Category Science

Why have beach sands different colors?

Sand is basically the small particles of eroded larger rocks. The erosion is caused by several factors, including water and wind. Depending on the geography, the composition and colours of the sand vary. For instance, beach sand could be lighter because of calcium carbonate desposits from shells and skeletons of marine creatures. Meanwhile, desert sand comprises fine, light-weight particles that have been brought in by wind. River sand is likely to be coarse, containing even bright-coloured stones.

On some beaches, sand grain size composition varies with distance from the water. A greater proportion of finer, smaller sand grains may be pushed higher up the beach by waves or by wind, whereas larger, coarser grains are deposited closer to the water. However, beaches are complex and highly variable environments, and there are many areas where this distribution is not found because there are many conditions that affect sand size and distribution. Additional factors influencing sand grain size include the nearshore and offshore seafloor features, substrate type, sand source, currents, wind exposure, and coastline shape.

Beach sand can appear fairly uniform, but it is actually a complex mixture of substances with various dimensions. When scientists study sand, some qualities are particularly useful in characterizing the type of sand. These qualities include the colors, texture, and size of the sand grains and their material origins. In general, sand observations can be divided into three broad categories:

observations about size,

observations about shape, and

observations about the probable source of the sand.

 From these three characteristics scientists can learn about the physical, chemical, and biological processes at the beach from which the sand came.

The Wentworth scale is one system used to classify sediments, including sand, by grain size. The word sediment is a general term for mineral particles, for example individual sand grains, which have been created by the weathering of rocks and soil and transported by natural processes, like water and wind. In decreasing order of size, sediments include boulders, gravel, sand, and silt.

Credit : Manoa Hawaii

Picture Credit : Google 

How many watts is a lightning strike?

Lightning is a natural electrical discharge created by imbalances between a cumulonimbus cloud and the ground or within itself. Lightning is pure electricity involving small particles with positive and negative charges that pull toward each other like the north and south ends of magnets. Lightnings are scary and of course dangerous, but it is a subject of fascination for scientists. During thunderstorms, scientists  witness a lot of lightning.  On an average, scientists have mapped, there are about 100 lightnings per second worldwide.That’s a whopping number. Imagine the amount of energy that’s shooting up from the clouds. Each bolt can contain up to one billion volts of electricity. This means a single lightning flash has enough energy to light a 100-watt bulb for three months!  So, How many homes could a lightning bolt power? Every lightning bolt on Earth in one year, captured perfectly with no loss of energy, would contain about 4*10^17 joules of energy. Thus, all the lightning in the entire world could only power 8% of US households. Human body can tolerate a maximum of between 20,000 and 50,000 volts, which might prove to be lethal. In most cases, a person’s heart will stop after being struck by lightning, so the key to survival is having someone nearby who can administer CPR. Even if you survive, a lightning strike will have long-lasting effects on your body, including memory issues, muscle soreness and changes in mood.

People often confuse lightning with thunder. To put it simply, lightning is electricity; thunder is sound. In other words, lightning is the sudden flash of light spotted in the sky, while thunder is the roaring, cracking sound that is commonly heard during thunderstorms. And because light travels faster than sound, lightning is seen before thunder can be heard.

Picture Credit : Google 

How heavy can clouds be?

Clouds are like light fluffy, white cotton candies on the sky. How much could they weigh? Our first guess would be “Since they float in the air, perhaps, close to nothing!” Well, we are wrong. Researchers have calculated that the average cumulus cloud weighs an incredible 5,00,000 kg. That’s a hundred elephants!

Clouds, after all, are made up of water, and water is quite heavy. The density of cumulus clouds is around 0.5 gram of water per cubic metre. A 1 cubic km cloud contains 1 billion cubic metre. Doing the math: 1,000,000,000 x 0.5 = 500,000,000 grams of water droplets in our cloud. That is about 5,00,000 kg or 1.1 million pounds (about 551 tonnes).

So now, the next question is, how does all this massive weight stay afloat in the sky? How come they don’t fall on our heads? Because the air below it is even heavier. That is, the density of the same volume of cloud material is less than the density of the same amount of dry air. Just as oil floats on water because it is less dense, clouds float on air because the moist air in clouds is less dense than dry air.

Picture Credit : Google 

What does app limit do on iPhone?

