Here is an idea I got from a colleague of mine recently for a novel way of getting your students to plan a lab investigation. It is a model that could be rolled back and used in a variety of labs and it is very straightforward to do.
Essentially, you give the students a task (for example, testing for halides) and then give the students a framework in which they can plan their own personal investigation. For example, you give them the names of some possible reagents, you give them some safety information, pull out some possible apparatus to use and so one.
Then, the students plan the lab. They need to include full details of quantities, apparatus and reagents in their methods. As a teacher, you can go around and support the pupils at this stage, not telling them what to do but more so guiding them. They may need to finish this section for homework.
The next lesson the students get to carry out the lab …… ‘what’s different then?’ I hear you ask. Well, at this point and without warning the students you swap the methods (procedures) around. Student A is given student B’s method.Student B is given student C’s method and so on. The students then get to carry out the lab but at the same time feedback to the student whose lab it is on the quality of the method they were given.
It’s a great way of getting students to realize the importance of clear and coherent instructions, as well as the need to write concisely and accurately. Of course, you need to be fairly confident that the task is not too hazardous or dangerous, so this task may not work for every group you have.
At the end of the day you can bring it full circle and ask the ‘testers’ to edit/amend the procedure they were given.
Again, the choice of lab is important as you may actually wish to focus more on the process of evaluating another piece of work as opposed to the actual chemistry. The first time you carry it out I think it is inevitable that the chemistry focus will be lost. And of course, it keeps your students on their toes.
The types of labs I could see this working with are straightforward, easy labs. For example, testing for gases, testing for ions but it could be expanded to rates of reaction labs as well.
It goes without saying that for any lab you carry out it is the responsibility of you, the class teacher to ensure all the relevant health and safety aspects are covered.
Have you got any interesting or novel ways of carrying out labs? If so, please post your ideas below.