sand stone etc

What are Soft Rocks?

Ans:- Those rocks which can be easily broken, cut, or scratched are called Soft Rocks.

Ex:- Chalk, Slate, Coal

What is Marble?

Ans:- Marble is a hard rock that is used to make statues, buildings and floor tiles. It comes in many colours like pink, grey, black, brown, green, red and white.

Write a monument that is made of white marbles.

Taj Mahal

What is Granite?

Ans:- Granite is a hard rock that is used to make buildings, kitchen slabs, floor tiles and statues. It comes in many colours like black, grey, pink and white etc

What is Sand stone?

Ans:- Sand stone is a hard rock that is used to make building. It comes in many colours like red, brown and yellow.

What is chalk?

Ans:- Chalk is a soft rock that is used to make chalks to write on blackboard.

What is Slate?

Ans:- Slate is a soft rock that is used to make roofs of houses and blackboard.

What is Coal?

Ans:- Coal is a soft black rock that is used as a fuel.

What are Minerals?

Ans:- The solid substances which are present naturally in the rocks are called minerals.

Ex:- China clay, quartz, talc, graphite, silica, sand and gemstones

What is talc?

Ans:- Talc is a softest mineral. It is used to make talcum powder.

What is graphite?

Ans:- Graphite is a soft and slippery mineral. It is used to make pencil lead.

What is Silica Sand?

Ans:- Silica Sand is a mineral. It is used to make glass which is used to make utensils, mirrors and table tops etc.

What are gem stones?

Ans:- Gem stones are beautiful minerals. It is used to make jewellery.

Write a mineral that is used to cut glass?

Ans:- Diamond

Motion and Time - Class 7 Science - New st. Mery English School

This chapter explains different types of motion such as uniform and non-uniform motion, measurement of time, and the use of simple devices like sundials, sand clocks, and water clocks. Students will also learn how to calculate speed, draw distance–time graphs, and observe motion in daily life with simple examples. Perfect for CBSE Class 7 students, teachers, and parents looking for clear and well-structured science notes.

Motion and Time - Class 7 Science - New st. Mery English School

 What is Motion?

Ans:- Motion is the change in position of an object with respect to its surroundings in a given interval of time.

Ex:- A moving car, A flying bird, A rolling ball, A moving train

How many types of motion?

Ans:- There are four types of motion.

1- Rectilinear Motion

2- Circular Motion

3- Periodic Motion

4- Rotational Motion

What is Rectilinear Motion?

Ans:- Motion along a straight line is known as Rectilinear Motion. It is also known as linear motion or Motion in a straight line.

Ex:- A car moving on a straight road, A train moving on a straight track, A laser beam travelling in a straight line, A ball rolling straight on the floor

Key points of Rectilinear Motion

1- In Rectilinear Motion, object does not change its direction.

2- In Rectilinear Motion, The path is straight.

3- In Rectilinear Motion, Speed may be uniform or non-uniform, but the path remains straight.

What is Circular Motion?

Ans:- The motion of an object in a circular path along the circumference of a circle is known as Circular Motion.   

Ex:- The movement of The hands of a clock, A stone tied to a string and swung in a circle, The Earth revolving around the Sun

Key points of Circular motion

1- In circular motion, The object keeps changing its direction, but stays on a circular path.

2- In circular motion, There is always a fixed centre around which the motion takes place.

What is Periodic Motion?

Ans:- A motion that repeats itself after equal intervals of time is known as Periodic Motion.

Ex:- Swinging pendulum of a clock, Heartbeat, Revolution of the Earth around the Sun, Day and night cycle

Key points of Periodic Motion

1- The Periodic motion happens in a pattern.

2- Each cycle of Periodic motion takes the same amount of time, known as the time period.

What is Rotational Motion?

Ans:- When an object spins or turns about a fixed axis, the motion is called rotational motion.

Ex:- The Earth rotating on its axis, Spinning top, Wheels of a bicycle or car

Key points of Rotational Motion

1- In Rotational Motion, The object does not move from one place to another, it spins in its own position.

2- In Rotational Motion, The line about which it rotates is called the axis of rotation.

Slow Motion and Fast Motion

An object that takes longer time to cover a certain distance is said to be exhibit slow motion but An object that takes less time to cover the same distance is said to be exhibit fast motion. 

When an object covers more distance in a short time, it is said to be in fast motion.

