What is no-till farming?

It is a method of farming by which crops are grown without disturbing the soil by tilling. If there is no tilling the crop residue on the soil prevents evaporation of rain water and more water infiltrates the soil. There is better retention of organic matter in the soil and nutrients are well recycled, thereby improving the fertility of the soil. It minimises soil erosion and no ploughing means there is no air-blown dust. It is more profitable as it does away with the labour, irrigation and machinery associated with tilling.

Tilling also damages ancient structures like burial mounds under the earth as archaeologists have found in the UK

It was Edward Faulkner's book "Plowman's Folly" which started the idea of no-till farming in the 1940s. No-till farming is widely practised in the U.S. Indian farmers started adopting the practice in the 1960s. In the Indo-Gangetic plains, rice-wheat cultivation is done using this method. In parts of Andhra Pradesh, rice-maize cultivation is done without tilling.

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What is Reverse Osmosis?

Osmosis is the movement of a thinner liquid into a thicker liquid through a semipermeable partition or membrane when physical external pressure is applied. The thinner liquid dilutes the thicker solution.

Osmosis is a process that occurs in our bodies all the time. For example, after the food we eat is broken down in the stomach, it passes through the intestines. The intestines contract to force the nutrients, which are thinner, to pass through the walls of the intestines into the blood, which is a thicker solution.

In reverse osmosis, exactly the opposite happens. Water that has a high concentration of impurities is put under pressure and forced through a semipermeable partition leaving all the larger particles behind. This process renders the impure water as well as salty water (here the process is called desalination) potable enough to drink.

This is why RO is used in water purifiers. In a purifier, water passes through several stages-a sediment filter, activated carbon filter and ultraviolet light. RO is the final stage. The larger molecules cannot pass through these various filters and RO removes the harmful particles, metal ions and bacteria in the water that remains. This cleans the water thoroughly and prevents diseases caused by contaminated water.

Reverse osmosis is also used in the food industry to make concentrated juices. The traditional heat treatment reduces the quality of heat-sensitive fruits such as oranges. RO reduces the quantity of water in the juice, so it doesn't need to be thickened by heating. For instance, in the production of maple syrup, RO is used to remove the water from the sap before it is boiled into a syrup. Dairy industries use RO to make concentrated milk and whey protein powders.

Since RO units are also manufactured in compact sizes, they can be installed easily which is why a number of home water filters come equipped with it.

RO removes almost all the minerals in the water, which leaves it tasteless. Some RO systems come with a remineralisation filter that adds minerals to the water and makes it more flavourful!

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Creating three-dimensional objects with sound

Additive manufacturing, more commonly identified as 3D printing, allows for the fabrication of complex parts from functional or biological materials. As objects are constructed one line or one layer at a time, conventional 3D printing can be a slow process.

Scientists from the Max Planck Institute for Medical Research and the Heidelberg University have demonstrated a new technology to form a 3D object from smaller building blocks in a single step. They utilise the concept of multiple acoustic holograms to generate pressure fields.

Sound exerts force

If you've ever been near a powerful loudspeaker, you would be aware that sound waves exert forces on matter. When high-frequency ultrasound that is inaudible to the human car is used, the wavelengths can be pushed into the microscopic realm. This would allow researchers to manipulate building blocks that are incredibly small, including biological cells.

This research group had previously shown how to form ultrasound using acoustic holograms, which are 30 printed plates made to encode a specific sound field. The scientists had devised a fabrication concept to use these sound fields to assemble materials in 2D patterns.

Holds promise

For this research, the team expanded the concept further by capturing particles and cells freely floating in water and assembling them into 3D shapes. Additionally, the new method works with materials such as glass, hydrogel beads, and biological cells.

Ultrasound affords the advantage that it is gentle for using biological cells and that it can travel deep into tissue. Hence, it can be used to remotely manipulate cells without harm. Scientists believe that their technology of creating 3D objects with sounds holds promise as it can provide a platform for the formation of tissues and cell cultures.

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How do cell phones work?

Also do you know why mobile phones are called cellular phones? Read on to find out...

