There is a plethora of sites on the internet offering lesson plans to teachers in need of a bit of inspiration and/or assistance. Because there are so many, is seems reasonable that there is a need for them.
The question that arises is “Are there so many things worth learning that can be fitted into one 40 to 60 minute block of time?”
In the “Google Age”, facts and formulae are easily accessed through an almost-infinite range of apps and web pages (for example, http://www.freemaptools.com/area-calculator.htm). The teacher’s task is to help students make connections and think critically about what they learn. The average student is more likely to retain and understand something taught if it is part of a sustained unit of learning, over time, that involves a variety of learning modes and feedback and reflection. “One-off” lessons based around cultural/religious celebrations or fortuitous current events may entertain and motivate students, but, unless they are skilfully crafted with student learning in mind, the enduring learning is probably superficial.
Unit plans that span several weeks and employ a range of activities selected for their learning potential and allied with immediate feedback and on-going reflection facilitate student learning of skills attitudes and knowledge that will sustain them through their lives. When students have the opportunity to collaborate and inquire deeply into important concepts and questions, then the learning is deeper and longer-lasting.
Teachers still need a “sketch” of lessons to assist with time management and organisation. However, the need for the teacher to address the whole class at the beginning and end of lessons (and during) is minimised in student-centred classrooms – Once a unit is underway, students usually know what they have to do, leaving the teacher free to move about the room and monitor and support individual groups, who may well be doing different things or the same thing at different levels and rates. This is very difficult to put down on an A-4 sheet of paper.