When writing sentences for words like this, it's best to hint at the definition without giving it straight out.
In this case, the definition is that of the word refraction, which is the change in direction of a wave due to a change in transmission medium. In simpler terms, the wave (light, sound, etc.) gets bent, because it's going through something else (through air then water, as in the following sentence).
The refraction of the light through the water droplets made a beautiful rainbow in the sky.
