My Science School

What you need:

A thick rubber band

What to do:

1. Hold the rubber band between your two index fingers without stretching it. Place it against your forehead or your cheek. Note if the rubber band feels warm or cool to the touch.

2. Now, move the band away from your face. Then stretch it out and quickly hold it back against your forehead (still stretched out). Does the rubber band feel warm or cool now?

3. Move the band away from your face again, still holding it stretched. Once it is away, let it spring back to its original shape and quickly place it against your forehead  How does it feel now?

4. Repeat this several times until you are certain about the results.

What happens:

When the band is stretched out it feels warm against your forehead. When it is relaxed, it feels cool.

Also, the thicker the rubber band, the more temperature change you will feel

Why?

First, the rubber band is held against your forehead or your cheek because they are the more sensitive areas on your body. There is a universal law that states that energy can neither be created nor destroyed; it is simply transferred from one form to another.

When you stretch the rubber band, you put some energy into the motion. This energy is absorbed by the band, its internal energy increases and takes the form of heat. When you touch the band to your head, some of this increased energy flows from the band to your forehead (heat is a form of energy that always flows from hot to cold). That is why you find it warm.

When you release the band, the extra energy is also released. So the rubber band cools down. When you hold it against your forehead, the heat from your skin flows into the band. And it feels cool.

Picture Credit : Google

What you need:

• 12 identical iron nails
• A block of wood
• A hammer
• Adult supervision

What to do:

1. Hammer one nail into the wooden block. It should stand upright on the block.

2. Can you balance the other nails over it?

3. Lay one nail flat on a table or on any even surface.

4. Place the other nails along the horizontal nail's length with their heads side-by-side as shown in the picture.

5. Lay the last nail over the heads of the others in such a way that its tail faces the head of the first horizontal nail.

6. Carefully, lift up this entire weaving of nails and place it on the head of the upright nail standing on the block of wood.

What happens:

If you try to balance the other nails on the upright nail without the weaving, they all fall over.

But the interwoven nails hold up on the single nail pretty well!

Why?

The 'Centre of gravity' is the point inside a body, where all its weight is concentrated. For an evenly-shaped form, like a ball, the centre of gravity lies at its centre. But for odd shapes, like a nail, the centre of gravity is shifted towards the heavier end. For the human body, the centre of gravity changes depending on the position the body is in!

In this case, the interwoven structure of nails becomes stable when its centre of gravity lies at the point resting on the bottom nail. If you have put too many nails to the left or to the right, the centre of gravity shifts to the heavier side causing the structure to topple.

Picture Credit : Google

A European Mars orbiter has found water ice in the heart of the Valles Marineris canyon system- an area about the size of the Netherlands

• Water ice may be lying just centimetres below the Martian surface at one of the planet's most well known sites the Valles Marineris, a huge 3.000-km-long canyon system located along the equator of Mars.
• Ten times longer and five times deeper than the Grand Canyon on Earth, the Valles Marineris is named after NASA's Mariner 9 Mars orbiter, which discovered it in 1971.
• Now, 50 years later, the ESA's ExoMars Trace Gas Orbiter has identified vast amounts of hydrogen in the soil's upper surface layers at the centre of the canyon.
• Alexey Malakhov, a senior scientist at the Space Research Institute of the Russian Academy of Sciences and one of the nine authors of a new paper on the subject, says "We found a central part of Valles Marineris to be packed full of water-far more water than we expected. This is very much like Earth's permafrost regions, where water ice permanently persists under dry soil because of the constant low temperatures"
• Researchers added that if all of the hydrogen they have detected is present in the form of water ice, the compound could make up as much as 40% of near-surface material in the area.

Picture Credit : Google

The sun is mostly composed of hydrogen and helium, which are the most abundant elements in the universe and were formed shortly after the Big Bang. The sun also contains a small fraction of heavier elements such as carbon, oxygen and iron. These elements did not exist early in the history of the universe. They were formed inside stars, where temperature and pressure are so high that atoms merge to form bigger ones through powerful fusion reactions. Throughout their life or when they explode at the end of their life, stars disseminate these elements in space. The space between stars is thus far from empty and contains atoms, molecules and ions, although at very low densities. When they assembled, both the sun and the earth included some of these elements formed in previous stars. In fact, we are all made of this stardust!