Ex:- A car moving at high speed.

        A cheetah running.

        A train moving quickly.

        A fan spinning at high speed.

When an object covers less distance in a long time, it is said to be in slow motion.

Ex:- A tortoise walking.

        A person walking slowly.

       The movement of a snail.

       The hands of a clock (hour hand).

How to Compare Fast and Slow Motion?

We compare  Fast and Slow Motion using speed. 

If two objects cover different distances in the same time

The one covering more distance → faster

The one covering less distance → slower

Ex:- A bicycle covers 10 km in 1 hour and A scooter covers 30 km in 1 hour. Here the scooter is faster than cycle because it covers more distance in the same time.

Speed

The distance travelled by an object in per unit of time is called Speed.

SI unit of distance is Metre. SI unit of time is Second.

So The SI unit of speed is Metre / Second (m / s ).

Formula of Speed:

$$\text{Speed} = \frac{\text{Distance}}{\text{Time}}$$

Example:

If a car travels 100 km in 2 hours. Find its speed.

Solution:- Distance = 100 km

                  Time = 2 hour

                 

$$\text{Speed} = \frac{100}{2} = 50 \text{ km/h}$$Uniform and Non-Uniform Motion

Uniform Motion

When an object covers equal distances in equal intervals of time, the motion is called uniform motion.

Example:- A car moving at constant speed, like 40 km/h.

                A train moving without stopping and without changing speed.

               If a car covers 10 km every 10 minutes, its motion is uniform.

Non-uniform Motion

When an object covers unequal distances in equal intervals of time, the motion is called non-uniform motion.

Example:- A car moving in traffic (sometimes slow, sometimes fast).

                 A child running in a playground, changing speed.

Distance - time graph

Distance - Time graph is a line graph which shows the relation between distance travelled and time taken to travel that distance by a moving body. In the distance - time graph , distance is plotted on the Y-axis and time is plotted on the X-axis.

Steps to draw Distance-time graph

Step - 1

Take a graph sheet and make two mutually perpendicular axis on it. Label the horizontal  as X-axis and the vertical as Y-axis.

Step - 2

Put marking on the X-axis and Y-axis as per the data given in the table with appropriate multiple units. The scale of the graph should be mentioned on the top right side of the graph.

Step - 3

Finally, the points are put on the graph corresponding to data given on the X-axis and Y-axis

Step - 4

All the encircled points are joined together, It results in the formation of distance-time graph.

Precautions while making Distance-Time Graph

Time

Time is the continued progress of events from the past, through the present, and into the future.

Time is the way we measure how long things take or when events happen.

Ancient methods of measuring time

The time interval between one sunrise and the next is a unit of time called day.

The time period from one sunset to sunrise is called night.

Time interval between one moon and the next is called a month.

Sundial

A sundial is a device that tells the time of the day by using the shadow made by the sun.

It has two main parts:

1. Dial Plate – A flat surface with hour markings.

2. Gnomon – A stick or triangular plate that casts a shadow.

When sunlight hits the gnomon, it creates a shadow on the dial plate. The position of this shadow tells the time.

How Does a Sundial Work?

• When the sun rises in the east, the shadow falls to the west.

• At noon (12 PM), the shadow is the shortest.

• In the evening, the shadow becomes long and falls toward the east.

The sundial uses this movement of the shadow to show the time.

Uses of a Sundial

• To tell time during the daytime

• To study the movement of the sun

• Used in ancient times before clocks were invented

Limitations of a Sundial

• It does not work at night

• It cannot work on cloudy or rainy days

• Time is not very accurate compared to clocks

1- The graph should be plotted using a sharp pencil and a ruler.

2- The scale of the graph should be taken appropriately according to the minimum and maximum observations.

Note:-

1- A straight line distance-time graph shows uniform motion.

2- When this graph is not a straight line, than it shows that body is executing non-uniform motion.

Cleaning of food and separation of substances - Class 6 Science - New St. Mery English School 

This lesson covers why food needs to be cleaned before cooking and the different methods used to remove impurities. Students will also understand various separation techniques such as handpicking, winnowing, sieving, sedimentation, decantation, filtration, evaporation, and distillation. Perfect for CBSE Class 6 students, teachers, and parents looking for clear notes with simple examples.

Cleaning of food and separation of substances - Class 6 Science - New St. Mery English School

 1:- What is substance?

