Rawhiya

Energy is the ability to do work or cause change, and it exists in many forms such as kinetic, potential, thermal (heat), light, sound, electrical, chemical, and nuclear energy. One of the most important rules in science is the law of conservation of energy, which states that energy cannot be created or destroyed—it can only be transferred or transformed from one form to another. For example, a battery changes chemical energy into electrical energy, a light bulb converts electrical energy into light and heat, and plants transform sunlight into chemical energy through photosynthesis. Energy is constantly changing forms in nature and in everyday life, powering everything from moving vehicles and growing plants to weather systems and living organisms. The efficiency of these energy transformations depends on the system, and some energy is often transferred as heat. Understanding energy helps explain how the world works, making it one of the most…

Heat is the transfer of thermal energy from a hotter object to a cooler one because of a difference in temperature. Unlike temperature, which measures how hot or cold something is, heat is energy that is always moving until both objects reach the same temperature, a state called thermal equilibrium. Heat can travel in three ways: conduction, where particles pass energy through direct contact; convection, where warm liquids and gases rise while cooler ones sink, creating currents; and radiation, where energy travels as electromagnetic waves and does not need a medium, allowing the Sun to warm the Earth through space. The speed of heat transfer depends on factors such as the material, temperature difference, surface area, and insulation. Metals are excellent conductors because their free electrons carry energy quickly, while materials like wood, plastic, and air are insulators that slow down heat transfer. Heat transfer is responsible for countless natural…

Static electricity is the build-up of electric charges on the surface of an object. It is called static because the charges stay in one place until they are released. It is usually produced when two materials are rubbed together, causing tiny electrons to move from one object to another. One object becomes negatively charged, while the other becomes positively charged. When the charges become too large, they suddenly move to another object, creating a small electric shock or a tiny spark. Common examples of static electricity include rubbing a balloon on your hair, clothes sticking together after drying, and lightning, which is a very powerful form of static electricity.

Air resistance is a contact force that acts against the motion of an object moving through the air. It is caused by collisions between the object and tiny air molecules. These collisions create a force that acts in the opposite direction of the object's movement, slowing it down. The amount of air resistance depends on the object's speed, shape, and surface area. Faster-moving objects experience greater air resistance because they collide with more air molecules in a shorter time. Objects with a larger surface area, such as parachutes, also experience more air resistance. To reduce this force, engineers design airplanes, racing cars, and high-speed trains with streamlined shapes so they can move more efficiently. Air resistance plays an important role in transportation, sports, and the motion of falling objects.

• Object or surface rough against one another, it cause of course known as friction.

• Friction work against a motion because act in the opposite direction.

• Frictional force is cause by tiny irregularities and electromagnetic attraction between surfaces. It opposes slipping, not always motion itself,and can even help objects move when we walk.Friction can also produce heat and cause wear and tear.

Force is an interaction between objects that can change an object’s motion, speed, direction, or shape. Forces are mainly divided into contact forces and non-contact forces. Contact forces act when objects physically touch each other. Examples include friction, which opposes motion between surfaces, and air resistance, which acts against an object moving through the air. Non-contact forces act from a distance without direct physical contact. These include gravitational force, which attracts objects with mass, magnetic force, which causes attraction or repulsion, and electrostatic force, which acts between electrically charged objects. When the forces acting on an object are balanced, the net force is zero and its motion does not change. When the forces are unbalanced, the net force causes the object to speed up, slow down, or change direction.

Force is everywhere in our daily life. When you walk, your feet push against the ground, and the ground helps push you forward. When you throw a ball, the force from your hand makes it move. When the ball falls, gravity pulls it toward Earth.

The amount of force is measured in newtons (N) using a device called a force meter or newton meter. A stronger push or pull means a greater force.

An important idea is that a force can change an object's motion. A heavier object usually needs more force than a lighter object to produce the same change in motion. Friction can also oppose movement, which is why a rolling ball eventually slows down and stops.

Forces often act together. Scientists use arrows to show forces: the arrow points in the direction of the force, and a longer arrow represents a stronger force.

The ozone layer is a thin but very important layer of ozone gas (O₃) found in the stratosphere, about 15–35 km above the Earth's surface. It acts like a protective shield around our planet by absorbing about 97–99% of the Sun's harmful ultraviolet (UV) radiation, especially UV-B and UV-C rays. These rays can damage the DNA of living cells and cause skin cancer, cataracts, sunburn, and weaken the immune system in humans. They can also harm animals, reduce crop growth, damage forests, and kill tiny marine organisms such as phytoplankton, which are an important part of the ocean food chain. By filtering out these harmful rays while allowing visible light and the warmth needed for life to reach Earth, the ozone layer makes our planet safe for plants, animals, and humans. Without the ozone layer, life on Earth would be much more difficult, and many living organisms might not survive.…

Magnets

- A magnet is an object that attracts certain metals.

- Magnets attract iron, steel, nickel, and cobalt.

- Every magnet has two poles: North and South.

- Opposite poles attract each other.

- Like poles repel each other.

Definition

Force is a push or a pull that can change the motion, direction, speed, or shape of an object.

Main Details

Force is a push or pull.

It is measured in newtons (N).