At the Worldwide Developer’s Conference (WWDC) 2018, Apple announced a new feature for iOS 12- the ability to limit how long you use individual apps via the App Limit setting. Say you don’t want to spend more than an hour on Instagram per day; set a limit and you’ll receive a full-screen notification when your time is up. It also syncs across your other iOS devices, so that you can’t avoid the limit. Not only can you see the time you’ve spent on individual apps, but you can set time limits as well.

Say you don’t want to spend more than an hour on Instagram per day. Set a limit and Apple will send a full-screen notification when time is up. Better yet, it syncs across your other iOS devices, so you can’t cheat that way. Unfortunately, it doesn’t seem you can set a hard limit. As far as we can tell, it’s pretty easy to extend your time after you receive the notification to stop there’s an ‘ignore limit’ prompt right on the alert. Still, it’s meant to be more of a deterrent than a permanent measure. Parents will also be happy to know they can apply similar allowances to their kids’ devices. Parents can limit how much time their kids spend in some apps, while allowing others – like educational apps – to be used unfettered.

It’s a small but important update. The average person will spend nearly two hours on social media apps (including YouTube) every day, and that number is expected to increase. Tools like these could help us buck that unfortunate trend.

Credit : The next web 

Picture Credit : Google 

What did Peter Henlein invent?

Peter Henlein, a locksmith from Nuremburg, Germany, is considered as the inventor of the modern day watch. He was one of the first craftsmen to make small ornamental Taschenuhren, portable clocks worn as pendants or attached to clothing, which were regarded as the first watches. The Pomander Watch is one of the world’s earliest known portable timepieces and is thought to have been made by Henlein in 1505.

Peter Henlein was born in 1485, and very little is known about his early life. It is most probable that he became apprentice as a repair man and locksmith. His appearance in history books start on September 7, 1504 after he was involved in a brawl in which his friend and fellow locksmith George Glaser was killed. Peter immediately went to the local Franciscan monastery where he found safety. Four years later he returned to the Nuremberg where he became one of the most famous locksmiths, who was especially praised for his ability to create small spring-powered brass clock which were then very rare and expensive. With such popularity, it was not strange that local and distant nobility contacted him on regular basis, demanding ever more beautiful and smaller clock designs. As far historical records are concerned, Peter’s first clock was made in 1510, and by 1541 he was well known for his craft and has been tasked on building not only small clocks but also big tower clock for Lichtenau castle.

Even though his spring designs were not particular accurate (they could lose several hours during one day’s work) or even portable (with around 3 inches in size, they were more suited to be worn as a pendant than in pocket), clocks that were made by Peter Henlein soon became sensation in Europe scientific circles and later on by general European population.

Today, Peter Henlein is regarded as a father of modern clocks even though he was not the first locksmith that made small clock designs or was responsible for the discovery of key clock component –mainspring. He died in 1547 knowing that his invention will live forever.

Credit : History of watch

Picture Credit :Google 

WHY IS THE STRATOSPHERE VITAL?

The stratosphere has a layer of ozone gas, which acts like a thick umbrella covering the layers beneath. By absorbing most of the harmful UV radiation from the Sun, the ozone layer prevents it from reaching the surface of the Earth, thus enabling the survival of life on the planet.

Stratosphere could be aptly called the ‘protection blanket’ of Earth. It extends up to 600 kms from the surface of the earth and it is the second layer of the Earth’s atmosphere, right above troposphere.

Stratosphere houses in it the most important layer called Ozone (O3), which acts as an absorber of the harmful UV radiations of the Sun (of about 90%) and thereby protecting us from diseases like Cancer, skin burn etc.

Its non-turbulance and stable, non-convection character makes it possible for the jets to cruise easily, hence they are flown here.

When Volcanic eruptions occur, the ejected material reaches as high as Stratosphere and it stays there for long period, as it doesn’t allow the circulation, there by leading to stratifying the volcanic particles and cooling down of the Earth surface.

However, such an important layer is being perforated by us through the extensive use of the chloro-fluro-carbons which happen to destroy the ozone molecules.

There is also an idea which the scientists are considering that could result in the slowing down of the Earth’s heating, i.e., by adding the man-made materials to stratosphere. Though the feasibility of this idea is yet to be verified. Thus, is the importance of the Stratosphere layer.

Credit: medium.com

Picture credit: Google