A cellular phone is similar to a radio. However cell phones allow you to speak and listen at the same time because two separate frequencies are used to transmit and receive signals.

Cellular phones are also similar to cordless phones, which use a pair of frequencies for communication between the base unit and the handset. In the case of cellular phones, the base unit is located a much greater distance away from the mobile phone and is also capable of handling communications with several mobile units at a time.

Within a city, the phone company divides the area into small units called cells. It is for this reason that mobile phones are called cellular phones. In each cell, a tower is installed which has a radio transmitter and receiver, which is capable of communicating with several phones at a time. Each of these cells has a radius of about a couple of kilometres.

When one starts a telephone conversation, the mobile unit will communicate with the base unit in the cell that is nearest. This is similar to the operation of a cordless phone. If you are close to the base unit within a cell, the signal strength will be sufficient to carry on a conversation comfortably. However as one moves away from the base unit, the signal strength will reduce. The base unit senses this reduction in signal strength. Simultaneously, the adjoining cell detects that the signal strength from your phone is increasing and therefore you are moving closer to it. When the signal to the second cell becomes greater than that from the first cell, the conversation automatically switches to the second cell.

In addition every cell phone company will have one central office, which handles communication between the cell phones and ordinary landlines.

For good communication over an entire city, it is important to have a large number of cells, which overlap slightly. This will ensure that there is coverage at all points of the city and also that the communication is uniform. A larger number of cells allow the use of lower power transmitters, and results in less interference.

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Here's how to write emails

Emails have become a powerful tool since this is an era with need for instant communication. Emails can be used for both formal and informal communication. Here are a few tips on how to write them.

While writing an email, it is important to have an appropriate subject line, which states the topic and purpose. It conveys in just a couple of words or a phrase what the mail is about. Greeting - and closing- should be courteous. The content should contain short sentences and must be to the point. The font should be readable, and paragraphs should be small for easy reading. The email ends with the sender’s name. Formal mails additionally contain details such as designation, organisation address, contact number, etc.

Emails should be edited and proofread before being sent.

Sample of a formal email

Subject: Reservation of room at your hotel

Dear manager.

I am writing to make a reservation at your hotel for the next weekend. I require a double room for a family of three.

Kindly confirm my booking at the earliest

Yours faithfully


Sample of an informal email

Subject: Visiting Bengaluru


 I am really happy to tell you that I will be visiting Bengaluru next weekend. My parents and I are coming there to attend a close relatives wedding on Saturday. I will be visiting you on Sunday. We could meet our friends and have an outing together. I am sure we will have a great time.

Looking forward to meeting you.

Best wishes,


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A robot chef that learns from videos

You might not often think about it that way, but cooking is a difficult skill with a number of factors in play. Just ask a robot! While human beings can learn to cook through observation, the same cannot be done easily by a robot. Programming a robot that can make a variety of dishes is not only costly, but also time-consuming.

A group of researchers from the University of Cambridge have programmed their robotic chef with a cookbook - eight simple salad recipes. The robot was not only able to identify which recipe was being prepared after watching a video of a human demonstrating it, but was also then able to make it. The results were reported in the journal ‘IEEE Access.’

Simple salads

For this study, the researchers started off by devising eight simple salad recipes and then made videos of themselves making these. A publicly available neural network programmed to identify a range of different objects was then used to train the robot chef.

The robot watched 16 videos and was able to recognise the correct recipe 93% of the time (15 times out of 16), even though it detected only 83% of the actions of the human chef in the video. The robot was able to recognise that slight variations (portions or human error) were just that, and not a new recipe. It even recognised the demonstration of a new, ninth salad, added it to its cookbook and made it.

Hold it up for them

The researchers were amazed at the amount of nuance that the robot could grasp. For the robot to identify, the demonstrators had to hold up the fruit or vegetable so that the robot could see the whole fruit or vegetable, before it was chopped.

These videos, however, were nowhere like the food videos with fast cuts and visual effects that trend on social media. While these are too hard for a robot to follow at the moment, researchers believe that robot chefs will get better and faster at identifying ingredients in videos like those with time, thereby becoming capable of learning a range of recipes quickly.

