A two, three or four-year-old brings plenty of joy and excitement but not always the best sense of judgement, especially when playing at the park. With more kids, and their parents, heading to local parks this time of the year, one common accident can hurt a child in less than a second.

With breeze off the Chippewa, shade from the sun and only seven parking spaces, Owen Park fills up fast once the ground thaws.

"This is a popular park for preschoolers," said Dave Bohlinger, Eau Claire Park Maintenance Supervisor.

Children pack up the place most mornings and some decide that today is the day to become a big girl by bypassing easy stairs for a hard climb.

"I definitely don't bring a book because she does try to climb," said Jason Emerson, parent of 2-year-old Siena.

"Kids in that toddler stage almost seem to be built for it," said Dr. Kirk Dahl, who has worked emergency rooms in Eau Claire for more than two decades. "They can handle any fall as long as it isn't too high."

Keeping your pre-schoolers and toddlers safe should be easy, just by spotting them to keep this activity from becoming an unplanned monkey bar exercise. But what if you're juggling two or three kids or one of them just likes hanging out on the edge?

"There are some openings here but you have to account for them," said parent Jennifer McCauley.

On this day, we talked, informally, with the other moms and dads out here and half admitted to having to take their child to the ER for a playground fall. None of them walked to go on camera and talk about it.

So, just how quickly can it happen? A fall that turns a morning of fun into a morning of fright.

We set a weighted Dora the Explorer doll on an open platform, exactly five feet from the ground for a time experiment.

8/10 of a second. That's how long it takes a weighted object like Dora to hit the ground. That's how long it would take to change your toddler's day.

The U.S. Consumer Product Safety Commission estimates about 100,000 playground falls are treated, each year, in emergency rooms, with head injuries bearing the most concern.

Only about fifteen die each year in the U.S. from playground equipment injuries but when your little one falls, it's natural to fear the worst.

"Parents often feel responsible," Dr. Dahl said, "but you're being responsible by letting them play out here. I've had my kids in this ER several times."

Wednesday night on NewsCenter 13 at Ten, we'll go inside the safety features seen on today's public playgrounds, why some equipment is built to encourage falls but only to spots with softer landings.