Many of us have done this on exams, hoping for partial credit by stitching together the outline of a proof or using the right words in an essay with the hopes that the professor connects the dots for us.

Since water is denser than air, and the reflection is diffuse. A lot of light is internally reflected, thereof, increasing the probability of absorption at surface.

This is because the light now has a layer of water to go through. And due to the reflectance of water, not all light at the air-liquid-interface (border between air and water) goes through the water. Some of it is reflected.

There are two types of reflection (two ways the wave can be thrown back). Specular Diffuse

ericb 12 days ago | unvote [-] * Better googling. Time-restricted, url restricted, site restricted searches. Search with the variant parts of error messages removed.* Read the source of upstream dependencies. Fix or fork them if needed.* They're better at finding forks with solutions and gleaning hints from semi-related issues.* Formulate more creative hypothesis when obvious lines of investigation run out. The best don't give up.* Dig in to problems with more angles of investigation.* Have more tools in their toolbelt for debugging like adding logging, monkey-patching, swapping parts out, crippling areas to rule things out, binary search of affected code areas.* Consider the business.* Consider user-behavior.* Assume hostile users (security-wise).* Understand that the UI is not a security layer. Anything you can do with PostMan your backend should handle.* Whitelist style-security over blacklist style.* See eventual problems implied by various solutions.* "The Math."

technology diffused more easily along lines of latitude than along lines of longitude because climate changed more rapidly along lines of longitude making it more difficult for both humans and technologies to adapt

Anything that’s invented between when you’re fifteen and thirty-five is new and exciting and revolutionary and you can probably get a career in it.

"One of history’s few iron laws is that luxuries tend to become necessities and to spawn new obligations. Once people get used to a certain luxury, they take it for granted. Then they begin to count on it. Finally they reach a point where they can’t live without it.”

A 90s study showed that women preferred the scents of men whose immune systems were most different from their own immune-system genes. Evolutionarily this makes sense as, children should be healthier if their parents’ genes vary, protecting them from more pathogens.

Between 2011 and 2013, china used 50% more cement than the United States in the 20th century.Of the world’s 100 highest bridges, 81 are in China, including some unfinished ones.

Here’s Warren Buffett: “Cola has no taste memory. You can drink one at 9am, 11am, 5pm. You can't do that with cream soda, root beer, orange, grape. You get sick of them after a while. The average person drinks 64 ounces of liquid per day, and you can have all 64 ounces of that be Coke.”Same with Doritos, Cheetos, most popular junk food. They are engineered to overcome “sensory-specific satiety” and to give a sense of “vanishing caloric density.”

One of the tasks of true friendship is to listen compassionately and creatively to the hidden silences. Often secrets are not revealed in words, they lie concealed in the silence between words.

Video Games are a Booming IndustryThe video game industry generates more revenue than movies and music.

Humor treads at the frontier of consciousness. When a comic finds a funny joke, they are unearthing a truth that people are only kind of aware of, but the whole room grasps that everybody else is aware of the truth, and laughter ensues.

Highest Grossing Media Franchises

How the Sun Moves

“Twitter is the most amazing networking and learning network ever built.For someone whose pursuing their dream job, or chasing a group of mentors or peers, it’s remarkable. In any given field, 50-80% of the top experts in that field are on Twitter and they’re sharing ideas, and you can connect to them or follow them in your personal feed.If you get lucky enough and say something they find interesting, they might follow you, and the reason this becomes super interesting is that unlocks direct message, and now all of a sudden you can communicate directly or electronically with that individual. Very, very powerful.If you’re not using Twitter, you’re missing out.” — Bill Gurley

80% of Americans live, work, and hang out in the pink areas — 3.6 percent of the landmass of the lower 48 states.

"The easiest way to be discovered right now in technology and perhaps many fields is to create your own independent blog and write. There is a huge dearth in availability of good, current, first party content today.The single most important advice I can give to actually write is to write.The thing that happens which you don’t see until you write is that your content engages some of the smartest people who are lurking around the internet. And they reach out to you."

