As a father of 4 kids now ages 19, 21, 23, and 25 I often encouraged curiousity when they were little. I know it can make parents pull their hair out when little Johnny or Suzie gets in to things but this is how they learn and grow.
One common thread amongst highly successful people I've been around is that their parents encouraged them to be curious or didn't punish them if they were as long as it wasn't life threatening.
The key to being successful in life is to get out of your comfort zone and kids naturally get out of their comfort zones but parents oftentimes stop them and over time they will learn to stop being curious.
While my kids are far from perfect I have 2 who attended college and 2 who own businesses...one of which he started as a sophomore in high school.
So, don't look at your child being curious as a negative because it is not.