Experiments and active learning

After learning a lot about light, particles, waves and other wonders of physics through presentations, we had a whole afternoon (Tuesday) dedicated to active learning. Thanks to Prof. Paruch, we had the chance to experience directly how light behaves.

First experiment: lenses and mirrors. Though most of us had already done some similar experiments in high school during science class, it was pretty different with a great physicist next to us, ready to answer all of our questions, even the most strange ones. We had at our disposal an impressive choice of lenses and convex and concave mirrors to play with. One thing we learnt is that light does not always go where we expect it to go. Second, you can make some pretty things with lens and colorful sheets of glass.

The second experiment was more complex and it was not easy to have a full understanding of it right away. It involved a laser (not a powerful one) and some grating. We projected the laser through the grating and observed the pattern it made on the white screen, hoping to fully understand how it worked. After measuring the spacing between the dots, we drew figures to help us make clear what we understood. According to the pattern you get on the screen, you can actually know how the grating is designed. It can be used to find the different planes of crystals or to recognize one from powder as the crystalline structure is preserved.

The last experience was about optic fibers. The main point was to understand how it works and to find some applications of this concept. The functioning of an optic fiber is quite intuitive: the beam of light is bouncing (the accurate term is reflecting, but it is not as funny) within the fiber and thus you get light at the end of the fiber.

A surprising application of this bouncing concept in the animal world is polar bear. Their fur is made, not of glass, but of an organic matter that plays the same role as an optic fiber, bringing light, and thus energy, directly to the skin. As its skin is dark, it absorbs easily the energy and it keeps the polar bear from being cold. They are so lucky!

During that afternoon, I also had a thought for our mice that had just discovered their new houses. We spent an entire afternoon (Monday) designing houses with different kinds of windows and shapes, hoping that they would either love or hate them. Well, we'll see the results at the end of the week...