Art and science collide in this rainbow ice tunnel DIY project for you and your kids. This activity can keep kids busy and entertained for at least an hour. Check out some cool pictures of how these ice tunnels can turn out! All you’ll need are some liquid watercolors, table salt, medicine droppers, plastic tubs, and a muffin tin. You’ll have to freeze the ice blocks overnight before you start. Read on to see how they are made!