“Q. Could you pick up a dollar bill with a magnet? —B. Gates A. A large electromagnet would pick up a U.S. dollar— though not all currencies— because it is printed with magnetic ink, says James Livingston, author of Driving Force: The Natural Magic of Magnets. You can prove this by hanging the bill freely from a corner and watching it flutter in midair as you pass a magnet nearby. For a more dramatic demo, pour 200 ml of water into a blender, crumple up a dollar bill and toss it in, suggest David Brooks of the University of Nebraska-Lincoln and Robert Becker of Kirkwood High School in Kirkwood, Missouri. Blend for 3-4 minutes while holding a strong magnet to the outside of the glass. When you remove the magnet, see the black ink spot gathered there! “A white plastic spoon behind the spot displays the dark color,” says Brooks. For you teachers, your students will be amazed how much iron is in a single bill, says Becker. But a word of caution: You’re destroying legal tender, so remind the class, it’s all in the name of science. Send Strange questions to brothers Bill and Rich at [email protected]”
