What are invisibility cloaks made of, and when can we buy them in gift shops? That's right, invisibility cloaks are not just for wizards anymore. We get into the very real science of invisibility with Dr. Andrea Alu. Dr. Alu is one of the leading scientists working on "cloaking." We learn how scientists are playing with the laws of physics and optics to turn fantasy into scientific reality. Have a question for Tumble? Send us a recording with your name, age, question, what you think the answer is, and how scientists might find out. Email it to email@example.com! If you love Tumble, support us by writing a review on iTunes or donating on our website. For more about Kids Listen, a new awesome organization for kids podcasts, visit kidslisten.org.