Kids Learning Science

 

4th Standard Science Term-I

Science in Everyday Life

Learning Objectives

After Leaning this lesson, students will be able to

✩ know the nutritional value of milk.

✩ explore the benefits of cooking.

✩ learn about baking of bread, biscuit and cake.

✩ know about gadgets used in daily life.

Let us Recall

Teacher : What do you drink in the morning.?

Students : Tea, coffee and milk.

Teacher : Good.  What do they contain?

Ram : Milk, tea dust, coffee powder, sugar and water.

Teacher : Very good.  Do you know why we drink milk?

Ram : It is good for our health.

Teacher : Correct, let us learn more about milk in this lesson.

  I. Milk  

Milk is produced by mammals for nourishing their young ones.  Milk from many animals is used by humans.  Cow's milk is used commonly.

  1. Sources of Milk  

Milk is primarily obtained from mammals.  It is also obtained from other sources.  

Examples : Soya milk, nut and seed based milk.

  2. Nutritional value of Milk  

Milk contains water, sugar, protein, fat, vitamins and minerals.  Based on the amount of fat present in the milk, it can be classified as whole milk, low fat milk and fat free milk.

Sugar : Milk has sweet taste because it has a special sugar called lactose.

Protein : It helps to build muscles.

Fat : Fat present in the milk is called butter.  Butter is more delicious than any other fat.

Vitamins : Vitamin-D in milk helps to maintain the bones.

Minerals : Calcium is a mineral.  It helps to build healthy bones and teeth.

Do you Know

People all over the world get their milk from mammals like sheep, goat, camel, donkey, horse, yak, water buffalo, reindeer and even moose.

Primary food for babies.

Gives curd, butter, butter milk and ghee.

Health drink for adults and sick people.

Used for making cheese, paneer and milk sweets.

Used in ice cream and chocolates.

Used during festivals and ceremonies.

  3. Health Benefits of Milk  

1. It strengthens bones and teeth.

2. It maintains blood pressure. 

3. It reduces the risk of heart disease.

4. It is a source of energy.

  II. Food materials  

What is food? Food is one of the basic needs of our life.  Food provides energy.  It is usually made by cooking plants or animals.  It contains essential nutrients to keep our body healthy.

Food can be classified into two types.

1. Raw Food - Raw food is the food that does not need to be cooked to eat.

Examples : Fruits, carrot, ground nut seeds.

2. Cooked food - Cooked food is the food, that has been cooked to eat. 

Examples : Rice, vegetable curry, bread.

  Let us Do  

Simple tasks such as pouring liquid into the bowl, sprinkling pepper on the omelet or dosa, Peeling off onions, powdering coriander seeds can be done by you.  Always help the elders in the kitchen.

  1. Cooking  

Do you know how many food items are there that you will not be able to eat without cooking? Cooking is important.  It makes food suitable for consumption.

  Methods of Cooking  

  Benefits of Cooking  

Cooking causes many useful changes in food.

1. It makes nutrients ready for digestion.

2. It helps to make food in the desired texture, flavour and taste.

3. It destroys harmful microbes.

  Let us Discuss  

Look at the things shown in the picture and discuss their uses with your friends.

  III. Baking of Bread, Biscuit and Cake  

Baking is a method of cooking.  We use heat to bake, biscuit and cake are some examples of baked food items.

  1. Bread  

Bread s a common food item prepared by baking the dough.  It is an important source of energy for sick people.  It is also one of the ancient foods made by humans.  Bread is a low fat food.

Bread has the nutrients required for normal development and good health.

To make bread we need wheat flour, yeast, water, sugar and salt.

Do you Know

Bread gets spoiled six times faster when kept in fridge than at room temperature.

  2. Biscuit  

Biscuit is a small, flour - based baked food.  It is generally made of wheat flour or oats sweetened with sugar.

The main ingredients of biscuit are flour, sugar, butter, water, milk, baking powder and flavours.

Biscuits are salty or sweet.  Some biscuits have cream in between.

  3. Cake  

Cake is a baked dessert.  It is like a sweet bread.  There are many varieties of cake with specific ingredients.  We use cake during celebrations.  The common ingredients of cake are flour, sugar, eggs, oil, baking powder and flavouring agent.

  Activity  

Visit a bakery near you and learn about baking of bread, biscuit and cakes.

  IV. Gadgets  

Think of the electronic devices we use everyday.

The phone that we use, the camera that comes with us on every vacation, the TV that we watch for fun, all these devices are called gadgets.

A gadget is a small electronic machine or device which does something useful.  Number of gadgets have changed our lives.  They make our life enjoyable.