By some estimates, more than 50,000 pieces of artwork are stolen each year, amounting to annual losses of around $6 to $8 billion globally. This makes art theft one of the most valuable criminal enterprises around, exceeded only by drug trafficking and arms dealing.

Where is Wealth Concentrated?

This map shows the relative density of commercial shipping around the world. The darker the color, the busier the route.

I've noticed a weird pattern: In most of the best marriages I see, one person is an early-bird, and the other is a night-owl. They have opposite circadian rhythms.I think this is healthy. The two partners get the benefits of time together and time alone, which helps the marriage.

look around and figure out who you want to be on your team. Figure out the people around you that you want to work with for the rest of your life. Figure out the people who are smart & awesome, who share your values, who get things done — and maybe most important, who you like to be with and who you want to help win. And treat them right, always. Look for ways to help, to work together, to learn. Because in 20 years you’ll all be in amazing places doing amazing things.

It goes completely against what most believe, but out of all major energy sources, nuclear is the safest

Studies show it takes ~23 minutes to deeply refocus on something when you get disturbed

if you care at all about storing timestamps in MySQL, store them as integers and use the UNIX_TIMESTAMP() and FROM_UNIXTIME() functions.

The system clock is inaccurate. You're on a network? Every other system's clock is differently inaccurate.

A time format without an offset is useless.

If you want to store a humanly-readable time (e.g. logs), consider storing it along with Unix time, not instead of Unix time.

When storing a timestamp, store Unix time. It's a single number.

Most of your code shouldn't be dealing with timezones or local time, it should be passing Unix time around.

Unix time: Measured as the number of seconds since epoch (the beginning of 1970 in UTC). Unix time is not affected by time zones or daylight saving

GMT is still used: it's the British national timezone in winter. In summer it becomes BST.

Australian Eastern Standard Time is UTC+1000. e.g. 10:00 UTC is 20:00 EST on the same day.

GMT: UTC used to be called Greenwich Mean Time (GMT) because the Prime Meridian was (arbitrarily) chosen to pass through the Royal Observatory in Greenwich.

UTC: The time at zero degrees longitude (the Prime Meridian) is called Coordinated Universal Time (UTC is a compromise between the French and English initialisms)

we shield ourselves from existential threats, or consciously thinking about the idea that we are going to die, by shutting down predictions about the self,” researcher Avi Goldstein told The Guardian, “or categorizing the information as being about other people rather than ourselves.

test of whether they know how to look for help.Are they able to read a manual?Can they formulate a search query?How do they assess whether the tutorial they found is suitable or reliable?What steps do they take to make sure they're finding - and learning - the right information?

Zugzwang (German for "compulsion to move", pronounced [ˈtsuːktsvaŋ]) is a situation found in chess and other games wherein one player is put at a disadvantage because they must make a move when they would prefer to pass and not move

Today, my process is enjoyably unsophisticated. When I want to post something, I first write it in a text file, copy my last blog post’s HTML file, paste in my new article, make some slight adjustments, update my list of posts, add it to my RSS file, and that’s basically it. Any page on my website can be anything I want it to be, like how, for example, double clicking on this article leads to a small easter egg.

walking, cycling and more green spaces not only cut air pollution but also improved mental health.

“Although the studies included were from different parts of the world – eg China, the US, Germany – and varied in sample size, study design and measures of depression, the reported associations were very similar.”

The studies analysed took account of many factors that might affect mental health, including home location, income, education, smoking, employment and obesity. But they were not able to separate the potential impact of noise, which often occurs alongside air pollution and is known to have psychological effects.

more than 90% of the global population lives with air pollution above WHO-recommended levels

People exposed to an increase of 10 micrograms per cubic metre (µg/m3) in the level of PM2.5 for a year or more had a 10% higher risk of getting depression.

