It's a good article, but at the end says:

> Since the development of quantum mechanics, physicists now acknowledge light to be both a particle and a wave.

It's common to explain light like this, but it's wrong. Light in never a particle. Light is never a wave. Light is a weird thing that only QFT can explain using so much Math that is enough to make Math majors cry.

In some experiments, light can be approximated as a particle. (There are a few good examples in the article.) The approximation is much easier than the complete math equation, and it's very accurate, so in those cases you approximate light as a particle and are happier.

In some experiments, light can be approximated as a wave. (There are a few good examples in the article.) The approximation is much easier than the complete math equation, and it's very accurate, so in those cases you approximate light as a wave and you are happier.

But in both cases, they are just approximations.