A Balloon that Floats at an Angle

Let's take a look!

Watch the video on YouTube.

What kind of experiment is this?

Experimental procedure and explanation:

• Take a balloon and a dryer
  [Tip] A 45-cm diameter balloon is most stable and best suited for this experiment.
• First, lift the balloon vertically. The point to be noted here is to not move the dryer around. There is no need to move the dryer around for balancing the balloon.
• Next, start tilting the dryer, little by little. The balloon levitates even when the dryer is blowing air at an angle.
• When you are blowing air vertically upwards, the balloon levitates because of drag (air resistance).
• When the dryer is tilted, the airflow is deflected along the balloon (Coanda effect), and there is a force acting on the air that is perpendicular to the direction of the flow (lift). Drag is also acting on the balloon and the resultant force is in equilibrium with the gravitational force.

[Keywords]	Coanda effect, momentum theory
[Reference]	“The Wonders of Flow,” Japan Society of Mechanical Engineering, Koudansha Blue Backs, pp. 128-133