The data analysed in the new research linked depression with air pollution particles smaller than 2.5 micrometres (equivalent to 0.0025 millimetres and known as PM2.5)

Other research indicates that air pollution causes a “huge” reduction in intelligence and is linked to dementia. A comprehensive global review earlier in 2019 concluded that air pollution may be damaging every organ and virtually every cell in the human body.

the finest particulates from dirty air can reach the brain via both the bloodstream and the nose, and that air pollution has been implicated in increased [brain] inflammation, damage to nerve cells and to changes in stress hormone production, which have been linked to poor mental health,” Braithwaite said

“You could prevent about 15% of depression, assuming there is a causal relationship. It would be a very large impact, because depression is a very common disease and is increasing.” More than 264 million people have depression, according to the WHO.

Depression and suicide linked to air pollution in new global study Cutting toxic air might prevent millions of people getting depression, research suggests

Nothing truly novel, nothing that matters, is ever learned with ease

Leaders in every sector seem to agree: Learning is an imperative, not a cliché. Without it, careers derail and companies fail.

Unit Testing

End-to-End Testing

Integration Testing

There are three different methods of Automated Testing

The major selling point of Julia these days is in crafting differentiable algorithms (data-driven code that neural networks use in machine learning) in Flux (machine learning library for Julia)

I decided that the name of the game is to optimise quality of life. That means, infrequent brutal deadlines, minimal (pref. zero) commute, opportunity to learn, and spend time with family and friends and be of use to society at large.

My mom is the best example of how to enjoy life in the present. She takes her work seriously, but doesn't take herself too seriously, and by putting fun first, every accomplishment and accolade is merely a bonus

But we can take steps to control and lower our stress levels and, as a result, our arousal. Techniques like consciously controlling your breathing, and listening to chilled music have been known to help. More traditional advice, like reducing how much coffee you drink, eating a balanced diet and getting enough sleep each night should also be helpful

In our third study, we had 169 participants jog on the spot for 60 seconds. We found that these participants were more likely to share embarrassing stories – or open up to others – after physical exercise. Usually, people might disclose personal information like this to people that are close to them, but it seems we are more likely to open up to strangers when aroused, particularly by physical exercise

Information that we’re usually careful about disclosing, like secrets and very personal information, are more likely to be disclosed when we default to more automatic responses; mainly because they require some degree of effort to conceal.

At some point, we replaced the order of displaying the superpower packs (SP) from ascending to descending

Users don’t appreciate it when you try to trick them out of their money, or when they think you are doing that. A better approach would be to give them the opportunity to get what they want for free (even with a lot of work involved), and give an alternative purchase option. In this case the purchase will be perceived as a small cheat to make life easier instead of a shady scheme to get users to pay

There were four packs respectively containing 25, 50, 150 and 500 superpowers. We increased the biggest power pack from 500 to infinity. Practically, nothing changed. 500 superpowers were more than enough for the entire game, and very few users had spent all of it. However, after the change was made, the revenue from this pack grew by 50%

I observed a similar effect in my own business when I was producing and selling metal license plates (sold via partner brick-and-mortar stores and through our own online store). At the start, the prices we set were relatively low ($3-5). But in a few months, we raised the prices by 2-3 times, and the plates then cost $15-25. Contrary to our expectations, the conversion rate almost doubled, as well as the average order amount.

With a vitamin C priced at $3, 100% of participants experienced relief. But the drug priced at $0.1 only worked in 50% of cases

The word “free” makes any product more attractive to its potential customers. If you have a way to distribute your product for free, at least partially (a trial option, a limited version), then make sure to use it. This approach will greatly expand the top of your funnel. Once done, you will simply have to learn how to convert these new users into the paying ones

I decided to compare how those who got it for free and those paid for it went through the levels in the game. There was a hypothesis that those who got it for “free” should stop using the game faster and sooner than those who paid for it. The hypothesis turned out to be wrong. The users of both the free and the paid version had identical behavior in the first 40 levels However, after level 40, the “free” players started quitting the game much faster. I interpreted this as those who received the game for free appreciated it less, so their motivation to go till the end or return to it after a couple of days was less

