If you have ever been a teacher at any point in your life, you would have realized the importance of keeping your students engaged and on task at all times during the short period every day that you get to spend time teaching them. If you have just 30 minutes per day, you want to maximize the learning by having a structured lesson plan that moves smoothly from Introduction to New Material to Guided Practice and into Independent Practice. And if you have planned for the lecture properly, you would know how much time you want to spend at each stage doing each activity with the kids to ensure that the lesson is completed on time and doesn't spill over onto the next lecture. You may have a clock in your class, but having a countdown timer makes more sense in competitive and group activities. When the kids see the time ticking down, and they rush to try to finish the activity on time, it can give them an adrenalin rush and bring excitement to the activity. I am an engineer by prof...