Describe how electromagnetic waves can be refracted at boundaries.

Refraction occurs when an electromagnetic wave changes speed as it enters a different medium, causing a change in direction unless it travels along the normal. Visible light refracting through glass is the clearest GCSE example. The answer should mention a boundary, a speed change and a direction change. This separates refraction from reflection at a surface and from absorption, where the material takes in the wave energy. Within the subtopic Properties of electromagnetic waves in Electromagnetic waves, the explanation is anchored to electromagnetic wave and uses those terms in the approved AQA GCSE Physics Waves context.