When we make decisions, our perception is influenced by a lot of factors such as presentation, packaging, brand, opinions of people around us, experts’ opinions, our own expectations, etc. Each of these factors can ultimately determine how much a person will like your product and how much she will be willing to pay for it

In one case, the participants were given brochures describing the capabilities of a new audio system. The only difference between the brochures was that the first one was published on behalf of the system’s manufacturer and the second one on behalf of an independent research center. The participants who had seen the second brochure were willing to pay twice as much as the first group for the audio system

those who received coffee when the table was beautifully set appreciated the taste way more, and were also ready to pay more for it

Joshua Bell, one of the best concert violinists in the world played for free, for 45 minutes, on a violin worth $3.5 million dollars at a subway station. He managed to raise $32. Most people (98%) who passed by paid no attention to him, only 2% gave him some money, and less than 0.5% stopped to listen (those were the people who actually recognized him)

If you want to change the rules of the game in a field that you are about to enter, try to portray your product as something new and different. Doing so will enable you to set the rules of the game from scratch and be the first one to establish the anchor. And when you install the anchor, do not lower the price; there will still be time for that (making a discount always sounds better than raising the price)

When the sales agents of a health insurance company that was selling its services via phone asked people (who agreed to proceed) why they chose their company, the proportion of those who eventually decided to purchase the insurance increased significantly. As they thought about the answer to this question, the respondents subconsciously convinced themselves that they had made the right choice, further strengthening their decision and eventually leading to their making the purchase

People also tend to form new “rules” when they encounter something for the first time. Starbucks is very different from other coffee stores. Therefore, when interacting with them, people create new rules instead of resorting to existing patterns

we tend to base our decisions on things we’ve experienced before, to make decisions easier

It is difficult to find a logical explanation for this, but apparently the prices that end with 9 trigger some kind of automatic mechanism

Offering to proceed with a $1 per day tariff and the one that costs $350 per year are mathematically equivalent, but trigger different reactions in customers. The first option can be compared to purchasing a water bottle in a grocery store, and the second option is more like purchasing a mobile phone

Mathematically equivalent statements are not necessarily equivalent psychologically

Do not lower prices. The price that you declare at the very beginning will become the reference point. You can also try to show your customers big numbers before starting to talk about the money

people are guided by the available prices to assess the rest of the offered goods

Salesmen in retail stores try to sell the most expensive things first, or at least offer them to customers. For instance, a person who came to buy a suit is first shown the suits. When the customer makes his choice, then the salesperson suggests appropriate accessories, such as a tie to go with the suit. Compared to the suit’s price, the tie looks very inexpensive and is an easy upsell

We rarely think in absolute terms, and we don’t have a universal measure to understand the value of a certain thing. Therefore, we tend to evaluate things by comparing them to others

The lack of a ready-made pattern of behavior makes people rely on “simple” factors in decision-making (such as other people’s behavior, template principles, pre-designed baits, etc.), rather than the correct ones

The circles drawn in the center of the image above are identical. But depending on their environment, their perceived size changes

New study shows that our personal memories might not be personal at all. All it takes to change your memories is thinking about a different person, and considering how they would approach what happened to you. Perhaps our character isn’t as unique as we think, but more fluid, and changed by every person we meet. Our evaluation of ourselves changes even when we think of objects, not just other people

if your goal is to build a remarkable life, then busyness and exhaustion should be your enemy

Hard work is deliberate practice. It’s not fun while you’re doing it, but you don’t have to do too much of it in any one day (the elite players spent, on average, 3.5 hours per day engaged in deliberate practice, broken into two sessions). It also provides you measurable progress in a skill, which generates a strong sense of contentment and motivation

The elite players were spending almost three times more hours than the average players on deliberate practice

The average players, they discovered, spread their work throughout the day. A graph included in the paper, which shows the average time spent working versus the waking hours of the day, is essentially flat. The elite players, by contrast, consolidated their work into two well-defined periods

the elite players slept an hour more per night than the average players

the elite players were significantly more relaxed than the average players, and the best of the best were the most relaxed of all

the more files you have and the bigger your project, the more resources VS Code will start to consume. The Search Indexing and File Watcher scripts start eating up your memory. Moreover, to work on such a project, you will open each file in a new tab, leading to multiple VS Code instances running simultaneously, and eventually, your CPU usage will start to look like this

FKs don't work well with online schema migrations.

