What are the simple tricks to get and maintain attention of students in a science class?

to teach students the way you want, you have to engage the students among themselves, by asking intresting questions keeping into account, thier interest, capability and preferences. if a student answers wrongly never ever tell the whole class that s/he has answered wrongly, but ask the same question from the other student and ASK IF THE FIRST STUDENT`S ANSWER IS CORRECT?!  AND WHAT THE SECOND STUDENT THINKS ABOUT IT, naturally, students have great jealousy among themselves, this way they try to revive thier inner abilities (but infact it is thier wish to defeat and impress the students of thier age)

to get attention of students in class give examples which are related to their life. use terms which relates with them. more you try to make topic familiar to students more they will be attracted towards the class.