There are two main forces at work in nuclear fusion: the electromagnetic force and the strong nuclear force. The repulsive electromagnetic force between positively-charge nuclei is long-range but relatively weak, while the attractive strong nuclear force is short-range but strong. When two nuclei are far enough apart, the repulsive electromagnetic force dominates, holding the nuclei apart. As the two nuclei get closer, the electromagnetic repulsion gets stronger and it gets harder and harder to push the nuclei together. When the two nuclei get close enough, the attractive short-range nuclear force dominates and the two nuclei stick together to form a new nucleus. For this reason, it takes a lot of pressure to push nuclei close enough that they fuse together.

In principle, any two nuclei can be fused into a single nucleus. However, it is the easiest to fuse (and the most energy is released from) nuclei that have little electromagnetic repulsion because they have little electric charge. The nuclei with the least electric charge are the lighter elements, such as hydrogen and helium. In stars, most of the fusion taking place is hydrogen fusing with itself or with other light elements. Since gravity is what provides the pressure to ignite nuclear fusion in stars, and since gravity is caused by mass, all you need is a big enough mass of hydrogen in order to end up with burning stars. There is very little oxygen in stars. The oxygen that is there was created by hydrogen fusing repeatedly until it made the oxygen.

Picture Credit : Google

The beauty of Planet Earth lies in its diversity. The plants, birds and animals in one part of the world are different from those in the other part. While polar bears roam the Arctic region, penguins colonise the Antarctic region. While neem trees are native to the Indian subcontinent, baobab trees are native to parts of Africa. Imagine how dull it would be if all the species are distributed everywhere on the planet! Unfortunately, this could happen sooner, thanks to human activities.

The first-ever global analysis of plant diversity has shown that the world's flora is growing increasingly uniform, even on isolated islands. Due to the introduction of invasive species, scientists war, the world is headed for a new geological epoch, called the 'Homogecene. Humans have collapsed the distance between different ecoregions worldwide, and scientists are concerned this could one day create a New Pangaea'. (About 300 million years ago, Earth didn't have seven continents, but instead remained as one massive supercontinent called Pangaea.)

Many scientists argue that we are entering a period characterised by widespread faunal and floral homogenisation, dubbed the 'Homogecene'.

Homogenisation is the replacement of local biotas by non-indigenous and expanding species that can co-exist with humans. It reduces diversity at regional and global scales. With the introduction of invasive species, biological borders fade and distinct habitats grow increasingly similar.

Humans' role

What are invasive species? Invasive species are organisms that are introduced to a new geographical location, where they pose a threat to the environment. They could be insects, plants, animals or pathogens. These species start to grow and multiply quickly in the absence of natural predators from their original homes.

How do invasive species spread? Some species arrive in a new area through migration. Some are spread unintentionally by human activities. When people travel, they often inadvertently carry alien species along. For instance, insects may arrive in a new place by travelling on luggages. Some species are introduced on purpose as pets or to combat pests, and they turn out to be invasive in the new place.

Findings of the study

The first-ever global analysis of plant diversity, published in Nature Communications, drew on floral data from 658 regions around the world, including 189,762 flowering plant species.

The authors suggest alien plants are more likely to become naturalised in a distant environment when the climate, and especially the temperature, is similar to their previous home.

Picture Credit : Google

Elusive cosmic objects with masses comparable to those of planets in our solar system, rogue planets do not orbit a star, but instead roam freely on their own. While not many of these rogue planets were known until recently, a group of astronomers have just discovered at least 70 new rogue planets in our galaxy- the largest group of rogue planets ever discovered.

As rogue planets are far away from any star that can illuminate them, it is nearly impossible to image them. The team of researchers involved in this discovery, which was published in December 2021 in Nature Astronomy, utilised the fact that these planets are hot enough to glow in the few million years after their formation. Using sensitive cameras on super large telescopes, these can thus be detected.

Decades of data

Using two decades of data from a number of telescopes, both ground based and those in space, the team were able to measure the tiny motions, the colours and luminosities of millions of sources in a large area. These measurements then allowed them to identify the faintest objects in the region, thus spotting the rogue planets.

The study, which marks a grand success for the collaboration of ground-based and space-based telescopes, also suggests that there could be more of these nomadic planets that have proved to be elusive so far.

Mystery remains

By studying these starless planets, scientists might be able to figure out how these mysterious rogue planets form. While some believe these planets could have been kicked out from their parent system, and others think they are formed from the collapse of a gas cloud that doesn't lead to the formation of a star, the actual mechanism by which they are formed remains unknown.

