Inquiry
If we are to encourage students to be inquirers then there should be some inquiry in our teaching, this implies some engagement from the students which isn't always easy at 8 in the morning. There are many types of inquiry based approaches to teaching and we don't have to get into the details of each type but basically they all start with a question.
Why does a solid cylinder roll down a slope faster than a hollow one?
By finding the answer to this question students will learn about the concepts of moment of inertia and rotational KE. The problem is that there are more than one way to explain this result. A student could use torques and angular acceleration of the rolling cylinders instead of KE, this would miss the point that we were trying to make leaving holes in their knowledge. So, to make sure the correct part of the syllabus is covered maybe guided inquiry is best.
First test by experiment to see if this statement is actually true.
Apply what you know about the conservation of energy to derive an equation for the time taken for the cylinders to roll down the slope.
Read page 433 - 434 to find out about rotational KE.
Follow the same procedure on page 434 to derive an equation for the final velocity of a hollow and solid cylinder.
Measure the final velocity for your cylinders rolling down a slope to see if they agree with predicted.
Use Algodoo to simulate the situation.
Try to explain the difference between practice and theory.
These guidelines don't give the game away but do make sure that the student will cover he relevant part of the syllabus.
It would be rather time consuming to deal with the whole syllabus in this way so it is probably best to give some introductory lectures on the basics of rotational mechanics before launching into an inquiry.
Practical work
At times a much more open approach is possible, this is certainly the case when it comes to the investigation. The whole of the practical programme can in fact be seen as inquiry based learning, starting with well structured worksheets that help students to gain the skills necessary ending with open ended investigations.
At the beginning of the course the student worksheets contain a lot of help so that they can learn to use Excel and loggerPro to manipulate data and draw graphs, later in the course I remove a lot of the scaffold assuming that students now know what they are doing. I could take away the help much earlier for a lot of my students but I leave it in for those that need it. I think it is OK to sometime give too much help, a student who doesn't need it will simply skip over it.
I sometimes put it in a hidden box to make it easier to skip.
Practicals are often used to reinforce theory, an alternative approach is to do the practical or maybe part of it before the theory. After doing the theory of the simple pendulum my students would conduct an experiment to measure the acceleration due to gravity. An alternative approach could be to take the measurements first so students are familiar with the way a pendulum moves before introducing the theory and then analysing the data. The theory could be taught to the whole class as a lecture or through a worksheet with leading questions. I have never tried this approach but intend to give it a go in the future. I do think it is important that theory taught away from the board is best done through a series of questions rather than simply reading in the book where it is too easy to skip to the final equation which can be used without understanding it. I intend to experiment with online solutions to this.
Problem solving
Problem solving is another example of inquiry based teaching although not all problems would encourage this.
A submerged ball of negligible mass is attached to the bottom of a swimming pool by two strings. The volume of the ball is 5000 cm3. Calculate the tension in each string.
This problem simply requires the student to apply knowledge learnt previously so doesn't really promote inquiry however if the student hasn't quite got the idea of taking components then they will have to look it up in their text book, maybe find some supplementary material on the internet, or look for similar problems with solutions. I hide the solutions until students have hd time to try for themselves.
Demonstrations
A demo can be used to set up an inquiry leading to introduction of new concepts and theory.
To introduce projectiles I video a ball being thrown across the lab. This is quickly analysed to show the parabolic trajectory. Why is the trajectory parabolic? The rest of the lesson proceeds to answer this question. Next lesson students do their own analysis extending it to flying balloons where air resistance is a factor.
Sometimes a video clip or a simulation could be the start to an inquiry.
This clip of water waves is a good way of introducing reflection, refraction, diffraction and interference. How can we model these properties of a wave.
The start of every lesson could start with a question;
- How do we measure quantities in physics?
- How can we calculate how far a body has travelled if it is accelerating?
- What is the relationship between Force and acceleration?
We are of course answering these sort of questions all the time but we don't always ask the question. More often than not I tend to launch into the definition of quantities and statements of laws without really putting them into context. In my lesson plans, that are accessible to my students, I list the aims of each lesson, my students find this useful so they can see what it was that they were supposed to have learnt.