You’ve seen people who balance rocks in a cool way in nature - it's your turn! For this challenge, make a sculpture of items carefully balanced - play around with the physics of gravity and friction...just don't use tape or glue. You can balance toys or sports equipment or things in nature in an interesting way. It could also be hanging something like a branch or ruler from a string in the middle and adding cool objects to each side to keep it balanced. And maybe even knock your sculpture down at the end to prove that it's only held up by physics!

As always, be safe and get a parent's permission before building. Once you've filmed it, work with your parents to share it with us!

Campers stay busy this summer with five different build challenges Mark Rober issues in camp videos. Mark Rober picks a winner for each camp challenge—they'll win a prize pack. At the end of summer, one lucky winner wins the grand prize: a Platinum Ticket to CrunchLabs and a spot in the final video with Mark.

Campers, here's how it works.

Step 1 Build: Build the challenge project.

Step 2 Show: Make a video or take a photo showing your project to enter the contest.

Step 3 Enter: Enter using the form below for a chance to win the challenge contest.