Ans:-  substance is a matter which has specfic composition or properties.

Ex- sugar, salt etc.

Every pure element is a substance. Every pure compound is a substance.

2:- How many types of substance? Name them.

Ans:- There are three types of substance

1-Pure substance

2- Impure substance

3- Mixture

3:- What is pure substance?

Ans:-A substance that contaons only one element or compound is called pure substance.

For example:- iron, water, sugar, salt etc.

4:- What is impure substance?

Ans:-  Impure substance is made up of two or more than two elements or compounds that are not bounded together chemically.

For example:- sugar in water, sand in water, fruit juice, muddy water etc.

5:- What is mixture?

Ans:-A mixture is the physical combination of two or more substances in which all substances are retained their identities. The components of mixture can be separated by physical mean.

Ex- salt water, mixture of water and sugar

Write three features of mixture.

Ans:- The three features of mixture are

1- The constituents  of a mixture are not present in a fixed ratio.

2- No chemical reaction takes place among the constituents of a mixture.

3- The constituents of a mixture retain their original properties.

6:- How many types of mixture? Name them.

Ans:- There. are three types of mixture.

1-Solid mixture

2-liquid mixture

3-gaseous mixture

7:-Write two example of solid mixture.

Ans:-soil, food grains

8:- Write six example of liquid mixture.

Ans:- tap water, syrup, a cup of tea, sea water, petroleum

9:- write an example of gaseous mixture.

Ans:- air

Why do we need to separate the substances from a mixture?

Ans:- we need to separate the substances from a mixture for the following reason.

1- To remove undesirable and harmful substances.

2- To obtain pure substances

3- To obtain desirable substances

10:- How many types of practices that can be help us in separating solid from other solid?

Ans:- There are five practices that can be help us in separating solid from other solid.

1-harvesting

2-threshing

3-winnowing

4-Hand picking

5-sieving

11:- what is harvesting?

Ans:- Harvesting is the process of gathering ripe crops from the field.There are two methods to harvest crops.

1-By hand using sickle

2-By harvester

12:- Write short notes on hand harvesting using sickle.

Ans:- Hand harvesting is done by small farmers. In hand harvesting crops are cut by hand using sickle at the root level. The harvested crop plants are made into stacks and are dried in sun. The dried stacks are then thrashed to separate grains from the stalks and the husk.

13:- What is Threshing?

Ans:- Threshing is the process of loosening the edible part of grain from the chaff to whichit is attached. 

 

14:- Write short notes on threshing.

Ans:- Threshing is a process in which crops are thrashed to get fine grains. Threshing is done by three process.

   1- By beating on hard surface

   2- Trampling by the cattle

   3- By thresher

15:- Write short notes on the trampling by the cattle.

Ans:- In trampling by cattle harvested spikes are sprad on the ground in a circle and bullocks tied to a central axis are made to walk over them in rounds. Cattle's tread upon the spikes and their hoofs help separate the grains, leaving behind a mixture of broken straw, chaff and the grains.

16:- What is winnowing?

 Ans:- Winnowing is farming method   developed by ancient people for     seperating grain from chaff.

17:- Write short notes on winnowing.

  Ans:- Winnowing is used to separate fine grains from straw and chaff with help of blowing wind. In this method farmers stand on a high platform facing the direction of wind and releasing the mixture of straw, chaff and grains form a winnow. Grains beings heavier fall under the winnow. Straw and chaff are being lighter and belown a little away by wind.

18:- What is hand picking?

Ans:- Hand picking is used to remove undesirable components like small pieces, and many other impurities from the grains.

19:- Write two places where hand picking is used.

Ans:- The two places where hand picking is used are 

      1- In separating impurities from grains.        2- In separating unripe fruits from ripe fruits.

20:- What is sieving?

Ans:- Sieving is a process in which fine particles are separated from bigger particles by using sieve.

21:- Write six places where sieving process is used to separate fine particles from large particles.

Ans:- The six places where sieving process is used are.

  1- Separate large sized grains from finer impurities.

  2- Separate bran from flour.

  3- Grade nuts of different sizes.

  4- Separate fine sand from coarse sand or pebbles.

  5- Large pearls from small pearls.

  6- Precious stones of different sizes.

22:- What is floating and sinking method?

