Have you heard of tinker trays? They are so much fun. Basically, you give your kids a tray full of, well, stuff and let them play. Tinker trays encourage creativity and are a great way to add some variety to your structured play. They can do so much more than that though. Tinker trays are perfect for STEM exploration. To add an extra level of fun I like to put a little mystery into it. Mystery tinker bags are always a hit in our house. They are perfect for toddlers and older kids, encourage creative thinking, and work on basic STEM skills. Making them a mystery adds to the challenge and excitement of the activity. Your kids never know what they are going to get in the bags! Here is how you can make mystery tinker bags and explore creative STEM fun.