From moonlight to the microwave: your science questions answered

Q How does the moon shine what triggers the reflection and how? asks Manish Kunwar

A As Professor Manuel Grande from Aberystwyth University explains, the moon isn’t basically a silvery mirror. “It is very challenging to get a surface which is both entirely white or entirely black,” he says. “Really the moon is fairly black. In noticeable light it reflects about twelve%. But there is an awful great deal of sunlight falling on it, so it seems to be quite brilliant.”

And the reflections can lead to troubles. “When we built our X-ray spectrometer for Sensible-one, the very first European moon mission, we actually had a whole lot of difficulty trying to keep this reflected sunlight out of the instrument.” In truth, he says: “In reduced moon orbit, the amount of light is not so diverse to what you see from a plane on Earth if you’re flying over a desert.”

But what is the moon really created of? “Most of the surface is created of either anorthosite (a variety of feldspar) – the light, silver-coloured materials you see towards the edges of the disk – or else basalt [which kinds] the dark regions: seas or maria. The ilmenite (titanium-wealthy) locations are notably black,” he says.

Q Why did the salt articles of the oceans continue to be almost consistent above hundreds of thousands of many years in spite of the reality that rivers carry enormous quantities of salt into the sea? asks Thoralf Schubert

A Levels of rainfall, evaporation and melting sea ice all have an effect on the salinity of seawater by incorporating or getting rid of water, but the complete amount of salt in the ocean remains pretty significantly continuous. When rain (which is somewhat acidic) falls, it washes over land, weathering and eroding rocks and carrying off salts, chiefly calcium carbonate and silicates, into streams which wend their way to the seas. Chloride ions are not a significant part of river water it is imagined that they ended up in the oceans as a end result of volcanic processes which occurred in the early background of the planet.

At 1st glance, it looks like a one particular-way street. Nonetheless, the salt content material of the oceans is not continuously rising. Instead, a “steady-state issue” exists, meaning that the input of salts into the oceans rather much balances the output.

These depend on the sort of salt. Calcium and carbonate ions, for illustration, are employed by marine creatures such as crustaceans to make their shells. Soon after they die, the shells type sediments on the ocean floor and sooner or later outcome in the formation of limestone.

Salts can also be locked up in clays at the bottom of the ocean, while regions around hydrothermal vents on the ocean floor can both spew salts into the water and remove them.

Though calcium and carbonate ions are portion of a fairly quick cycle, sodium and chloride ions hang about in the oceans for hundreds of thousands of years, but can kind sound deposits (normally in enclosed seas) if sufficient water is evaporated.

In addition, when seawater crashes in excess of coasts (which has happened a great deal this yr), some of it settles on the land, leaving salt residues.

Q Does taking a scorching bath impact male fertility? asks Chris Davies

A Taking a prolonged soak in a sizzling bath might seem heavenly, but as Dr Allan Pacey from the University of Sheffield factors out, the body is meticulously created to hold specific locations cool. “The sperm manufacturing approach needs testicles to be a couple of degrees cooler than body temperature. This is why they hang outside the physique,” he says. “So theoretically, anything that increases the temperature of the testicles for any length of time may hinder sperm production and therefore decrease male fertility.”

But it is not only the hot tub that has been suspected of causing troubles: “Previous reviews have advised that investing also prolonged in a bath or saunas or utilizing a doing work laptop on your lap might increase testicular temperature sufficiently to do this. Nevertheless, undertaking definitive research is tough since guys frequently undertake a selection of actions that might affect their testicles.”

One such factor is a chap’s choice of trousers. “In a recent multicentre review, researchers at the universities of Sheffield and Manchester found that sporting loose pants was linked with greater sperm good quality,” says Pacey. “Consequently, it may possibly be concluded that wearing restrictive underwear or paying as well lengthy in a sizzling bath might harm sperm manufacturing. But that precise research has never ever been accomplished.”

Q How does a microwave oven operate? And is it secure to stand close to it? asks mathsdude

A A microwave oven utilizes electromagnetic radiation (essentially high frequency radio waves) to heat up food. These microwaves are produced by a nifty gadget known as a magnetron, which includes a metal filament that heats up and emits electrons. The electrons are spun about by a magnet and in the procedure result in the radiation of microwaves, which are then directed towards the cooking chamber. When the oven is turned on, the foods within heats up.

But, you will notice, only the food gets sizzling – the dish it sits on stays cold. This is due to the fact the microwaves energise only water molecules and your foods is packed with water. Why water? Properly, a water molecule is polar it has a positively charged region and a negatively charged region, meaning that it can interact with an electric discipline.

To comprehend how this works, 1st think of a man or woman holding the finish of a rope that is attached to a wall and waggling it up and down. You’d see that the rope flips among peaks and troughs at distinct spots even though other points in the rope will not seem to move at all. This is referred to as a “standing wave”.

Within the microwave oven, the metal walls reflect the electromagnetic radiation and, like the rope-wagglers, develop standing waves. Inside of the cooking chamber, the peaks and troughs of the electrical and magnetic fields are flipping more than two billion occasions a 2nd. The polar water molecules interact with the electrical discipline and, as it flips, they rotate to adjust their orientation. This generates friction and consequently heat and it is this heat that cooks the meals.

A turntable is essential to make sure that the meals is heated evenly, otherwise the standing waves would result in hot spots at the peaks and troughs of the electrical area and cold spots at the factors midway among. One bonus of employing a microwave oven is that microwaves penetrate into the food, which means your meal is rapidly heated correct the way by means of. Contrast this to heating your dinner up on the hob there, heat is transferred via a laborious game of pass-the-parcel from the outdoors to the centre.

And there is no want to dread a microwave oven. The door is manufactured of glass with a mesh that reflects the microwaves back into the chamber and prevents the radiation escaping.

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