Examples : 

Laptop

Phone

Camera

Pen drive

Speaker

  Smart Phones  

Apart from communication smart phones have the ability to access the internet and store files, take photos, track location and much more.

  Portable Music Player   

It stores and plays thousands of songs.  We can listen to songs anywhere, anytime.

  Tablets  

People use tablets to read books, play games and watch videos.

  Pen Drive  

It is a small gadget used for storing and transferring any type of file in / from a computer.

  Electric Torch  

It is a portable hand-held electric light.  It is used to provide light in the dark places when it is switched on.

Kids Learning Science

 

4th Standard Science Term-I

Work and Energy

Learning Objectives

After learning this lesson students will be able to

✩ define work.

✩ understand work and energy.

✩ know simple machines.

✩ classify types of machine.

✩ know about three types of lever.

  Let us Recall  

Teacher : Students, you have studied about force in your lower class.  What is force?

Students : A force is a push or pull that moves an objects at rest or stops an object in motion.

Teacher : There are different kinds of force.  What are they?

Students : Frictional force, Gravitational force, Muscular force and Magnetic force.

A Force can cause an object to change its shape, speed or direction.

  I. Work  

An action in which one exerts a force to move an object is known as work.  What do you understand from the pictures given below?

From these pictures, we understand that a force is applied to do some work.

  Think and Say  

Teacher : Yesterday I was walking back from the school.  I found some people working to lay the road.  I found some items in that place.  Can you say something about that place and the machines that were used there?

When can we say that work is done or not?

Two main conditions are needed for work to be done.

• A force should act on an object.
• Object should move from one place to another.

  II. Energy  

✩  The car moves by the energy obtained from the burning of fuel.

✩  The escalator moves by using electricity as energy.

Energy is defined as capacity of doing work.

Energy must be transferred to an object in order to do work.

  1. Renewable Resources  

Renewable sources of energy are replaced naturally over a period of time.  We can keep using these sources for a long period of time.  Since the beginning of human life, we have been using these resources.  We use these resources for lighting, transport, cooking, heating.  Eg: Sun, Wind and Water.

  2. Non-renewable Resources  

The resources which are not easily replaced once used are called the non-renewable resources.  

Eg: Petrol, Coal and Natural gas.

  More to Know  

The law of conservation of energy states that energy can neither be created nor destroyed.  It can be converted from one from to another.

The SI unit of energy is joule.

It is named after James Joule who explained about energy.

  III. Simple Machine  

Observe the above pictures.  What are they used for?

In our daily life our effort is saved with the help of some simple machines.

We draw water from the well with the help of a wheel and a rope.

Simple machines are tools which are used to make our work easier.  Some example for simple machines are pulley, wedge, inclined plane, screw, lever, wheel and axle.

  1. Pulley  

Observe the picture.  Which is easier? Lifting the load with the help of a pulley or without a pulley?

A pulley is a machine made up of a wheel with a cut around it.  A rope or chain passes around the pulley.  It rotates in the direction with more force.  Eg: Crane

  2. Inclined Plane  

Observe the picture and discuss.  Is lifting a box is easier than rolling it on a ramp?

An inclined plane is a flat sloping surface with one end higher than another.

Eg: Ramp, slide and slope for wheel chair.

  3. Wedge  

A wedge is a tool with a sharp edge which can be used to split materials.  It is used to break wooden logs into two pieces.  Eg: Knife, scissors and axe.

  4. Screw  

The screw is used to raise weights and to hold objects together.  Eg: Pencil sharpener, screw-jack, bottle cap and windmill.

The screw in the bottle cap holds the cap and the bottle together.  

These blade and sharpener are held together by screw.

  5. Wheel and Axle  

Wheel and axle consist of a wheel attached to a small rod so that these two parts rotate together.

Eg: Bicycle wheel, door knob, grinder, axle wheel.

  More to Know  

Simple machines usually exchange a smaller fore to move a heavy object.  The work required is the same, but the force required is less.  The idea of a simple machine originated with the Greek philosopher Archimedes around the 3rd century BC.

  6.  Lever  

A lever is used to multiply the force we give on an object.  Eg: See saw, nut cracker and plier.

  IV. Types of Lever  

To understand the lever, we must know the following terms.

Load is the object on which the force is applied.

Effort is the force we apply on the lever.

Fulcrum is the point on which the lever rotates.

Lever is classified into three types according to where the load and effort are located with respect to fulcrum. 

  1. Class I Lever  

When the fulcrum is between the effort and the load, it is known as Class I lever.  

