Science subjects such as Physics, Chemistry, Biology can be understood easily if proper audio visuals are used while teaching. Today's classroom sports digital whiteboard and laptops to enable students to grasp subject matter faster. But ultimately, it is the teacher that uses these in order to facilitate learning. So also with Math-Calculus, Geometry, Algebra, Trigonometry can be fun to learn and to solve problems. But, teachers need to make their students understand the fundamental concepts better. What if the student misses a particular class or two? Understanding becomes a little difficult. And some students need extra coaching, but all will benefit if they sit through another session of the same class. Several websites offer a chance for students to pick up extra understanding of these subjects on their own or with their teacher. Some are Free and some are subscription based. Brightstorm.com is a websites offering Free Video-Based Lectures on almost all topics of Science and Maths. Below is a sample.
The Human Reproductive System.