Set a curious kid loose on the internet, and you have a match made in learning heaven. Unfortunately, for every geometry lesson on Khan Academy there are step-by-step instructions for something not just age-inappropriate -- but potentially illegal or dangerous.
While browser settings and parental controls can help keep your kids on appropriate sites, it's nearly impossible to shield them from every risky thing. But most tweens and teens who look up how to make fireworks, for example, are not reckless enough to try it. Try not to freak out if you find them searching for something iffy. That way, you keep the lines of communication open, and you can better help kids to think critically, ethically, and safely about what they find online.
Here are a few examples of the not-so-nice info kids can easily find, plus some conversation starters. (If you're really concerned that your kid's explorations are leading them into dangerous territory, you may need to take more serious action.)
Related: Toys you should avoid buying for your kids
What you can do:
Talk to your kids about your expectations for what they do online, including being safe and using common sense. Then, ask questions that prompt deeper thinking such as:
Is it ethical to teach people how to do risky activities online?
Do you think these lessons are accurate?
Who's responsible if someone gets hurt from attempting online instructions? Only the injured party? The original poster? The website?
What would you do if a friend wanted to do something harmful?
What are the best conditions for conducting experiments?
Just because you can find certain information online, should you look for it?