Have you ever desired to soar through the sky like a bird? Do you think it would be enjoyable to have a panoramic view from high above? Even though it is unlikely for us to grow wings and fly on our own, we can still experience a bird’s eye view by riding in a hot air balloon.
You may have noticed hot air balloons decorating the sky with vibrant colors and playful designs. But have you ever pondered how they manage to stay afloat?
Hot air balloons fly due to a simple scientific principle: hot air ascends. Hot air is less dense (lighter) than cold air, causing it to rise.
If you reside in a multi-story house, chances are you have already witnessed this principle on a warm summer day. The basement of your house is typically cool, the first floor is comfortable, but as you go upstairs, you will notice that the air becomes warmer. If you venture into the attic, you will find that it contains the warmest air in the house!
The balloon portion of a hot air balloon is referred to as the “envelope.” It is commonly made of nylon. Nylon is the ideal material for hot air balloons because it is lightweight, durable, and less likely to melt when exposed to heat.
A burner is situated beneath the balloon. It utilizes propane fuel to propel the balloon upwards. When the pilot ignites the burner, a jet flame heats the air and directs it into the envelope. As the air inside the envelope heats up, the balloon expands and rises, carrying the attached basket—and anyone inside—along with it.
One cubic foot of air inside the envelope can lift approximately seven grams, which is a very small amount of weight. This is why hot air balloons need to be quite large. In order to lift the weight of a basket and passengers, a significant amount of hot air needs to be contained within the balloon.
You might be wondering why there is a hole at the bottom of the envelope. Shouldn’t it be sealed? Why doesn’t all the air escape?
Hot air is buoyant, meaning it rises and will not fall out of the bottom of the balloon. As long as the air remains heated, it will continue to ascend, propelling the balloon upwards and keeping it afloat. The more air that is inside the balloon, the greater its buoyancy. This allows larger balloons to reach higher altitudes compared to smaller balloons.
When it is time to descend, the pilot opens a valve known as a “parachute valve.” The parachute valve is a vent located at the top of the envelope that allows some of the hot air to escape. This process causes the remaining air to gradually cool, leading the balloon to descend slowly back to the ground.
Try It Out
We hope today’s Wonder of the Day has sparked your interest! Keep soaring high by engaging in one or more of the following activities with a friend or family member:
- Have you ever witnessed the spectacle of numerous hot air balloons filling the skies? If not, you should consider attending a hot air balloon festival. Conduct an online search to find information about any upcoming hot air balloon festivals in your vicinity. You can also visit the website of the Albuquerque International Balloon Fiesta, which hosts one of the world’s largest hot air balloon festivals annually!
- One of the most captivating aspects of hot air balloons is their vibrant colors and intricate designs. Explore the option of designing your own hot air balloon using online tools on your computer. Once you’re satisfied with your creation, you can even print it out. Enjoy the process of crafting a hot air balloon that rivals the beauty of the daytime sky!
- Are you interested in constructing your very own homemade hot air balloon? Give this experiment a try by utilizing a hair dryer. Although your homemade hot air balloon may not have the capability to carry a basket full of people, it can still strive to reach for the skies!
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