Explanation Text

XII IPA 2

Adam Maulana Bramantya Krisna Kamel Yusuf M. Ridho Prasetyo

How Does a Hot Air Ballon Fly?

Explanation Text

DefinitionExplanation is a text which tells processes relating to forming of natural, social, scientific and cultural phenomena. Explanation text is to say ‘why’ and ‘how’ of the forming of the phenomena. It is often found in science, geography and history text books.

Generic Structure

Featuring generic participant; sun, rain, etc Using chronological connection; to begin with, next, etc Using passive voice pattern Using simple present tense

Language Feature

General statement; stating the phenomenon issues which are to be explained

Sequenced explanation; stating a series of steps which explain the phenomena.

Have You Ever Wondered... How does a hot air balloon fly? Why are hot air balloons so big? How do hot air balloons hold air

inside when there's a hole at the bottom of them?

Have you ever wanted to fly like a bird and soar through the sky? Do you think it would be fun to glide high above, seeing everything from the top down? Even though we're unlikely to grow wings and fly on our own, we can still get a bird's eye view of things by hopping in a hot air balloon. Hot air balloons fly because of a very simple scientific principle: hot air rises. Hot air is lighter (less dense) than cold air, which means it rises.

General Statement

If you live in a multi-story home, you have probably already experienced this principle on a warm summer day. The basement of your home will typically be quite cool, and the first floor may be quite comfortable. If you go upstairs, though, you will notice the air is much warmer. If you climb into the attic, you'll find it holds the hottest air in the house!

The balloon part of a hot air balloon is called the “envelope." It is typically made of nylon. Nylon is the perfect hot air balloon material, because it is lightweight, strong, and it will not melt as easily as other materials when heat is applied.

Sequence of Explanation

A burner is positioned below the balloon. It uses propane fuel to send the balloon up-up-and-away. When the pilot lights the burner, a jet flame heats the air and directs it into the envelope. As the air within the envelope heats, the balloon begins to expand and rise, taking the attached basket—and anyone inside—with it.

One cubic foot of air inside the envelope can lift about seven grams, which is only a tiny amount of weight. This is why hot air balloons have to be so massive. In order to lift the weight of a basket and passengers, it needs to capture a lot of hot air.

Sequence of Explanation

Hot air is buoyant, which means it rises and thus won't fall out of the bottom of the balloon. As long as the air stays heated, it will continue to rise, pushing the balloon upward and keeping it afloat. The more air inside the balloon, the greater its buoyancy. This means bigger balloons can go higher than small balloons.

Sequence of Explanation

When it's time to come back down, the pilot releases a valve called a “parachute valve." The parachute valve is a vent in the top of the envelope that allows some of the hot air to escape. This also causes the remaining air to begin gradually cooling, and the balloon slowly sinks back toward Earth.

Closing

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