Eg: Scissors, pliers, seesaw.

  2. Class II Lever  

When the load is between the effort and the fulcrum, it is known as class II lever.  

Eg: Wheel barrow, lemon squeezer, nut cracker.

  3. Class III Lever  

In this lever, the effort is between the load and the fulcrum.  

Eg: Stapler, tongs, broom stick, hockey stick. 

Kids Learning Science

 

4th Standard Science Term-I

Matter and Materials

  I. Materials  

Everything in the universe is a matter.  We need to explore many different materials to make sense of our world.

The matter from which a thing is made of is called material.  

For example : Chair is made of wood, Eraser is made of rubber, Candle is made of wax.

  II. Properties of Materials  

We can measure, see or feel the materials.  Different types of materials have different properties that make them useful for various purposes.  Most materials have more than one property.  They can be hard or soft, shiny or dull, smooth or tough and flexible or rigid.

  1. Hard and Soft Materials  

Materials which cannot be easily compressed, cut, bent or scratched are called hard materials.  

Example : Brick, bone and steel.

Materials which can be easily compressed, cut, bent or scratched are called soft materials.

Example : Foam, clay and skin.

  2. Shiny and Dull Materials  

Materials which reflect the light well are called shiny materials.  

Example : Stainless steel, gold and diamond.

Materials which do not reflect the light well are called dull materials.

Example : Candle, Paper and jute bag.

  Try to Answer  

Collect some objects from your house and classify them as shiny or dull materials.

  3. Rough and Smooth Materials  

Materials which have ups and downs on their surface are called rough materials.  

Example : Brick, rock and tyre.

Materials which do not have ups and downs on their surface are called smooth materials.  

Example : Mirror, silk cloth and tiles.

  4. Flexible and Rigid Materials  

Materials which can be bent or stretched easily are known as flexible materials. 

Example : Rubber band, electric wire and cycle tube.

Materials which cannot be or stretched easily are known as rigid materials.  

Example : A stick, wooden scale and stone.

  5. Waterproof Materials  

Materials that do not allow water to pass through them are called waterproof materials.

Example : Raincoat and aluminium foil of tablet strip.

  Think and Answer  

  Do you have a raincoat? What is its use?  

  Activity  

Take a glass bowl.  Fill three fourth of it with water.  Put an orange fruit with peel and a orange fruit without peel.  Observe which orange floats? Why?

  III. Transparent, Translucent and Opaque objects  

  Have you ever seen through the bus window?  

Some objects allow light to pass through them.  This helps us to see through them as the window of a bus.  Let us see how different objects behave with light.

  1. Transparent Objects  

Transparent objects allow the light to pass through them.  So, we can see other objects clearly through transparent objects.  Example : Air, glass and pure water.

  2. Transparent Objects  

Some light passes through

                                       Vegetable oil

Translucent objects allow some light to pass through them.  So, we cannot see objects clearly, but we see them as blurred images through them.

Examples : Paper soaked in oil, snow and vegetable oil.

  3. Opaque objects  

Opaque objects do not alIow light to pass through them.  So, we cannot see through these objects.

Examples : Wood, Stone and metals.

  Think and Answer  

  Why should we build the walls of the house with bricks (opaque material) instead of glass (transparent material)?  

  IV. Reflection of Light  

We see the world around us with the help of light.  Where do we get the light from? Light may come either from the Sun or from other sources like an electric lamp or a bulb.   The objects that give off light are called light sources.

When light falls on a transparent material it passes through it.  However when light falls on a polished surface of an opaque material, it does not pass through it.  It bounces back.  The bouncing of light by any smooth or polished surface is called reflection.

When you look into the mirror, you can see your own face on the mirror.  What you see is a reflection of your face in the mirror.  We also see reflections of other objects that are in front of the mirror.  These reflections are formed by light and they are called images.

  Try to Answer  

Try to see your face on some materials like mirror, exam pad, new stainless steel plate, table top and water in a plate.  What are the materials that show your face clearly? Do you know why?

  Activity  

Reflection of Light

Material Required/Needed

A plane mirror and a torch light.

How to do?

1. Make your room dark by closing the door and windows.

2. Ask your friend to hold a mirror in his/her hand at one corner of the room.

3. Stand at another corner with a torch in your hand.

4. Switch it on.

5. Direct the light from the torch onto the mirror.

6. Answer the following from your observation.

a) When you change the angle of the mirror, what happens to the light?

b) Are you able to direct the reflected light using the mirror?

  More to Know  

Mirrors can reflect sound waves too.  So they were used in the Second World War to detect sounds coming from enemy aircraft.