FKs are a performance impact. The fact they require indexes is likely fine, since those indexes are needed anyhow. But the lookup made for each insert/delete is an overhead.

FKs are in your way to shard your database. Your app is accustomed to rely on FK to maintain integrity, instead of doing it on its own. It may even rely on FK to cascade deletes (shudder). When eventually you want to shard or extract data out, you need to change & test the app to an unknown extent.

To grow, trees photosynthesize and turn water and carbon dioxide (pulled from the air), into hydrocarbons. A living tree sucks carbon dioxide from the air and locks it into wood as it grows. Even when the tree dies (unless we burn it), the carbon is still locked up in the wood

For a wood fire, ash is primarily composed of metal carbonates and oxides (such as Calcium Carbonate, and Potassium Carbonate), from the compounds in the original wood

As long as there is a source of fuel (and oxygen), the fire will burn

As the fire gets hotter, more complete combustion occurs, less smoke is produced, and the flames lose the yellow color, turning more blue

yellow flames seen in a fire are the result of incomplete combustion

smoke produced (early stages of fire) is unburned carbon

It is the volatile compounds that out-gas from the wood, and eagerly react with oxygen, that are burning, and generate the flames we see

When the temperature of wood is increased (through application of heat), first the water is driven off. This occurs up to about 200°C. Between approximately 200°C–280°C the heat starts to break down the hemicellulose compounds into Carbon Monoxide, Carbon Dioxide, Acetic Acid, (and more water vapour); these are driven out. Between 280°–500° decomposition of the longer cellulose and lignin begins and produces light tars and Methyl Alcohol

A couple of hundred intermediate products (organic acids, ketones, esters, aldehydes …) have been identified as being produced by the pyrolysis of wood

The pyrolysis of wood is an incredibly intricate and complex process that is not completely mapped out and the exact output depends of many variables

The correct term to describe what is going on when we ‘burn’ wood is Pyrolysis

The chemical composition of wood varies from species to species, but is approximately 50% carbon, 42% Oxygen, 6% Hydrogen, 1% Nitrogen, and 1% other elements (mainly Calcium, Potassium, Sodium, Magnesium, Iron, and Manganese) by weight

Wood is the hard-fibrous material that comes from the trunk, stems, roots, and branches of a once living tree

To boil everything down to a bullet list, the differences Firefox Developer Edition bring to the table include: A separate profile so your development environment can be configured differently to your regular browsing environment Access to cutting edge features not available elsewhere A 12 week lead time on support for the newest additions to web standards Default preferences tuned for developers Dark theme style out of the box

“Why don’t you assume you’ve written your book already — and all you have to do now is find it?”

Here’s Stephen Harrigan (talking about his book, Big Wonderful Thing: A History of Texas)

In my experience writing books, it isn’t just a “resistance” thing or a “perfectionist” thing or a fear thing, it’s more about research and wondering if you’ve done enough of it. Research becomes your way of procrastinating, because, let’s face it, research is just more fun than writing. (Me, personally, I became a professional writer so I could be a professional reader.)

