How can you, as a student, be sure that you really understand the basic concepts of science? How can you be sure that the ideas that have been "taught" have actually been "learned"?
One answer to that question is problem solving. For many principles in science, chemistry, physics and biology the test of understanding is the ability to solve problems related to that principle. If you can problem solve, then you can say with some assurance, that you have mastered the related concepts.
But the ability to solve problems - and the ability to understand scientific concepts - does not come easily. Only through continual practice with many problems do most of us develop skills in many of the simple scientific concepts.
Each section of the exercises will have
1) at least two solved problems to use as examples with a brief description of the skill.
2) three pages of practice problems each divided into three levels of difficulty: Simple (Level 1), Moderate (level 2), and Advanced (Level 3).
Good luck and have fun. These are meant to be a challenge, not a frustration!