Using Your Eclipse Viewer
With the sun behind you, position your box so that the side with the hole and aluminum foil points back at the sun. You may need to tilt and move the box around to get things lined up, but you should see a small image of the sun inside your box when looking in the hole. This is normally round, but during an eclipse you will notice a crescent shape.
And there you go! Eclipse viewer magic. Special thanks to the University of California San Diego for sharing this activity with us. You can learn more about the upcoming eclipse in October by visiting the American Astronomical Society Eclipse site.*Note: Accessing this link means you are now leaving the Holland America Line website and navigating to a third-party website that is not owned, operated, or controlled by Holland America Line or any of its affiliates.