Tuesday, 20 December 2016
In the class, we coverd the stand with card and made individual labels with the names of all the insects. Francisco's knowledge not only includes the name of each of the species, but also the geographical areas they inhabit, the group or orders they belong to and many other physical features.
The collection included a variety of arthropods, like insects, arachnids and myriapods.
In .this project we built a simple solar hot dog cooker for use on a sunny day. This project demonstrates how easy it is to make use of the Sun's energy.
This hot dog cooker uses a reflective parabola. A parabola is a symmetric curve, that resembles the letter `u´. The focus is a point in the parabola, above the vertex, that is, it lies along the axis of symmetry.
If we cover the parabola with a highly reflective material, such as, aluminium foil, it will act as a mirror and reflect the rays of light. The parabola is shaped so that it collects the Sun rays and focuses them at one point, This central point is called the focus. This point accumulates a lot of energy and is the most active point in the parabola. If we place the sausage along the focus, there is enough energy to cook it in a few minutes on a hot day.
Manuel cooked various sausages this way at the Science Fair. He made the solar hot dog cooker by cutting a parabola out of a shoe box. First, he drew the parabola on graph paper using the formula y=ax2 and used it as a template .Then he covered the box with aluminium paper. He used two long scraps of cardboard to build supports for a skewer. He calculated the focus and placed a long wooden skewer at the focal point with a sausaged poked on it and left it in the Sun. Shortly after, the sasauge was perfectly cooked!