I don’t know what kind of response you want to be written but here are some examples if you are trying to recommend or not recommend your science class to a friend:
Positive View:
Dear (Friend),
My science course is really interesting!
You would not believe the topics we are going to learn this year! We are going to learn about the (topic), (topic), and (topic)! Not only that, did you know that (fun fact)? This science course is probably one of the best classes I ever taken! You should take one of these classes if you are also interested in it.
From your friend, (Name)
Negative View:
Dear (Friend),
My science course is not as interesting and exciting as I thought.. It doesn’t have topics about (topic), (topic), and (topic)... I recommend that you don’t take this course. It really is bad. There is not much to be learned here. But if you really want to join the course, I won’t stop you. After all, that is what you wanted. But I will give good luck to you since you might need it. Don’t say that I didn’t warn you.
From your friend, (Name)
Neutral View:
Dear (Friend),
The science course I’m taking is actually not that bad. It have topics that I don’t really understand but I guess I will just learn it along the school year. If you want to know what kind of topics, the topics they are (topic), (topic), and (topic). They seem hard but if I read from a textbook, I start to understand a bit. Though I wouldn’t recommend it to others, it actually have very interesting knowledge to know about. If you want to join, then join.
From your friend, (Name)