Experimenting CLIL: school subjects in English / Science

Travelling among the colours of astronomical phenomena

Hi guys!
Let’s start our journey in the world of colours! They’re an effect of scientific and meteorological phenomena, so we can find them everywhere.
For example, the rainbow is a spectrum of lights that appears when the sun reflects itself on drops of water suspended in the sky after a storm or next to fountains or waterfalls. It looks like  a multicoloured arch, and the sequence of the colours is red, orange, yellow, green, blue, indigo and violet.

But how does it work? Light rays enter a drop, reflect the back of the drop and leave it. On leaving the drop, this light spreads over a 40°-42° angle. Subsequently, white light separates into the 7 different colours so we can see the rainbow.

The most spectacular rainbows can be seen when half of the sky is still dark because of the raining clouds and the observer is in a place where the sky is clear. Other particular rainbows are the moonbows, or night-time rainbow, which can be seen at nights lit by the moon. However, the perception of colours is really low at night, so they mostly seem white.

A rainbow doesn’t actually exist! It only depends on the observer’s location and on the position of the sun. Indeed, only the light reflected by some drops only reaches the observer’s eye and it creates the rainbow for that observer.

We can find them in pictures, novels or poems, too. For example, Virginia Woolf used the rainbow as the metaphor for life transience and of man’s mortality.

Do you remember? The rainbow is also linked to leprechauns, the goblins typical of Irish mythology; it is said that they’re very rich and that they have hidden many treasures in a secret place: according to the legend in fact, there’s a pot full of gold at the end of the rainbow (unfortunately for us,  impossible to reach).

Another “game” of lights and shadows is the eclipse; it occurs when a celestial body is totally or partially obscured by another one. There are two types of eclipses: the lunar eclipse and the solar eclipse. In order for an eclipse to occur,  Sun, Earth and Moon must line up. The lunar eclipse occurs when the Earth is between the Moon and the Sun. When they’re aligned (moon isn’t a shining light, but it reflects the light of sun) there’s always a full moon but we can’t see it because it’s totally or partially obscured by the shadow of the Earth. Instead, the solar eclipse occurs when the Moon is between the Sun and the Earth and the Moon obscures the disk of the Sun; they’re very rare because they can be seen only in limited areas on Earth (the ones hit by the Moon shadow cone).

Unfortunately, we will have to wait for 2026 to see a total solar eclipse in Europe, while the next total lunar eclipse will be on 15th June.

Finally, I’d like to talk about auroras, or northern lights, natural lights that can be seen in the sky and which are characterised by red, green or blue “light arches” . They’re caused by the interaction of charged particles with the ionosphere (a band where molecules or atoms became ions adding or removing charged particle like electrons). These particles are diverted by the Earth magnetic field (a sort of atmosphere that surrounds the Earth) and attracted by the poles; here they enter the ionosphere where gases are ionized and emit light. Irrespective of “scientific” explanation, that could be boring according to someone, I think (I’ve only seen videos and images) that this is one of the most magical and exciting performances of Nature. October, February and March are the best months to see the polar aurora between 6 p.m. and 1 a.m. The Cree (a group of native Americans) called these phenomena the “Dance of the Spirits” because when these lights appeared, they thought that a link had been created between the afterlife and the Earth and that the spirits of the past were trying to contact us.

Why don’t we organize a journey to northern Norway? I’m really curious to see this phenomenon…mmm, arches of lights that dance in the sky. I think it’s fantastic, isn’t it?

Happy birthday!

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