#hot air balloons

“New seasons entered the blood like oxygen, their songs and ripening fruits filling our lungs and seeping into our bones. Autumn crept up from below, like a rising tide, and a desperate few fled to the sky, hoping to find lingering fragments of summer tucked between the clouds.”

-QuietPineTrees

The fundraiser for the new Quiet Pine Trees book does have an expiration date. If you want to support me as a new author, and help make modern media a little weirder, consider pledging today!

Quiet Pine Trees

My latest review is on ‘Hemisphere’ from the brewery FourPure. You can tell instantly that a lot of time and effort has gone into designing the can artwork so surely the same amount of time must have been invested into crafting the beer? 

A lot of smaller breweries rely on strong marketing and attention grabbing can design in order convince people to make a purchase. Maybe the design work sets a high bar but in this case the taste leaves a bit to be desired. 

One of the most surprising things about air that may not be intuitive is that it is a fluid and like any other fluids exerts a pressure on objects.

Standing on earth with layers of air above us, we are constantly being ‘weighed down’ by a pressure of  ~1atm at all times.

All objects in air are also assisted by a buoyant force that is caused from the pressure  difference between the top and bottom surfaces.

Let’s now consider the hot-air balloon in particular. A force diagram is probably the best way to start:

Therefore we see that in order for the hot air balloon to float, we need to have the buoyant force compensate for the net weight from the balloon, the load on it and the air inside it:

And with a spectacular burner onboard our hot air balloon, we can easily increase the temperature of the air inside the balloon!

That’s pretty much how hot-air balloons work! You increase the temperature of the air inside the balloon to go up, decrease the temperature to go down and skillfully adjust the temperature to hover.

Have a great day!

Questions to ponder:

• When you increase the temperature of air, its density decreases. What do you think happens to all the molecules that were previously inside ? Do they exit the balloon ?
• Different shaped hot-air balloons is a common sight. Do you think that the Buoyant force changes for each shape?
  
• How do you think Helium balloons work ?

cherepashkadrabbles:

Time for Things Like This - Cherepashka - The Silmarillion and other histories of Middle-Earth - J. R. R. Tolkien [Archive of Our O

@officialtolkiensecretsanta gift for @ibrithir-was-here. Wishing you a very festive winter, whatever holiday(s) you celebrate! Have some early developing-relationship fluffy nerdy Silvergifting. I hope you enjoy!