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Scientist make accurate measurements with the help of various measuring tools. Let’s look at a few of them today.

pH Meter

A pH meter is an electric device that measures the concentration of hydrogen ions (or pH) in a solution to determine whether it is acidic or alkaline. It was invented in 1934 by the American chemist Arnold O. Beckman to measure the sourness of lemons.

It consists of a glass electrode that is sensitive to pH and another reference electrode. The device reads the potential difference between the two electrodes to arrive at results that are displayed electronically in the form of a pH value. This knowledge is critical in chemical lab work and healthcare.


A stethoscope is a diagnostic instrument commonly used by doctors to listen to sounds made inside the human body-in the lungs, heart and pulse points. The device has two ear buds that are connected by a flexible cord to a sensitive sound detector at the other end.

French physician Dr René Laennec first used a cylindrical roll of paper to listen to chest sounds instead of using his ear in the early 19th Century. Later he improved upon this to create the first stethoscope for medical use (‘Stethos' meaning 'chest’ in Greek).


A barometer is an instrument that measures the pressure exerted by the weight of the air in the atmosphere.

As changes in atmospheric pressure are directly related to changes in weather, a barometer is a useful instrument at all weather stations.

The device can be also used to measure altitude since atmospheric pressure changes with altitude.


It is an instrument used to estimate blood alcohol content (BAC) in one's breath. The instrument that is presently used by the police to discourage drinking and driving is a prototype developed by Robert Frank Borkenstein in 1954. The person exhales into a tube attached to the device which then reads the level of alcohol in the sample breath.

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What tool is used for accurate measurement?

Accurate measurements are made with the help of various measuring tools. Let's look at a few of them today

  • Glucometer

A glucometer or glucose meter is a medical device that is used to determine the concentration of glucose in the blood. The device is available in user-friendly forms like small hand-held devices or paper strips. People with diabetes often keep this device with them at home to regularly monitor their blood glucose/sugar levels.

  • Depth finder

Also called the echo sounder, this device is used on ships to determine the depth of water. The device uses reflected sound from the bottom of the water body to calculate the depth. It sends sound waves from the water surface and detects the reflected wave from the bottom (the echo). From the knowledge of the speed of sound in water and the time taken by the sound for the round trip, the distance travelled can be calculated and thus the depth.

The same device is used to detect underwater objects. Fishermen use it to detect the presence of big fish in the water.

  • Speedometer

A speedometer measures the speed of a moving vehicle and displays the speed for easy reference while the vehicle is in movement. The device displays the current speed in kilometres per hour on the vehicle's instrument dashboard. These days all cars are factory fitted with common device, but in the early 1900s, it was an expensive option.

  • Sound level meter

This device measures the intensity of noise/sound. The instrument is basically a microphone that picks up sound and converts it into an electrical signal which can be measured by a meter that is calibrated to read the sound level in decibels (a unit to measure sound intensity). If the decibel level of zero is the average threshold of hearing, then 120 decibels represents extremely loud sound that is painful to the human ear. Sound level meters are used frequently in some work places to provide sound information relating to prevention of deafness from excessive noise.

  • Light meter (photography)

This device is used to measure the amount of light that is ideal for use in photography. It is an excellent tool for photographers because it can accurately determine how much exposure is required for a photograph. This information can help the photographer to decide the correct camera shutter speed for the best exposure in certain lighting situations.

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What is UPI and how it works?

UPI saves people from Cash on Delivery hassle and running to an ATM

As Prime Minister Narendra Modi pushes for a digital India, many of us may have used Unified Payments Interface (UPI). But do you know what it is?

What is UPI?

UPI is a system that allows multiple bank accounts into a single mobile app, thus, merging several banking features, seamless fund routing, and merchant payments under one umbrella.

The UPI has made bank-to-bank money transfers simple and secure, enabling everything from purchasing vegetables from roadside vendors to sending money to friends and relatives.

UPI was launched by the National Payments Corporation of India (NPCI) on April 11, 2016, by Raghuram G Rajan, then-Governor of RBI, at Mumbai.


