Energy Conversion – JSS1 Intermediate Science Lesson Note (Third Term)

WHAT IS ENERGY CONVERSION?

In our last lesson, we learned that energy has many forms, like Heat, Light, and Sound. One of the most amazing rules in Science is that energy cannot be created or destroyed.

Wait, if we cannot make energy, where does it come from? The answer is Conversion.

The Meaning of Energy Conversion

Energy conversion (or transformation) is the process of changing energy from one form to another.

Think of a “Point A” and a “Point B.” For a machine or a human to work, energy must move from Point A (the source) and change into Point B (the result).

COMMON EXAMPLES (AT HOME)

We see energy conversion every single day in our houses. Here are some simple examples:

1. Chemical to Heat and Light

When you strike a matchstick or turn on your gas cooker:

• The match head or the gas has Chemical Energy stored in it.
• When it burns, that energy changes into Heat (to cook) and Light (the flame you see).

2. Electrical to Light and Sound

When you turn on your Television:

• Electrical Energy comes from the socket.
• The TV converts it into Light Energy (the pictures on the screen) and Sound Energy (the music or voices you hear).

3. Electrical to Heat

Think about an Electric Iron or a Water Heater:

• You plug it in (Electrical Energy).
• The coil inside gets very hot (Heat Energy). This allows you to straighten your clothes.

ENERGY CONVERSION IN LIVING THINGS

It’s not just machines that convert energy; your body is a master at it!

1. Chemical to Mechanical (Movement)

When you eat a bowl of rice or yams:

• The food contains Chemical Energy.
• As you run, walk, or play football, your muscles change that food energy into Mechanical (Kinetic) Energy.

2. Solar to Chemical

This happens in plants during Photosynthesis:

• The green leaves catch Solar (Light) Energy from the sun.
• They convert it into Chemical Energy stored as food in the leaves, roots, or fruits.

3. Chemical to Sound

When you use the energy from your food to shout or sing:

• Your body takes Chemical Energy and uses your vocal cords to turn it into Sound Energy.

SUMMARY AND QUICK TEST

Energy Conversion Table

Class Activity

Let’s see if you can trace the path! Fill in the missing gaps:

1. A car engine: Chemical (Petrol) → __________ (Movement).
2. A ringing school bell: Mechanical (shaking it) → __________ (Noise).
3. A solar calculator: Light (Sun) → __________ (Power).

Revision Questions

1. What does the “Law of Conservation of Energy” say about creating energy?
2. Mention two devices at home that convert Electrical energy to Heat energy.
3. Which form of energy is stored in a dry cell battery?
4. Why do your hands feel warm when you rub them together? (What is the energy conversion?)

Homework

Go to your kitchen. Find three appliances. For each one, write down the energy it takes in and the energy it gives out.

• Example: Blender — Takes in Electrical, gives out Mechanical and Sound.