Even though our current technology has enabled scientists to find at least 70 new rogue planets with mass comparable to Jupiter, it is found wanting to study them further. Greater advances in technology would certainly be key to unlock the entire mystery of rogue planets.

Picture Credit : Google

At the core of the sun, gravitational attraction produces immense pressure and temperature, which can reach more than 27 million degrees Fahrenheit (15 million degrees Celsius). Hydrogen atoms get compressed and fuse together, creating helium. This process is called nuclear fusion.

Nuclear fusion produces huge amounts of energy. The energy radiates outward to the sun's surface, atmosphere and beyond. From the core, energy moves to the radiative zone, where it bounces around for up to 1 million years before moving up to the convective zone, the upper layer of the sun's interior. The temperature here drops below 3.5 million degrees F (2 million degrees C). Large bubbles of hot plasma form a soup of ionized atoms and move upward to the photosphere.

The temperature in the photosphere is about 10,000 degrees F (5,500 degrees C). It is here that the sun's radiation is detected as visible light. Sunspots on the photosphere are cooler and darker than the surrounding area. At the center of big sunspots the temperature can be as low as 7,300 degrees F (4,000 degrees C).

The chromosphere, the next layer of the sun's atmosphere is a bit cooler — about 7,800 degrees F (4,320 degrees C). According to the National Solar Observatory (NSO), chromosphere literally means "sphere of color." Visible light from the chromosphere is usually too weak to be seen against the brighter photosphere, but during total solar eclipses, when the moon covers the photosphere, the chromosphere can be seen as a red rim around the sun.

Credit : Space.com

Picture Credit : Google

For the first time in history, a spacecraft has touched the Sun. NASA’s Parker Solar Probe has now flown through the Sun’s upper atmosphere – the corona – and sampled particles and magnetic fields there.

The new milestone marks one major step for Parker Solar Probe and one giant leap for solar science. Just as landing on the Moon allowed scientists to understand how it was formed, touching the very stuff the Sun is made of will help scientists uncover critical information about our closest star and its influence on the solar system.

On April 28, 2021, during its eighth flyby of the Sun, Parker Solar Probe encountered the specific magnetic and particle conditions at 18.8 solar radii (8.127 million miles) above the solar surface that told scientists it had crossed the Alfvén critical surface for the first time and finally entered the solar atmosphere.

As it circles closer to the solar surface, Parker is making new discoveries that other spacecraft were too far away to see, including from within the solar wind – the flow of particles from the Sun that can influence us at Earth. In 2019, Parker discovered that magnetic zig-zag structures in the solar wind, called switchbacks, are plentiful close to the Sun. But how and where they form remained a mystery.

Credit : Sci-Tech Daily 

Picture Credit : Google

The Sun doesn’t have a solid surface like Earth and the other rocky planets and moons. The part of the Sun commonly called its surface is the photosphere. The word photosphere means "light sphere" – which is apt because this is the layer that emits the most visible light. It’s what we see from Earth with our eyes. (Hopefully, it goes without saying – but never look directly at the Sun without protecting your eyes.)

Although we call it the surface, the photosphere is actually the first layer of the solar atmosphere. It's about 250 miles thick, with temperatures reaching about 10,000 degrees Fahrenheit (5,500 degrees Celsius). That's much cooler than the blazing core, but it's still hot enough to make carbon – like diamonds and graphite – not just melt, but boil. Most of the Sun's radiation escapes outward from the photosphere into space.

The Sun doesn’t have a solid surface like Earth and the other rocky planets and moons. The part of the Sun commonly called its surface is the photosphere. The word photosphere means "light sphere" – which is apt because this is the layer that emits the most visible light. It’s what we see from Earth with our eyes. (Hopefully, it goes without saying – but never look directly at the Sun without protecting your eyes.)

Although we call it the surface, the photosphere is actually the first layer of the solar atmosphere. It's about 250 miles thick, with temperatures reaching about 10,000 degrees Fahrenheit (5,500 degrees Celsius). That's much cooler than the blazing core, but it's still hot enough to make carbon – like diamonds and graphite – not just melt, but boil. Most of the Sun's radiation escapes outward from the photosphere into space.

