You're asking a very hard question. A lot of this will depend on the motivation itself of the students. Without knowing the students previously, the best you can do is plan for a lot of scenarios and hope one of them fits and works. Also, 25 students is a lot to work with in this context.
I would begin with what you know about the students. They have been learning English for 5 years, are about 13-14 years old, and probably have a decent level of English, if not pretty high. This is a good starting point to work with them and plan out some ideas.
There's one key thing missing: What do you know about their personalities? This is the most important factor with teaching this age group. The class itself will have its own personality. With this age group, you are likely to find one of the following:
1) They might all be moody. I have a group of Jr High students right now that are great kids some days and other days, I dread the next 2 hours with them. A big reason for this has to do with the fact that they go to school all day and then their parents make them come to English class. The more moody they are, the more you expect them to conform, the more disastrous it will become. With a moody class, you have to be very flexible, fluid, and (from what I have seen) have to have a lot of experience to know how to change modes and still guide them somewhere. If they ARE moody, just do your best for your first day.
2) A great, talkative, sharing group. I had one class I miss a lot. They were 7-8 grade and they just wanted to come into my ESL class and talk for 2 hours. This, of course, made it easy on one hand, but I still had to guide us through some of the material or they would never get through it. With classes like this, try to watch your time a little.
3) The quiet class. For this class, I've found it best to keep encouraging simple responses and actually back off on correcting them at first. Let them start by realizing it's ok to take the chance and screw up...you'll still learn something. Eventually, you hear more from others.
4) The quiet class with the one students that talks. With this class, rather than stopping that student, encourage that student to ask questions of others and engage them in the conversation. It's less threatening to talk with another student than it is with a teacher you don't know.
Now...back to the specifics of your lesson. I think you have some good ideas overall. Maybe comparing and contrasting the similarities and differences between the inventors and how they came up with their invention might be a good extension. Creating a comic book about the history of how one of those inventions came about is another one that they might enjoy. (They can work in teams to make it faster and decide who will work with what part). (That might be hard with a 45 minute time restraint).
With concluding the lesson, I think it's more important to have an idea of what you want the students to learn in the lesson first. With my ESL classes, I go in knowing what I hope they learn. If they are reading a story, I know what each class needs. For example, with the stories my students are currently reading, I know I am looking for:
--Level 2: Changes in voices when different characters are talking.
--Level 4: Some excitement or emphasis when the exclamation points is used.
--Level 6: Voice changes (same thing as level 2...they were just never taught it until I started teaching them. UGH!)
I look ahead in the story and see what I'm going to work with them on. It's OK if we don't get through the story since it's not the skill I am working with at the time. I know they can read the whole story in a given time frame. Now I need them to add meaning to the story so we practice that. As a conclusion, I review what I hope to hear from them next time and give them a few samples to read that are not from the text, hoping they do it in the way I taught in class.
Deciding on a conclusion is the same with grammar classes, conversation classes, etc. I want them to be able to understand the key concept of the class and just have a quick time to practice so it's the last thing we did, but not so much so that it tires them out.
I sort of rambled. I hope I helped some.
Oh thanks :)
Well, the problem is that I don't know the class. I will see them for the firs time. My lesson will be graded by other teachers and mentors then. So, what I am missing are some ideas on how to develop this main part of the lesson. I have already decided how I will make an introduction and conclusion but since there are 25 of them I don't know the best way to teach them these 2 texts. That is why I wanted to split them into 6 groups. What do you say about this:
So, 3 groups read the text about the telephone and 3 about the clock. Here is where I need some help( like I've said, there are 7 questions under each text and I don't know how exactly I should incorporate that into the lesson to make it interesting :/ ) I hope I will come up with something.
Matt is a marvelous resource on your post! I might add that although it is difficult to work in groups at first and to have the students spend "time on task" it is rewarding to have the students do what they can. Because you are not familiar with these students, large groups are OUT. Groups of 2, 3, 4 usually work and undoubtedly the class can not be divided so each group is equal. By walking around, observing the students and listening carefully, you will quickly learn both the individual and class "make up." Good luck and trial and error will let you know what truly works. Each group can be very different, and that's the fun!
Sra (aka Mme)