It takes talent to keep a hula hoop going round and round, especially with gravity always working to pull everything down. But what keeps the hula hoop up and twirling?
It's friction-the force that is created when two things rub against each other! In this case, the way the hula hoop hits your body while it is twirling causes the friction. and when the force of the friction you create is the same as the force of gravity, the hula hoop keeps twirling!
Celebrate World hula Hoop Day this year on October 5, 2013.