For Class 8 students studying under the Central Board of Secondary Education (CBSE) in India, there are several good reference books for science that can complement the NCERT textbooks and help in understanding concepts better. Here are some widely recommended reference books for Class 8 Science:

1. "Science for Class 8" by Lakhmir Singh and Manjit Kaur:

   • This book provides detailed explanations of science concepts, ample illustrations, and a variety of questions for practice. It is aligned with the CBSE curriculum.

2. "Together with Science" by Rachna Sagar:

   • This reference book includes additional practice questions, exercises, and solved examples to reinforce understanding. It is designed to support the CBSE syllabus.

3. "Science Textbook for Class 8" by NCERT:

   • The NCERT textbooks are the primary source for CBSE students. Ensure that you thoroughly study and understand the content provided in the NCERT Science textbook for Class 8.

4. "Science Exemplar Problems Class 8" by NCERT:

   • This book by NCERT provides additional exemplar problems and solutions, offering more practice for students aiming to strengthen their problem-solving skills.

5. "Full Marks Guide of Science for Class 8" by Full Marks Publications:

   • This guidebook includes chapter-wise summaries, important questions, and solutions. It is designed to help students prepare for exams effectively.

6. "MTG Learning Science for Class 8" by MTG Editorial Board:

   • This book includes a variety of questions, including multiple-choice questions (MCQs), short answer questions, and long answer questions, to cater to different learning styles.

Remember that while reference books can be valuable for additional practice and clarification of concepts, it's essential to primarily rely on the NCERT textbooks as they are designed according to the CBSE curriculum. Additionally, consult with your teachers to understand the specific requirements of your school and class.