Ans:- Floating and sinking method is used to separate the two components from a mixture in which both are solids but one floats and other sinks in water. 

         For example - To remove the dust and straw from the grains.

How many types of practices that can be help us in separating solid from liquid?

Ans:- There are two practices that can be help us in separating solid from liquid.

1-Sedimentation and decantation

2-Filtration

23:- What is Sediment?

Ans:- Insoluble solid particles which settle down in water is called sediment.

For example:- soil, chalk, sand etc.

24:- What is sedimentation?

Ans:- The process in which insoluble solid settling down in water is called sedimentation.

25:- What is decantation?

Ans:- pouring out liquid without disturbing the sediments is called decantation.

26:- What is solute?

Ans:- The substance that is soluble in any medium is called solute.

For example- sugar, salt, wax etc.

27:- What is solvent?

Ans:- The liquid in which a solute gets dissolved is called a solvent.

For example:- water, milk, kerosene etc.

28:- What is solution?

Ans:- The transparant mixture that is formed when solute dissolve in solvent is called solution

For example:- mixture of water and salt, mixture of water and sugar

29:- What are miscible liquids?

Ans:- Liquids which mix together in all proportions and form a single layer are called miscible liquids.

For example- milk and water , glycerine and water etc.

30:- What are immiscible liquids?

Ans:-  Liquids which do not mix with each other and form separate layers are called immiscible liquids.

For example- solution of oil and water

31:- What is loading?

Ans:- Loading is a process in which the rate of sedimentation is increased by adding chemical substances like alum.

32:- How does alum work as a loading in muddy water? Explain.

Ana:-  Alum is highly soluble in water. Particles of alum get attached to the clay of muddy water. This increases the weight of mud particles. These heavy particles of alum and dust together settle down fast. And make the water clean fastly.

33:- What is filtration?

Ans:- Filtration is a process that is used to separate an insoluble impurities from a liquid. Strainer, filter paper, wire-mesh and clothes are used as filter equipment for filtration.

34:- Write the name of some solid liquid mixture that is filtered by filtration process.

Ans:-Milk from milkman which include some straw

water from river or pond that have have solid impurities

Tea is filtered for separate tea leaves

35:- What is evaporation?

 Ans:- The process by which a liquid changes into gas is called evaporation.

36:- How can be increase the rate of evaporation?

 Ans:- We can increase the rate of evaporation by.

     1- Increase the temperature

     2- Increase the surface area of liquid

     3- By fast blowing air

37:- What is crystallization?

 Ans:- Formation of crystals of salt on evaporation of water from a solution of salt is called crystallization.

38:- What is condensation?

 Ans:- The process by which a gas or water vapour changes into liquid is called condensation.

39:- Write three magnetic metal names.

 Ans:- 1- Iron 

           2- Cobalt 

           3- Nickel

40:- What is magnetic separation?

 Ans:- Magnetic separation is the process of separating magnetic materials from magnetic and non magnetic mixture with the help of magnet.

   For example - we can separate mixture                of iron filings and sand by the.                       process of magnetic separation.

41:- What is churing?

  Ans:- Churning is the process that is used to separate cream from milk or curd.

42:- How many types of machines are used in churning?

 Ans:- 1- Wooden ladle

           2- Electrically operated blender 

           3- Churner

43:- How churning helps us in getting butter from curd?

Ans:- Firstly curd is churned with the help of churning machine. Churning machine separates the butter from curd. Butter is lighter than the milky water therefor it start to float above the milky water. By this process we can separate butter from curd.

What is Centrifugation?

Ans:- Centrifugation is a process of separating components of a mixture by spinning it rapidly, so that heavier particles settle down and lighter particles remain on top.

 

Centrifugation is a method used to separate a mixture of solid and liquid or two liquids that have different densities.

It is done using a machine called a centrifuge, which spins very fast.

Ex:- Separating cream from milk

        Separating mud particles from water in a lab

        Separating blood components (in hospitals)

How does a centrifuge work?

Ans:- When the mixture is spun very fast in a centrifuge , heavier particles move to the bottom and Lighter particles stay at the top.

Force, Work and Energy - Class 4 Science - New St. Mery English School

Understand the basics of Force, Work and Energy with this easy and child-friendly Class 4 Science lesson. Learn what force is, types of forces like push, pull, muscular force, gravitational force, and friction, and how they affect objects around us. This lesson also explains what work is, when work is said to be done, and the different forms of energy such as heat, light, and motion. Perfect for CBSE Class 4 students, teachers, and parents looking for simple, clear, and well-explained science notes. 

