Maheswari

Definition:

A 1950s British science fiction radio drama about astronauts traveling into space and facing adventures and dangers.

When did it happen?

• First aired in 1953.

• It was before humans went to space.

Key Points:

Definition:

The 400 years of astronomy is the time since 1609 when scientists began using telescopes to study space and made many important discoveries about planets, stars, and galaxies.

Key Points:

• Telescopes began being used in 1609 by Galileo Galilei

• The heliocentric model was accepted

• Planets move in elliptical orbits.

Geocentric Model:

Geocentric means “Earth-centered.”

This model said:

• Earth is at the center of the universe.

• The Sun, Moon, and planets move around Earth.

This idea was supported by:

What is the Moon?

The Moon is a big round space rock orbits the Earth.

Key Points:

• The Moon does not make its own light.

• It reflects sunlight.

• It takes about 27 days to go around Earth once.

Star:

A star is a huge ball of hot, glowing gas in space that makes its own light and heat.

Seeing Stars:

• Stars are huge balls of hot, glowing gas.

• They look tiny because they are very far away.

• Stars make their own light.

Definition:

A planet is a large object in space that moves around the Sun in a fixed path called an orbit.

Key points:

• Planets move around the Sun.

• They follow a fixed path called an orbit.

• The Sun’s gravity keeps them moving.

Definition:

The starry sky is the night sky where many tiny, bright stars are visible.

Key Points:

• The starry sky is seen at night.

• It looks dark with many bright, twinkling stars.

• Stars are huge, glowing balls of gas far away in space.

What is day?

The period of time when a place on Earth is facing the Sun and has daylight.

Key Points:

1. Happens when a part of the Earth faces the Sun.

2. The sky is bright because of sunlight.

3. Plants and animals are usually active during the day.

Definition:

Energy cannot be created or destroyed it can only be changed from one form to another.

Key points:

• Energy cannot be created.

• Energy cannot be destroyed.

• Energy can change from one form to another.

Definition.

Energy changing form is when energy transfers from one type to another without being created or destroyed.

Key points.

• Energy can change from one form to another.

• Energy is never created or destroyed.

• This is called energy transfer.

Definition.

Energy transfer is how energy moves from one object or place to another.

Key Points.

• Energy moves from one place to another this is called energy transfer.

• Energy can change form while moving.

• Energy is never lost, just transferred or transformed.

Definition.

Kinetic energy is the energy that an object possesses due to its motion. Any object that is moving whether fast or slow has kinetic energy, and the amount of kinetic energy depends on how heavy the object is and how fast it is moving.

Key Points.

• Only moving objects have kinetic energy.

• Objects with more speed have more kinetic energy.

• Objects with more mass have more kinetic energy.

Definition.

Thermal energy is the energy an object has because its particles are moving, and it is felt as heat.

How does thermal energy cool things down?

1. A hot object has lots of thermal energy.

2. The air or nearby objects are cooler.

3. Thermal energy moves from hot to cold.

WHAT IS ENERGY?

Energy is the ability to do work or cause change. It makes things move, heat up, light up, make sound, or change shape.

WHY IS ENERGY IMPORTANT?

Without energy:

• Nothing can move.

• No light.

Definition.

Chemical energy is the energy stored in substances that can be released during a chemical reaction.

Where is it stored?

• In food.

• In fuels.

• In batteries.

Definition.

Using energy is when energy is used to make something move, work, change, or happen.

Key points.

1. Using energy makes things move, work, or change.

2. Energy comes from food, fuel, electricity, sun, wind, and water.

3. Renewable energy never runs out.

Definition.

The pattern of falling is the regular way in which objects move downward under the influence of gravity, usually speeding up at first and sometimes reaching a constant speed due to air resistance.

Key points.

• Falling starts when gravity pulls an object down.

• The longer it falls, the faster it goes.

• Gravity pulls equally on all objects.

Definition.

Air resistance is the force of air pushing against a moving object.

How it works.

• When an object moves, it hits air particles.

• The air pushes back against the object.

• This push opposes motion.

Definition.

Friction is a force that opposes the motion of two surfaces that are in contact with each other.

Types of friction.

• Static friction – keeps an object from moving.

• Sliding friction – slows things sliding.

• Rolling friction – slows rolling objects.

What is weight?

Weight is the pulling force of gravity on an object.

• Gravity pulls everything towards the Earth

• That pulling force is called weight

Key points

• Weight depends on gravity

What is a force?

A force is a push or a pull that can move something, stop it, or change its shape.

Big Forces.

Big forces are strong pushes or pulls.

Examples:

• A car engine pushing a car forward.

What is a force?

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

What is a Force Arrow?

A force arrow is a diagram arrow used to show a force acting on an object.

It shows:

• where the force acts

did textbook

Definition:

Electricity is a type of energy caused by the movement of tiny particles called electrons.

Examples:

1. When you switch on a bulb, electricity makes it glow.

2. A fan spins because electricity powers its motor.

3. Televisions and computers work using electricity.

Definition 

Force is a push or pull on an object that can make it move, stop, or change direction.

Example

Pushing a door, pulling a rope, or kicking a ball are all examples of force.

Definition

An electromagnet is a magnet that works only when electricity flows through it

Examples

1. Electric bell

2. Fan motor

3. Speakers

Definition

Gravity is a natural force that pulls all objects toward each other

Examples

1. An apple falling from a tree

2. people staying on the ground instead of floating away

3. Rain drops falling from the sky

Definition

Thermal expansion is when a material becomes bigger on heating and smaller on cooling.

Examples

1. Bridges have small gaps so they can expand in heat.

2. Railway tracks have gaps to stop bending in hot weather.

3. Jar lids loosen when heated because the metal expands.

• Surface tension is like thin skin on liquid.

• It is caused by molecules pulling each other.

• Molecules inside are pulled in all directions.

• Molecules on the surface are pulled inward.

• This makes the surface tight.

• Small insects can walk on water.