Touch the Spring
It‘s all done with mirrors.
Touching the spring seems easy, but the image of a spring is made by a big curved concave mirror. Light from a real spring bounces off the mirror to form the image you see. If you shine a flashlight at the image of the spring, the light reflects from the mirror and lights up the real spring. Because the real spring is lit up, it’s reflected image is lit up, too.
Can You Believe Your Eyes?, Touch the Teapot
More to explore
You can see it, but you can’t touch it.
Testing methods for encouraging meaning-making in a science museum