There’s an awful temptation to just keep on researching. There comes a point where you just have to stop, and start writing. When I began, I thought that the way one should work was to do all the research and then write the book. In time I began to understand that it’s when you start writing that you really find out what you don’t know and need to know.

great place to start finding circuit schematic is the Discover Circuits site. They have a comprehensive list of fun circuits to experiment with

Step 19: Your Third Circuit

Step 18: Your Second Circuit

Step 17: Your First Circuit

designed to allow you to be able to insert an integrated circuit into the center

To use wire in your circuit, simply cut a piece to size, strip a 1/4" of insulation from each end of the wire and use it to connect points together on the breadboard

When things are wired in parallel, they are wired side by side, such that electricity passes through all of them at the same time, from one common point to another common point

When things are wired in series, things are wired one after another, such that electricity has to pass through one thing, then the next thing, then the next, and so on

circuit is a complete and closed path through which electric current can flow

electricity is typically defined as having a voltage and a current rating

it is recommended that you use insulated 22awg (22 gauge) solid core wire

Wires are nice because they allow you to connect things without adding virtually no resistance to the circuit

there typically runs two continuous bus lines. One is intended as a power bus and the other is intended as a ground bus

They are covered with a grid of holes, which are split into electrically continuous rows. In the central part there are two columns of rows that are side-by-side

Breadboards are special boards for prototyping electronics

Batteries are represented in a circuit by a series of alternating lines of different length

battery is a container which converts chemical energy into electricity

This is dependent on the type of switch it is

switch is basically a mechanical device that creates a break in a circuit. When you activate the switch, it opens or closes the circuit

it is ideal to light up multiple LEDs by wiring them in parallel

Like all diodes, LEDs create a voltage drop in the circuit, but typically do not add much resistance

special type of diode that lights up when electricity passes through it. Like all diodes, the LED is polarized and electricity is only intended to pass through in one direction

For instance, if you have two 10K resistors in series between power (5V) and ground (0V), the point where these two resistors meet will be half the power supply (2.5V) because both of the resistors have identical values

current is rated in Amps

integrated circuit is an entire specialized circuit that has been miniaturized and fit onto one small chip with each leg of the chip connecting to a point within the circuit. These miniaturized circuits typically consist of components such as transistors, resistors, and diodes

PNP transistors allow electricity to pass from the emitter pin to the collector pin

NPN transistors allow electricity to pass from the collector pin to the emitter pin

transistor takes in a small electrical current at its base pin and amplifies it such that a much larger current can pass between its collector and emitter pins. The amount of current that passes between these two pins is proportional to the voltage being applied at the base pin

the other side connects to power

The ring found on one end of the diode indicates the side of the diode which connects to ground

Diodes are components which are polarized. They only allow electrical current to pass through them in one direction. This is useful in that it can be placed in a circuit to prevent electricity from flowing in the wrong direction

Ceramic disc capacitors are non-polarized, meaning that electricity can pass through them no matter how they are inserted in the circuit

Electrolytic capacitors are typically polarized. This means that one leg needs to be connected to the ground side of the circuit and the other leg must be connected to power. If it is connected backwards, it won't work correctly

capacitor is a component that stores electricity and then discharges it into the circuit when there is a drop in electricity

With alternating current, the direction electricity flows throughout the circuit is constantly reversing

resistors add resistance to the circuit and reduces the flow of electrical current. It is represented in a circuit diagram as a pointy squiggle with a value next to it

electricity in a circuit must be used

With Direct Current, electricity flows in one direction between power and ground

Potentiometers are measured in ohms like resistors, but rather than having color bands, they have their value rating written directly on them (i.e. "1M"). They are also marked with an "A" or a "B, " which indicated the type of response curve it has

Potentiometers are variable resistors. In plain English, they have some sort of knob or slider that you turn or push to change resistance in a circuit. If you have ever used a volume knob on a stereo or a sliding light dimmer, then you have used a potentiometer

The round notch on one edge of the IC chip indicates the top of the chip. The pin to the top left of the chip is considered pin 1. From pin 1, you read sequentially down the side until you reach the bottom (i.e. pin 1, pin 2, pin 3..). Once at the bottom, you move across to the opposite side