Definition

Energy changing form is the process in which energy changes from one type to another type. Energy is not lost; it only changes its form.

Main Details

Energy can change between different forms like heat, light, sound, electrical, chemical, kinetic, and potential energy.

Energy cannot be created or destroyed.

Most machines work because energy changes form.

📘 Definition

Air resistance is the force of air that pushes against an object when it moves through the air and slows it down.

📌 Main Details

It acts in the opposite direction of motion.

It is also called drag.

The faster an object moves, the stronger the air resistance.

Definition

Sedimentary rocks are rocks formed from small pieces of rocks, sand, and remains of plants and animals that settle in layers and become hard.

Examples

Sandstone

Limestone

Shale

🌍 Rocks, Materials, and Soil (Easy Way)

🪨 What are rocks?

Rocks are hard things found on the Earth.

They are made of minerals.

We see rocks on mountains, roads, and riverbeds.

Examples: stone, granite, marble

Definition

Day and night happen because the Earth rotates (spins) on its axis.

Main details

The Earth spins once in 24 hours.

The side of Earth facing the Sun has day.

The side of Earth facing away from the Sun has night.

Definition

Fossils are the remains or traces of plants and animals that lived on Earth long ago and got preserved in rocks.

Main Details

Fossils form over millions of years.

They are usually found in sedimentary rocks.

Fossils help scientists learn about ancient life and Earth’s history.

Definition

Thermal energy is the energy produced by heat due to the movement of tiny particles inside an object.

Main details

Everything around us is made of tiny particles.

These particles are always moving.

When particles move faster, the object has more thermal energy.

Definition

The Moon is Earth’s natural satellite, and moon phases are the different shapes of the Moon that we see from Earth as it moves around Earth and reflects sunlight.

Main Details

The Moon does not produce its own light; it shines because it reflects sunlight.

It takes about 29½ days for the Moon to complete one full cycle of phases.

The Moon phases change gradually because of the relative positions of the Sun, Earth, and Moon.

Definition

Moving planets are planets that travel through space by moving in fixed paths called orbits around the Sun.

Main Details

Planets do not stay still; they are always in motion.

Each planet moves around the Sun in an oval-shaped path called an orbit.

This movement is called revolution.

Definition

Soil is the top layer of the Earth where plants grow. It is made of small rock pieces, water, air, and dead plants and animals.

Main Details

Soil forms very slowly over a long time.

It gives plants nutrients and support.

Soil holds water needed by plants.

Definition

Electricity is a form of energy that comes from the movement of tiny charged particles called electrons.

It helps us run lights, fans, phones, computers, and many machines.

🔹 Main Details About Electricity

Electricity flows through materials called conductors (like copper).

Materials that do not allow electricity to pass are called insulators (like rubber and plastic).

KINETIC ENERGY

Definition

Kinetic energy is the energy an object has because it is moving.

Main Details

It depends on movement

The faster an object moves, the more kinetic energy it has

Defenition

Friction is a force that resists the motion of one surface over another. It slows down or stops moving objects.

Main details

Friction happens when two surfaces touch each other.

It can be helpful or unhelpful.

There are different types of friction:

Definition:

Seeing forces means observing the effects of a force on objects, even though the force itself cannot be seen.

Main details:

A force is a push or a pull. Forces can make objects move, stop, change speed, change direction, or change shape. We know a force is acting when we notice these changes. Forces can be contact forces (touching) or non-contact forces (without touching).

Examples:

Wind moving leaves

1. Magnets attract materials like iron, nickel, and cobalt.

2. Every magnet has two poles — north and south.

3. Like poles repel, and unlike poles attract.

4. The area around a magnet where its force acts is called the magnetic field.

5. Magnets can be natural or artificial.

6. Compass needles use magnets to show direction.

1. Push

2. Pull

3. Motion

4. Vector

5. Magnitude

6. Direction

1. An electromagnet is made by winding a wire into a coil and passing electric current through it.

2. The magnetic field is produced only when electricity flows in the coil.

3. The strength of an electromagnet depends on the number of coil turns and the amount of current.

4. Electromagnets are temporary magnets, which means they lose magnetism when the current stops.

5. They are used in devices like electric bells, cranes for lifting scrap iron, motors, and speakers.

1. Gravity is a force that pulls everything toward each other.

2. It keeps us standing on the ground and not floating away.

3. When we drop something, gravity makes it fall down.

4. Gravity is the reason we have weight.

5. The Sun’s gravity keeps all the planets moving around it.

6. The Moon goes around Earth because of Earth’s gravity.

Examples:

1. Railway tracks – small gaps are left so they don’t bend in hot weather.

2. Bridges – expansion joints are added to allow safe expansion.

3. Thermometers – the liquid inside rises when heated.

4. Electric wires – they sag in summer because they expand.

5. Metal lids on jars – lids loosen easily if dipped in hot water, as the metal expands.

1. Earth is the planet where humans, animals, and plants live.

2. It is the third planet from the Sun.

3. About 71% of Earth is water and 29% is land.

4. The land is divided into 7 continents.

5. There are 5 main oceans on Earth.

6. It spins once in 24 hours, causing day and night.