Some of the unique features of UPI is that it allows immediate money transfer through mobile phones round the clock 365 days.

Besides, it saves people from Cash on Delivery hassle, running to an ATM, or rendering exact amounts.

People can also pay multiple bills from a single mobile app via Utility Bill Payments, Over the Counter Payments, QR Code-(Scan and Pay) based payments.

As per the latest guideline issued by the NPCI, a person is allowed to use UPI to send a maximum of Rs 1 lakh per day. The restriction varies from bank to bank.

Besides, there is a cap on the total amount of UPI transfers that can be made in a day. Twenty transfers are permitted per day using UPI.


Steps for Registration

User downloads the UPI application from the App Store/  Bank's website

User creates his/her profile by entering details such as virtual id (payment address), password, etc. User goes to "Add/Link/Manage Bank Account' option and links the bank and account number with the virtual id

Generating UPI - PIN

User selects the bank account from which he / she wants to initiate the transaction

Change UPI PIN

User receives OTP from the Issuer bank on his / her registered mobile number

User now enters last 6 digits of Debit card number and expiry date

User enters OTP and enters his/her preferred numeric UPI PIN (UPI PIN that he/she would like to set) and clicks on Submit After clicking submit, customer gets notification (successful or decline) User enters his / her old UPI PIN and preferred new UPI PIN (UPI PIN that he/she would like to set) and clicks on Submit After clicking submit, customer gets notification (successful or failure)

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What does an extraterrestrial whirlwind sound like?

When the Perseverance rover successfully landed on Mars in February 2021, it marked the beginning of its tasks, which included looking for signs of past Martian microbial life, cache rock, and soil samples for future return to Earth. While the rover is still at it, it has provided for another first already. Based on data provided by Perseverance, scientists have made the first-ever audio recording of an extraterrestrial whirlwind.

Not always on

The Perseverance rover is equipped with what is the first working microphone on the Martian surface. This microphone, however, is not on continuously. Far from it, in reality. This microphone records for about three minutes every couple of days.

This is partly the reason why it has taken this long to get the whirlwind recording, despite the fact that the rover landed in the Jezero where there's been evidence of nearly 100 dust devils, or tiny tornadoes of dust and grit, since Perseverance landed.

This was the first time that the rover’s microphone was on when one of these dust devils passed over the rovers. While there is definitely an element of luck, it wasn't entirely unexpected as it was only a matter of time before the microphone was on at the right time.

"The Martian” might not happen

Taken along with air pressure readings and time-lapse photography, the sound recording of the dust devil will help scientists understand Mars atmosphere and weather conditions better. The information gathered has already suggested that future astronauts on the Martian surface would not have to worry about gale-force winds blowing down antennas or habitats, as popularised by The Martian, the book and the movie of the same name.

In fact, there is reason to believe that the winds might have certain benefits. Scientists believe that the winds blowing grit off the solar panels of other rovers like Opportunity and Spirit might well be the reason why they lasted so much longer. Similarly, the lack of such winds and dust devils in the Elysium Planitia where the Insight mission landed could be a factor as to why that mission's operational period was planned to end in December 2022.

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Moving objects using ultrasound waves

Using artificially engineering materials, researchers achieve contactless manipulation.

Have you heard about ultrasound? As the name suggests, ultrasound corresponds to sound waves with frequencies that are higher than the upper limit of what humans can hear. While we can't hear it, we still put it to good use, albeit in different ways.

One of the most popular ways, and one that you might have heard of, is to use ultrasound for scans. Ultrasound scans are a procedure whereby high-frequency sound waves are bounced off objects (think organs or bones) to create an image of part of the inside of the body. Commonly used to monitor the health of unborn babies during pregnancy, ultrasound waves are also employed to diagnose medical conditions.

Hands-free movement Researchers from the University of Minnesota Twin Cities have now discovered a new method that uses ultrasound waves to move objects. The study was published in Nature Communications early in December.

Even though waves have been shown to move objects before, these objects were typically very small, in the order of millimetres to nanometres. What the researchers of this study were able to achieve was to move bigger objects using ultrasound, backed by the principles of metamaterial physics.

