When they are just 3 years old and barely 3 feet tall, but they has enough energy to fuel a turbine -- and then some. There's never a dull moment around them.

Living with a whirlwind of a toddler can be trying, but it's actually a common challenge: Kids this age have lots of physical energy -- and a great sense of curiosity that drives it. The world is very stimulating for 2- and 3-year-olds, and they love to explore. They're also pretty agile, so they can get where they want to go -- sometimes surprisingly quickly.

It's Fun to Run

The reason toddlers love to race around is simple: It feels good. As adults, we forget what it's like to acquire a new skill. “If your world were just starting to open up, would you pass up an opportunity to check it out?" You, however, might not find this stage of childhood quite as enchanting. But toddlers aren't being "bad" or purposely trying to make your life difficult. The 2-year-old who runs off to chase a bird at the park isn't intentionally defying you.

Toddlers don't have the self-control or the cognitive ability to stop doing things they enjoy. What's more, as they begin to realize that they're unique individuals, they are also testing limits. In trying to figure out how the world works, they question ("I wanna pet the dog across the street. Can I make it over there?"), make predictions ("Yep, probably"), and experiment ("Well, I'll try it and find out").