How does your smartphone contact others?
Smartphones have been around for a while now, but they’re still pretty amazing! You call someone and they can hear exactly what you say, even if they’re on the other side of the world. How is that even possible? And how can you then hear the other person’s reply? Somehow, mobile phones are able to send all that information through the air. This involves radio waves.
A lot of radio waves
Heinrich Hertz (1857-1894) discovered these radio waves. You can use radio waves to create little packages of spoken text, image and sound. These ‘packaged’ messages are sent and received via the antenna in your smartphone. So when you send someone a text message, you are making a connection via radio waves.