Energy Transformations — Reading Comprehension

Energy is present everywhere, powering every action and process on Earth. When a car speeds down the highway, a flashlight lights up a dark room, or a plant grows in sunlight, energy is changing from one form to another. These changes, called energy transformations, drive the systems we rely on daily. Understanding how and why energy changes form is essential for explaining the workings of both natural and technological systems.

How Energy Changes Form
Energy can exist in multiple forms: chemical energy (stored in fuels and food), kinetic energy (energy of motion), thermal energy (heat), electrical energy, and light energy. When energy is transformed, it moves from one type to another through a series of steps. For example, in a car engine, gasoline holds chemical energy. This energy is released during combustion, producing thermal energy, which then pushes pistons to generate kinetic energy—the car's movement. Not all the energy becomes motion; some is lost as heat and sound, illustrating that transformations are not 100% efficient. In fact, about 70% of the chemical energy in gasoline is lost as heat.

Examples of Energy Transformations
Energy transformations are everywhere. In a flashlight, chemical energy in the battery is first changed into electrical energy when the circuit is completed. The bulb then transforms electrical energy into light energy, which we see, and thermal energy, which we can feel if the bulb gets warm. In plants, photosynthesis captures light energy from the Sun and transforms it into chemical energy stored in glucose molecules. When you eat food, your body breaks down these molecules to release chemical energy, which is then transformed into thermal energy (to keep you warm) and kinetic energy (to move your muscles).

Energy Chains and Systems
These transformations can be represented as energy chains. For example: Car: chemical → thermal → kinetic; Flashlight: chemical → electrical → light (+ thermal); Photosynthesis: light → chemical; Eating: chemical → kinetic + thermal. In each system, energy is conserved, meaning the total amount does not change, but the usefulness or availability of energy decreases, often as heat. Understanding these chains helps us design more efficient technologies and manage resources wisely. For example, improving how engines convert fuel to motion can reduce pollution and save energy.

Energy transformations also connect to bigger scientific ideas. They explain why we need to eat, how plants grow, and why machines get hot when they work. Scientists study these processes using experiments, measurements, and computer models to develop new materials, renewable energy sources, and sustainable solutions for the future.

Interesting Fact:
Every time energy changes form, some is lost as heat—this is why machines and even our own bodies can never be perfectly efficient!

What is an energy transformation?

Which form of energy is stored in gasoline?

During photosynthesis, plants transform which type of energy into chemical energy?

According to the passage, what percentage of chemical energy in gasoline is typically lost as heat?

What does it mean when energy is 'conserved' in a system?

What is the main reason machines and our bodies are not perfectly efficient?

In a flashlight, which form of energy is NOT involved in the transformation chain?

How can understanding energy transformations help us in society?

True or False: Energy can be created or destroyed during transformations.

True or False: The energy we get from food is first chemical energy.