How can I improve my grades in science classes?

Science is to solve the known problem and find the unknown problem for the next generation scientist to solve. If you do not score perfect in science, as normal human being does, you can identify the problem first. Which part of science class you did the worst? Remember, science is not a abstract field but a practice field, even in theory physics.

First, let me applaud you for wanting to improve. Many students just say "oh, I am not good at that subject," and they never try to get better. But the good news is you are living in the right time period to get the help you need. Even if your textbook is difficult to understand, and even if it seems you are confused about some scientific theories, you are NOT alone. In fact, there are so many wonderful scientists online, and they have websites, articles, videos, etc. You can read their ideas and watch them as they explain the topic to you. There are also TED Talks (you can find them on You Tube) where famous men and women of science discuss areas of science that they care about, often in a very understandable and interesting way. Perhaps there is an aspect of science that interests you: many people today care about climate change, or they care about outer space (Will we find any new planets? Will be find out if there is life on some of the planets were are researching?). If you can start learning from the experts, using the internet to do it, you will undoubtedly find it has a positive impact on your grades.

Also, be sure to take good notes when studying -- with science, you are trying to find out WHY something happened, as well as HOW it happened. So, don't just memorize a theory. Teachers want to know if you understand it. Think about what it means, and think of good examples that would explain it. Knowing how to explain (in your own words) and then apply (show how this could be used in daily life) a scientific theory is another thing that will help boost your grades. See if you can find some online sites that demonstrate certain theories-- showing you how and why a certain chemical reaction occurs, for example. Being able to visualize a scientific theory or concept is one way to better understand it. (And don't be shy about asking for help-- if you are sincerely trying, and can show your teacher that you are making a good effort, most teachers will be willing to give you some guidance. They just want to see that you have made an honest attempt to find the answer yourself. )