This is a very great question to ask that can have multiple answers to it. As a preservice teacher myself, I would say the biggest tip of adivce that I have learned through going to several field experiences is simply help students understand the meaning as to why they are learning something. If students are able to understand the "why", than they will learn and work toward the "how". Helping students understand the meaning of a specific subject area make look a little differen't based on what it is you are teaching about. One way I have seen a teacher bring out the excitment in students is by relating the topic to things that they enjoy in their personal lives. For example, in one unit my teacher was describing what space is and she found a really quality educational video game online about space that all the students loved and enjoyed. As far as motivation goes, I am not sure if you can motivate someone to like science, but rather explain the meaning as to why they are learning something so they can relate with it. Do you have any other good ideas to help breakdown the the meaning of concepts for students that you have come across? I would love to here them! Are their any fun activities that you know that students enjoy in the classroom?