Have you ever kicked a ball and watched it roll away, pushed a swing and seen it go back and forth, or switched on a light bulb and wondered how it shines? Four important science ideas explain all of these everyday events: force, motion, work and energy.

These four concepts are connected like links in a chain. Force makes things move, motion shows the movement, work happens when objects move because of force, and energy is what makes it all possible. Let’s explore them one by one.

What is Force?

Force is a push or a pull that can change the way an object behaves. Without force, objects at rest stay still, and moving objects keep going at the same speed and direction.

Examples of force in real life include:

• Pushing your school desk from one side of the room to another.
  
• Pulling open a stubborn drawer.
  
• Kicking a football across the field.
  

Forces can also slow things down or stop them. When you ride a bicycle and stop pedalling, the frictional force between the tyres and the road slows you down.

The unit of force is called the Newton (N), named after Sir Isaac Newton, who discovered the laws of motion.

What is Motion?

Motion simply means movement—a change in position over time. If you walk from your classroom to the playground, you are in motion.

There are different kinds of motion:

• Linear motion: Moving in a straight line, like a car driving down a road.
  
• Rotational motion: Spinning, like a fan or the wheels of a bicycle.
  
• Oscillatory motion: Moving back and forth, like a swing in the park or the pendulum of a clock.
  

Force is what causes motion. For example, when you throw a ball up, it moves upward because of the force you applied. But gravity, another force, pulls it back down.

What is Work?

In everyday language, work means effort, like when you say, “I worked hard on my homework.” But in science, work has a specific meaning: work happens only when a force makes an object move in the direction of the force.

For example:

• If you push a box and it slides across the floor, you have done work.
  
• If you push a wall and it doesn’t move, work has not been done, even if you get tired.
  

The formula for work is:

Work = Force x Distance

This means the more force you apply and the further the object moves, the more work happens. The unit of work is the Joule (J).

What is Energy?

Energy is the ability to do work. Without energy, no work can be done, and no motion can happen. Energy exists in many forms:

• Kinetic energy: The energy of moving objects, like a rolling ball or a running child.
  
• Potential energy: Stored energy, like water behind a dam or a stretched rubber band.
  
• Other forms: Heat energy (from fire), light energy (from the sun), electrical energy (from a battery), and chemical energy (from food).
  

A key scientific rule is the Law of Conservation of Energy: energy cannot be created or destroyed; it only changes from one form to another. For example, when you eat food, the chemical energy in the food changes into motion (when you walk or play) and heat (to keep your body warm).

The Connection Between Force, Motion, Work and Energy

Now let’s bring it all together:

• Force causes motion.
  
• When motion happens, work happens.
  
• The ability to do work comes from energy.
  

Think of riding a bicycle: your legs apply force to the pedals, the bicycle goes into motion, work is done as the wheels turn and cover distance, and all of this is possible because of the energy your body gets from food.

That’s why scientists always study force, motion, work and energy together. They are connected and help us understand how the world works.

Explore More Physics Stuff

From pushing open a door to playing football, or even switching on a light bulb, the concepts of force, motion, work and energy are at play in your everyday life. They explain how things move, how work is done, and where the power to do work comes from.

If you can understand these four concepts, you are already building the foundation for more advanced science topics like electricity, mechanics, and even space exploration.

Want to explore these and other exciting STEM concepts in a fun and simple way? Download the uLesson app today or use the web version and start learning science with engaging lessons, videos, and quizzes designed just for you!