What are metamaterials?

Materials that are engineered artificially to interact with waves such as light and sound are referred to as metamaterials. The researchers placed a metamaterial pattern on the surface of an object, which could then be steered without touches using sound.

The researchers were not only able to move an object forward using this technique, but were also able to pull it back towards the source. Even though the study only serves as a demonstration of a concept, higher frequencies of waves and different materials and object sizes are expected to be tested in the future.

The need to move things is ever-present in many fields of science and engineering, especially robotics. By exploring ultrasound waves to move objects without physical contact, the researchers have provided a new mechanism of contactless manipulation that might prove to be important in the upcoming years.

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What is Bokashi composting?

Bokashi composting provides an effective method of disposing kitchen waste. How is it done? Read on to find out.

Composting is the process of converting organic waste into fertilizer. Bokashi composting is one of the many techniques employed to achieve this.

Bokashi is Japanese for fermented organic matter. This fermenting process needs to be anaerobic, which means there should be no oxygen present during the fermentation.

Organic waste from the kitchen-leftover food, eggs, vegetable peels, even meat- is kept in an airtight container which has a tap at the bottom. A layer of waste is sprinkled with bokashi bran, a dry mixture containing beneficial microbes, and then covered with a plastic/steel plate. Another layer of waste is laid out over it, sprinkled and sealed. The same process is followed until the container is full.

Then the container's lid is closed and it is set aside for a few days for the fermentation to take place. The liquid released during fermentation is drained through the tap at the base.

Once the week is up, the contents of the container can be emptied in the garden. But the mixture shouldn't touch the roots of any plant yet. To become an effective fertilizer, the fermented matter needs to mix well with the soil for a couple of days..

Bokashi composting is popular because it takes up less space and provides an effective method of disposing kitchen waste. Also, during fermentation, the mulch in the container does not give out a bad odour.

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What kind of app is Destiny Lights?

Destiny Lights is a kind of social network in which users can explore ideas and exchange messages. Express your thoughts, ideas and anything you want to vent in the form of 'lanterns'. You can also anonymously post lanterns. These lanterns fly around the world, and fellow users can catch them and read your message. You can read other lanterns and like, save or leave a comment on them. The author will be able to receive and reply to comments on his/her lantern. The more likes it gets, the faster your lantern flies around and reaches different locations. If a lantern reaches 370 cities, it is included in the Top 50 lanterns in the app. If lantern in a foreign language, it has a built-in translator, too. The app also lets you find a you see how many people have read your update across the world. Free for Android.

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How does a foot mouse help disabled people?

The Foot Mouse by Califor Design is designed for people who are unable to use their hands due to disability or a neurological condition. Winner of the Red Dot Design Concept Award 2022, the Foot Mouse transfers control to the feet, allowing the user to navigate and click by resting a foot on it. The left and right keys are designed to be operated with the toes. The scrolling function is activated when the left and right buttons are simultaneously pressed, and deactivated when one of the left or right keys is released. "The concave design of the mouse's top surface is combined with human-machine engineering principles to ergonomically fit the complex curvature under the foot, ensuring a stable and comfortable user experience," says Califor Design. "Foot Mouse is designed to fit feet of any width and size and to provide anti-fatigue support for extended periods of use."

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What does a lightning rod do?

The lightning rod was invented by America's founding father Benjamin Franklin.

It protects buildings from lightning. It was invented by American scientist Benjamin Franklin who first proved that lightning and electricity were related, by conducting his fabled kite and key experiment.

The lightning rod is a pointed metal rod mounted on the roof of a building. It is electrically connected to the ground through a thick wire. When lightning strikes the building, the rod attracts the electric current and conducts it harmlessly to the ground through the wire. Thus, the lightning charge does not pass through the building where it could potentially start a fire or cause electrocution.


In the mid-18th Century, Benjamin Franklin flew a kite during a storm to see if a key attached to the string would draw an electrical charge. It did and this led to his invention of the lightning rod which protects tall buildings from lightning strikes.


Some monuments in the ancient Sri Lankan capital of Anuradhapura bear some of the earliest examples of metal lightning conductors.

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