Force, Work and Energy - Class 4 Science - New St. Mery English School

What is Force?

Ans:- Force is a push or pull on an object that can change its state of motion or shape. Force makes things move, stop, speed up, slow down, change direction, or change shape.

Write five effects of Force.

Ans:- The five effects of force are

1- It can move an object.

2- It can stop a moving object.

3- It can change the speed of moving object.

4- It can change the shape of an object

5- It can change the direction of a moving object.

How many types of force?

Ans:- There are many different types of forces, Some of them are

1- Muscular Force

2- Gravitational Force

3- Magnetic Force

4- Friction Force

What is Muscular Force?

Ans:-  The force that we apply using our muscles is called Muscular Force.

Ex:- Lifting a school bag, Kicking a football, Pushing a table, Riding a bicycle, Cutting vegetables with hands

What is Gravitational Force?

Ans:- Gravitational force is the force that pulls everything down toward the Earth.

Ex:- When you drop a ball, it falls down, Leaves fall from trees to the ground, Water flows downward

What is Magnetic Force?

Ans:- Magnetic force is the force by which a magnet attracts or repels certain objects. A magnet mainly attracts objects made of iron, nickel, or cobalt. These are called Magnetic substance.

Ex:- A magnet attracting pins or paper clips, A fridge magnet sticking to the refrigerator, A magnet pulling iron nails 

What is Friction Force?

Ans:- A force that slows down or stops a moving object is called Friction Force. It works between two surfaces which are in contact. Friction force is more on rough surface and less on smooth surface.

Ex:- When you rub your hands together, they become warm due to friction., We erase pencil marks on paper using friction.

Write five advantage of friction.

Ans:- The five advantage of friction are

1- Friction Helps us to stand, walk and run

2- Friction Helps vehicles move.

3- Friction Helps us in writing.

4- Friction Helps to stop moving objects.

5- Friction Helps us to hold things.

Write five disadvantages of friction.

Ans:- The five disadvantages of friction are

1- Friction produces heat that causes wear and tear of machines.

2- Friction tears the soles of shoes.

3- Friction Makes movement difficult.

4- Friction Wastes our energy.

5- Friction Reduces efficiency there for machines do not work smoothly.

What is work?

Ans:- Work is said to be done when a force is used to move something.

If you push, pull, lift, or carry an object and it moves, then work is said to be done.

Ex:- Pushing a table and it moves, Pulling a bucket from a well, Kicking a football and it rolls

What is Energy?

Energy is the ability to do work. We need energy to do all activities like walking, running, playing, reading, lifting things, and even breathing.

How many types of energy?

Ans :- There are many different types of energy, Some of them are

1- Solar Energy

2- Wind Energy

3- Hydro Energy

4- Fuel energy

What is solar energy?

Ans:- The energy that we get from sun is called solar energy.

Write three uses of solar energy.

Ans:- Three uses of solar energy are

1- Plants make food in the presence of solar energy.

2- Solar Energy is used to cook food using solar cooker.

3- Solar energy is converted into Electric energy using solar cell.

What is wind energy?

Ans:- The energy that we get from moving energy is called Wind Energy.

Write three uses of wind energy.

Ans:- The three uses of wind energy are

1- Wind energy is used to sail a boat.

2- Wind energy is used to run a wind mill.

3- Wind energy is used to generate electricity with the help of wind mill.

What is Hydro Energy?

Ans:- The energy that we get from moving water is called Hydro Energy.

Write an use of Hydro Energy.

Ans:- Hydro Energy is used to generate electricity.

What is Fuel Energy?

The energy that released by fuel like coal, LPG, kerosene, petrol, diesel and CNG is called fuel energy.

Write an use of Fuel Energy?

Ans:- Fuel energy is used to run machines and vehicles.

Measurement - Class 3 Science - New St. Mery English School 

Learn all about Measurement in this easy and child-friendly Class 3 Science explanation. This lesson covers what measurement is, why we need it, and the different units used to measure length, weight, and capacity. Students will also understand the difference between standard and non-standard units with simple examples. Perfect for CBSE Class 3 students, teachers, and parents looking for clear and helpful science notes.