Picture Credit : Google

Compared to Earth, the Sun is enormous! It contains 99.86% of all of the mass of the entire Solar System. The Sun is 864,400 miles (1,391,000 kilometers) across. This is about 109 times the diameter of Earth. The Sun weighs about 333,000 times as much as Earth. It is so large that about 1,300,000 planet Earths can fit inside of it. Earth is about the size of an average sunspot!

It's possible that the sun is even larger than previously thought. Xavier Jubier, an engineer and solar eclipse researcher, creates detailed models of solar and lunar eclipses to determine precisely where the moon's shadow would fall during the solar eclipse. But when he matched actual photos and historical observations with the models, he found precise eclipse shapes only made sense if he scaled up the sun's radius by a few hundred kilometers.

Even missions like NASA's Solar Dynamics Observatory (SDO) and measurements of the inner planets across the face of the sun don't refine the star's radius as precisely as desired.

Credit : Space.com

Picture Credit : Google

In 1923, W.H. Bragg left for the Royal Institution in London and Kathleen went with him. It was around this time that X-ray crystallography began to be used to look inside organic molecules — carbon atoms with other elemental atoms attached. The process involved a lot of calculations, and Kathleen saw the need for crystallography look-up tables that would greatly speed things up. Together with her lab-mate, they created the Astbury-Yardley tables, which formed the basis for what became the International Tables for X-ray Crystallography.

While at the Royal Institution, Kathleen met Thomas Lonsdale, an engineering student who would become her husband. They married in 1927 and then moved to Leeds to accommodate his new job. Meanwhile, Kathleen joined the University of Leeds’ physics department and worked on X-ray diffraction.

It was at the University of Leeds that Kathleen made a name for herself. Chemists had been arguing about the atomic structure of benzene for decades. In 1865, chemist August Keuklé had a dream that included a vision of the structure of benzene. He saw atoms dancing around and transforming into an ouroboros — a serpent swallowing its own tail. Kathleen was given hexamethylbenzene crystals to study, and in 1929 she was able to prove conclusively that the benzene molecule is in fact a flat ring. This was a remarkable achievement, especially considering that all the calculations had to be done by hand. And as if that wasn’t enough of a contribution, Kathleen was also the first to apply Fourier methods to X-ray pattern analysis as she solved the structure for another type of benzene — hexachlorobenzene.

Kathleen’s first child, Jane, arrived later that same year. The family soon moved back to London and had two more children in 1931 and 1934 — Nancy and Stephen. Although moving and raising children greatly disrupted Kathleen’s work, she kept her head in the crystallography game, doing calculations of structure factors by hand whenever she had the time. Soon, Sir Bragg shared good news: he’d been given an allowance so that Kathleen could hire a nanny and come back to work at the Royal Institution.

When Kathleen returned, there were no X-ray instruments available to her. She was able to secure a large electromagnet instead, so she pursued another interest — determining the magnetic properties of benzene-like compounds known as aromatics. By doing this, she was able to establish proof of molecular orbitals, but another chemist, Linus Pauling, beat her to publication.

Credit : Hack a Day

Picture Credit : Google

Kathleen Lonsdale was an Irish crystallographer and a pioneer in the use of X-rays to study crystals. Using X-ray diffraction, she proved that the benzene ring is flat.

Kathleen Lonsdale was born in 1903 in Newbridge, County Kildare, Ireland. She studied at Woodford County High School for Girls. She excelled in mathematics and science. However, she had to attend classes in physics, chemistry and mathematics at the boys' high school because the girls school didn't offer these subjects. She earned her Bachelor of Science degree from Bedford College for Women in 1922, graduating in physics with an M.Sc. from University College London in 1924. In 1924, she joined the crystallography research team headed by William Henry Bragg at the Royal Institution. Bragg was a pioneer of X-ray diffraction. After her marriage, she moved to the University of Leeds Department of Physics, where she continued to work on X-ray diffraction and studied the structure of benzene. In 1929, her results showed that the benzene ring was flat, something that chemists had been arguing about for 60 years. She developed an X-ray technique to obtain the accurate measurement (to seven figures) of the distance between carbon atoms in diamond. She also applied crystallographic techniques to medical problems.

She became professor of chemistry at University College, London, in 1949. In 1956, she was made Dame of the British Empire

During her career she attained several firsts for female scientists, including being one of the first two women elected a Fellow of the Royal Society (FRS) in 1945 (along with bacterial chemist Marjory Stephenson), first woman tenured professor at University College London, first woman president of the International Union of Crystallography, and first woman president of the British Association for the Advancement of Science.

