Great resource for design challenges and engineering projects! This website is my new best friend! Not only does it have some amazing Engineering Challenges, but it is sortable by age, content, and duration! Oh, man! I have tried many of these with students and will dish more on each one as I can! Check out DiscoverE!
Button batteries can post a risk when ingested. They can be a choking hazard, but also can get lodged in a child's esophagus and cause blockage and burning! I have not been able to find any age recommendations by the AAP, NSC or NCPC. It seems the greatest risk is posed to children under 6. Please ensure safe practices when using batteries with children!