As a beginner, you will be mainly working with DIP chips. These have pins for through-hole mounting. As you get more advanced, you may consider SMT chips which are surface mount soldered to one side of a circuit board

you can learn all about integrated circuits by looking up their datasheets. On the datasheet you will learn the functionality of each pin. It should also state the voltage and current ratings of both the chip itself and each individual pin

There are two basic types of transistors, which are NPN and PNP

They are represented in schematic as a line with a triangle pointing at it

it requires energy to pass through a diode and this results in a drop of voltage. This is typically a loss of about 0.7V

The most commonly encountered types of capacitors are ceramic disc capacitors that look like tiny M&Ms with two wires sticking out of them and electrolytic capacitors that look more like small cylindrical tubes with two wires coming out the bottom (or sometimes each end)

Capacitors are measured in Farads

Any resistor of over 1000 ohms is typically shorted using the letter K. For instance, 1,000 would be 1K

Anyhow... a resistor with the markings brown, black, orange, gold will translate as follows: 1 (brown) 0 (black) x 1,000 = 10,000 with a tolerance of +/- 5%

You read the values from left to right towards the (typically) gold band

two different ways in which you can wire things together called series and parallel

switch does not add any resistance to a circuit and simply adding a switch between power and ground will create a short circuit

Always make sure that you never accidentally connect positive voltage to ground while wiring things in parallel

electricity always follows the path of least resistance to ground

It is very important to prevent short circuits by making sure that the positive voltage is never wired directly to ground

Shorts are bad because they will result in your battery and/or circuit overheating, breaking, catching on fire, and/or exploding

there needs to be something wired between positive and ground that adds resistance to the flow of electricity and uses it up. If positive voltage is connected directly to ground and does not first pass through something that adds resistance, like a motor, this will result in a short circuit

Voltage is obviously rated in Volts

There are two types of electrical  signals , those being alternating current (AC), and direct current (DC)

The rate of reversal is measured in Hertz, which is the number of reversals per second

The result of the uniform interface is that requests from different clients look the same, whether the client is a chrome browser, a linux server, a python script, an android app or anything else

The client can request code from the server, and then the response from the server will contain some code, usually in the form of a script, when the response is in HTML format. The client then can execute that code

data the server sends contain information about whether or not the data is cacheable. If the data is cacheable, it might contain some sort of a version number. The version number is what makes caching possible: since the client knows which version of the data it already has (from a previous response), the client can avoid requesting the same data again and again

In order for an API to be RESTful, it has to adhere to 6 constraints

there might be a number of servers in the middle. These servers might provide a security layer, a caching layer, a load-balancing layer, or other functionality

Stateless means the server does not remember anything about the user who uses the API

client and the server act independently, each on its own, and the interaction between them is only in the form of requests, initiated by the client only, and responses, which the server send to the client only as a reaction to a request

Uniform interface

What the server does when you, the client, call one of its APIs depends on 2 things that you need to provide to the server

The representation of the state can be in a JSON format, and probably for most APIs this is indeed the case. It can also be in XML or HTML format

It means when a RESTful API is called, the server will transfer to the client a representation of the state of the requested resource.

RESTful web application exposes information about itself in the form of information about its resources. It also enables the client to take actions on those resources, such as create new resources (i.e. create a new user) or change existing resources (i.e. edit a post).

A single on/off decision is best understandable using a toggle switch.

A single yes/no option is more usable with a checkbox.

Independent items use toggle switches for selection.

To select related items in a list, use checkboxes.

Sometimes toggle switch does not clearly indicate whether it is a state or action.

Indeterminate state is best shown using a checkbox

Selecting multiple options in a list provides better experience using checkboxes.

Checkboxes are preferred when an explicit action is required to apply settings.

The options that require instant response are best selected using a toggle switch.

The children watched an educational video that included clips from Sesame Street and covered math topics such as counting and addition as well as reading topics for comparison

boys and girls as old as 8 had similar abilities when it came to perceiving numbers and grasping elementary mathematics concepts