When a ray of light goes through a sheet of glass, it is refracted. In certain circumstances there can be total reflection.

Un espejo esférico es una superficie reflectante que podría formarse como una sección de una esfera separada del resto por un plano. Hay dos tipos de espejos esféricos: los cóncavos y los convexos.

Una lente esférica es un cuerpo transparente formado por dos caras esféricas. Esta escena permite ver los tipos de lentes que existen.

The educational resource shows a visual about tides: the effect of the gravitational force of the moon and the sun on the earth can be seen in the tides.

The educational resource shows information about the concept tidal energy and its advantages and its disadvantages.

Suitable lenses, correctly combined, as in the following visual can help you to understand how a telescope works.

Instantaneous acceleration is a vector. It can be broken down into two perpendicular vectors such that their sum is instantaneous acceleration.

Heisenberg showed that measuring the magnitude of a quantum particle altered its state, so that another magnitude could not be measured simultaneously

The educational resource shows a visual about the variable intensity of gravity: the intensity of gravity, g, is not a true constant, as it changes with altitude.

The educational resource shows an interactive animation about the thermal equilibrium: when two substances at different temperatures are in contact, they exchange a certain amount of energy. One's temperature increases, and the other's decreaeses. In the end, they both reach the same temperature, which is known as equilibrium temperature.

The educational resource shows information about the concept of thermal energy: thermal energy is due to the movement of the particles which make up matter.

The educational resource shows an interactive animation about the thermometer: the fact that mercury and alcohol expand when the temperature increases is used to construct thermometers.

The cathode ray tube gave rise to an application which had an application that became very popular in the second half of the twentieth century: television.

The educational resource shows a visual about the solar system: What is at the centre, the sun or the earth? This question has been asked since the beginnings of humanity. The answer is found in the different models of the solar system.

The educational resource shows a visual: it is a simulation of the solar system, you can select the planet you want to see and also vary the plane of the orbits.

The educational resource shows a visual about the solar system: the solar system is formed by the sun and all the astronomical bodies which orbit around it.

The educational resource shows a visual about the intensity of the electric field: a body's electric charge alters the space which surrounds it. The magnitude which measures this alteration at a determined point is the intensity of the electric field at this point. It is defined as the force exerted on the unit of positive charge situated at this point.

The educational resource shows a visual about the principle of superposition: when we talk about systems with more than two bodies, we have to bear in mind the Principle of superposition of forces: the force exerted by one body on another is independent of that exerted by the rest.

The educational resource shows a visual about the shape of galaxies: what causes the variety of shapes among galaxies? Some are spiral galaxies, others are elliptical or spherical.

The educational resource shows a visual about the planets: in addition to our planet, there are another eight planets travelling around the sun.