I want to start talking about this topic mentioning an experiment that was done a few years ago in Germany. To be precise we are in the Tubingen University where a group of experts started an experiment quite particular.
They started creating a team of eleven volunteers, and these people during the 30 days of the experiment, were subjected to different sound stimuli. They were divided in groups:
The first group was the one of those who had to listen, while they were sleeping, to music characterized by slow waves. The doctors noticed that this group, in the morning, was the one which remembered in the best way the words that have been given the night before to the volunteers. The motivation that was behind these results was that the “sleepy waves” produced by the brain of the patients had the same frequency of the music that they were listening.
In fact, to confirm this thesis was the results that obtained the second group. They were obligated to listen to music that had different waves than the waves that their brains produced, and this caused a worsen of the results among the patients.
Maybe for some of you can be a bit difficult understanding this experiment, and I don’t blame anyone because objectively this is a difficult topic, so now I will try to create more clearness.
We can start speaking about “slow waves”. Every animal (also the human is included) when arrives the time of sleeping goes through different phases. To make it easy, these phases are distinguished one from the other from the “depth” of sleeping.
The phase that we are interested in, is the third one, the “SWS” . This one is the deepest, and is reach when the person is totally relaxed, in fact if we observe the body we can see that all the movement of the muscles are really slow or even absent.
When we sleep also our brain is relaxed, but unlike lot of people think, during this phase our brain produces much more waves/frequencies that it normally produces (that are essentially for the formation of the thinking).
Knowing this, we can go back to the experiment that I explained before. The doctors in the last years were able to find a melody that had the exact same frequencies that the brain produced during this phase. All these discoveries were able to bring the experts at the experiment at the beginning.
They decided to do the experiment to check if the music can really help remembering different types of information, the results were amazing and for sure helped revealing another small mystery of the brain.
The amazing thing is that now if you want, you can do the same experiment at home, in fact it is really easy to find on YouTube a video with the sleep frequencies. Maybe (and I really hope so) this small trick can help you in a test at school.

Sources
https://www.levinemusic.org/about/news/how-music-affects-memory-and-concentration/
https://www.abc.net.au/listen/classic/read-and-watch/music-reads/the-intricate-relationship-between-music-and-memory/103471516