Watermelon

Nuno Oliveira, 12ºD
Escola Secundária de Loulé

The watermelon is the succulent fruit Citrullus lanatus (formerly called C. vulgaris), of the gourd family, native from tropical Africa and cultivated on every continent except Antarctica. It has been cultivated since ancient times in the Mediterranean region, Egypt and India. The vines are annual and spread across the ground with branched tendrils, deeply cut leaves, and light-yellow flowers. Each vine bears 2–15 large, reddish, white, or yellow, sweet, very juicy fruits with flat black seeds (external color is black).

Varieties differ in flesh color, shape, and rind thickness. The rind may be preserved as a pickle.

Watermelon. Scientific Name: Citrullus lanatus
Nutritional Information: One slice of watermelon (480 g) contains 152 calories, 3 g protein, 34.6 g carbohydrates, 2.4 g fiber, 560 mg potassium, 176 mg vitamin A (RE), 47 mg vitamin C, 0.3 mg thiamin, 0.1 mg riboflavin, and 0.96 mg niacin.

Pharmacological Activity: Watermelon is rich in lycopene, glutathione and vitamin C. It has great activity against cancers and some antibacterial, anticoagulant activity.
Eating Tips: Choose watermelon with a deep red color.

Energy in our way of living

By Nuno Oliveira, 12ºD
Escola Secundária de Loulé

Energy is an important factor on our daily life. In everything that we do, there are always energy exchanges between systems. The simple fact the we breath or even think, is responsible for a large amount of processing in these exchanges.

Rational use of energy in houses and schools is a major concern in our time. Since most electric power is still produced in thermoelectric power plants using fossil fuels, waist of electric energy will be a way of accelerating fossil fuel consumption and also an extra contribution to global warming, since the fossil fuels that are burned to produce electric energy produce carbon dioxide, is the major atmospheric component that we can consider responsible for global warming. Nuclear Power Plants are still not a solution because, besides the security problems, fission depends on uranium and uranium is not renewable.

A nuclear power plant close to Berlin.

In our houses, schools and cars, energy is always present.
We can think of several ways to optimize energy consumptions in our daily life.
For instance in house construction there are several things that have to be thought that can reduce energy consumption.
The house should be prepared in order to achieve the higher thermal insulation that is possible. This can be done by using double walls, and double glass windows. In the first case the low thermal conductivity of air or a polystyrene layer between the two wall layers can help to prevent easy energy transfer in or out of the house. In double glass windows this is guaranteed by the air layer between the two glasses.

A solar collector for water heating

We can also use local energy resources like sunlight to increase energy use efficency.
In our houses, schools and cars, energy is always present.