Science
noun
The study of science is plainly known as science.
かがく
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
それは科学の本ですよ。
It's a science book.
大人でも科学をきちんと分かってる人は少ない。
There are not many adults who have a proper understanding of science.
次回の科学のクラスまでに、川に行って下さい。
Please go to a river by the next science class.