Picture Credit : Google

What you need:

Several identical black plastic bags-you can use the packet of garbage bags available at a local store

Scissors

Duct tape (black or clear is preferable)

A pump

A string

A hot, sunny day

What to do:

1. To make the balloon, cut off the tops (handles) of each of the bags. Now cut off the bottoms of all the bags except two. (You can use five to seven bags)

2. Now, on a flat surface, arrange the bags in the shape of a tube. The mouth of one bag should overlap at least an inch with the bottom of another. The two ends of the tube should be the bags whose bases are intact.

3. Tape all the bags together in the shape of the tube (make sure the tape overlaps both bags enough or they will fall apart). Check the bags for any tears and tape them up too.

4. Once the long balloon bag is ready, cut a small hole into one end of the bag to inflate it with the pump. Seal it with duct tape once the bag is completely filled with air.

5. Tie a long string around one end of the balloon.

6. Take the balloon outdoors on a hot, sunny day. Hold the string or tether it to the ground and wait

What happens:

 It takes some time (anywhere between 10 and 30 minutes) but the bag slowly rises and floats like a balloon. If not tethered, it will float away in the wind!

Why?

The bag is black in colour for a reason. Black absorbs heat really well. The outside of the bag gets heated in the sun and this heats up the air inside the bag too. As the air heats, it expands and its molecules spread out. This space between the molecules makes the hot air less dense (and hence lighter) than the surrounding cooler air. So the balloon rises up and floats above the cooler air.

Picture Credit : Google

What you need:

Several lightweight plastic bags (identical)

Scissors

Clear tape

What to do:

1. Cut off the tops (handles) of each of the bags. Now cut off the bottoms of all the bags except one. (You can use five to seven bags but they need to be really lightweight)

2. Now, on a flat surface, arrange the bags in the shape of a tube. The mouth of one bag should align with the bottom of another. The end of the tube should be the bag whose bottom is intact.

3. Tape all the bags together in the shape of the tube. Check the bags for any tears and tape them up too.

4. Once the long bag is ready, try inflating it by breathing into it. How many breaths do you need?

5. Let all of the air out from the bag again.

6. Ask someone to hold the closed end of the bag straight and horizontal for you.

7. Now, hold the mouth of the long bag open and away from your mouth (at least 25 cm away) and blow a big breath of air into it. Quickly seal the mouth with your hand.

What happens:

When you try to inflate the bag, you put your mouth against the opening of the bag and blow into it. This technique needs a lot of breath before the bag inflates fully.

When you hold the bag away from your mouth and blow into it, it inflates faster and may even inflate fully in a single breath!

Why?

Daniel Bernoulli, an 18th-Century Swiss mathematician and physicist, is remembered for giving us something known as Bernoulli's principle that applies to moving fluids (since air flows, it is also considered a fluid). According to this principle, the faster the air flows over a surface, the less it pushes on the surface i.e. the pressure exerted by the air decreases when its speed increases.

When you blow a big breath of air slightly away from the mouth of the bag, you increase the speed of the air molecules flowing into the bag. This creates an area of low pressure inside the bag's mouth. But the surrounding air still has higher pressure so it pushes into the bag to equalize the low pressure your breath created. Thus, the bag inflates faster because the surrounding air is pushed into the bag along with your breath.

On the other hand, when you breathe directly into the mouth of the bag, only the air from your lungs goes into the bag. That is why it takes longer to inflate.

Picture Credit : Google

What you need:

A straw

A friend

What to do:

1. Bend each end of the straw at a right angle to the centre so that the straw has an S-shape.

2. Pinch the bent ends of the straw shut and start twisting the straw in a pedalling motion.

3. Twist the straw until its whole length is compressed, until no more can be twisted.

4. Now ask your friend to flick the centre of this twisted straw hard, with her/his finger.

What happens:

The straw pops like a tiny cracker!

Why?

When you pinch the ends of the straw shut, you trap some air inside the straw. Winding the straw causes this air to be pushed into an increasingly small space.

There comes a point when you can't wind the straw further. At this point, all the air is compressed into a small pocket at the centre of the straw. Here, the air pressure inside the straw is much higher than the air pressure outside because the trapped air is pushing really hard against the inner walls. When your friend hits this portion of the straw, it ruptures and you hear a 'pop' as all the trapped air rushes out.

Picture Credit : Google