Measurement - Class 3 Science - New St. Mery English School 

What is measurement ?

Ans- Measurement is the way to know the number of size or quantity of anything.

What is unit?

Ans:- Unit is a physical quantity that is used to measure anything.

Ex:- length is measured by kilometer or meter

        Weight is measured by Kilogram or gram

        Capacity is measured by liter or milliliter

        Time is measured by hour, minute or second

How many types of units?

Ans:- There are two types of units.

           1- Non-standard units

           2- Standard units

 

What are Non-standard units?

Ans:- Those units that vary from person to person are called Non-standard units.

          Ex:- handspan, cubit, stride and footspan

What are Standard units?

Ans:- Those units that are used for accurate measurement are called standard units.

          Ex:- Standard units for length are Kilometre, Metre, Centimetre

                  Standard units for weight are Kilogram, gram

                  Standard units for capacity are litre, mililitre

                  Standard units for time are hour, minute, second

Which unit is used to measure very small length?

Ans- Millimetre

Which unit is used to measure long lenght such as distance?

Ans:- Kilometre

What is the SI unit of length?

Ans:- Metre

Write the name of instrument that is used to measure length.

Ans:- Scale and Measuring tape

Which unit is used to measure weight of lighter things?

Ans:- Gram

Which unit is used to measure weight of heavier things?

Ans:- Kilogram

What is the SI unit of weight?

Ans:- Kilogram

Write the name of instrument that is used to measure weight.

Ans:- Weighing balance and Electronic weighing balance

Which unit is used to measure the capacity of smaller containers?

Ans- Millilitre

Which unit is used to measure the capacity of large containers?

Ans- Litre

What is the SI unit of capacity?

Ans:- litre

Write the name of instrument that is used to measure capacity.

Ans:- measuring cup, measuring cylinder, measuring flask

How did people know the time in ancient time?

Ans:- People knew the time in ancient time by the position of the Sun.

What is the SI unit of time?

Ans:- Second

 Soil - Class 3 Science - New St. Mery English School

Soil is one of the most important natural resources on Earth. It is the top layer of the ground that helps plants grow. All plants get water and nutrients from the soil. Many animals like earthworms and insects also live in it. In this chapter, we will learn about different types of soil, how soil is formed, and why it is so important for living things. Understanding soil helps us take better care of our environment and grow healthy plants.

Soil - Class 3 Science - New St. Mery English School

What is Soil?

Ans:- The topmost layer of the earth where plants grow and many animals like earthworms and insects live in is called Soil.

How is soil formed?

Ans:- Soil is formed from rocks. It is a very slow process. Soil is formed by breaking down of rocks into small pieces by the action of wind, rain and sun's heat. This process is called weathering. It takes millions of years for rocks to form soil.

What does soil contain?

Ans:- Soil contains following substances

              1- It contains small pieces of rocks.

              2- It contains dead and decaying plants and animals                            matter called humus.

              3- It contains water in between the spaces of soil                                  particles.

              4- It contains air that is trapped between the soil                                   particles.

How many types of soil?

Ans:- There are three types of soil

              1- Clayey soil

              2- Sandy soil

              3- Loamy Soil

What is Clayey soil?

Ans:- A type of soil that is very fine and does not have space for air between the particles and it can hold lot of water is called Clayey soil. It is sticky and good for making pots and toys.

What is Sandy soil?

Ans:- A type of soil that has big particles and trap alot of air between the particles. It is rough and does not hold water is called Sandy soil. It is found in desert or at seashores.

What is loamy soil?

Ans:- A type of soil that is the mixture of sandy soil and clayey soil is called loamy soil. It is brown in colour and rich in humus. It contains the right amount of air and water. It is the best soil for plants to grow.

Write four importance of soil?

Ans:- The four importance of soil are

          1- Plants grow in soil. They take water and minerals from                   the soil.

          2- Animals and human beings depend upon plants for food                 and they grow in the soil.

          3- Some animals live in the soil such as ants, earthworms,                   rabbits etc.

          4- Soilis used for pottery making, for making tiles and                         bricks and in making building materials.

Write different crops that grow in different soil

Ans:-     Clayey soil - Rice

              Sandy soil - Bajra

              Loamy soil - Wheat, Sugarcane

What is soil conservation?

Ans:- Taking care of soil from erosion is called soil conservation. We can protect soil by planting more trees.