The Covid-19 pandemic has highlighted the importance of our healthcare systems in an unprecedented way. Many of us have had firsthand experience of the care and dedication of health workers over the last 18 months. They have proven an inspiration, in more ways than one.
Many individuals have been invigorated by their example to pursue careers in the healthcare sector, a varied and exciting area that is constantly developing in accordance with the latest technological and scientific breakthroughs. If you’re been inspired to choose a career in healthcare, then check out these exciting opportunities, selected from the Alison Career Guide.
A healthy diet is one of the most effective preventative medicines available. Good nutrition boosts your immune system and helps protect you from all manner of illnesses, as a good diet means you’re better prepared to fight infection. Dietitians have the joy of helping patients enact changes in their eating habits that can truly alter their lives. You’ll also find yourself with opportunities to work in a wide variety of exciting sectors besides healthcare, such as sports and catering. Our Diploma in Human Nutrition is the perfect place to start your training in this rewarding career.
The local GP is a community cornerstone. Besides offering medical advice to the community, their presence also provide assurance and stability. This makes being a GP an exceptionally satisfying job, though a demanding one. GPs need to have expertise across all fields of medicine in order to be able to accurately diagnose their patients. We have hundreds of essential healthcare courses to help you build up your medical expertise but the best place to start your GP journey is with our Diploma in Human Anatomy and Physiology.
While doctors, nurses and other frontline medical staff are the public face of the healthcare sector, there are hundreds of other careers that are vital for this industry to operate effectively. A hospital is an organisation like any other and is incredibly complicated to run. Health Service Managers thus need to be efficient, organised and trained in the latest management skills and software. By taking our SAP ERP Logistics Overview course, you’ll learn the skills you need to coordinate the various moving parts of a healthcare institution.
The job of an Emergency Medical Technician is a hard one. But it’s also exhilarating and inspiring. As a first responder you need to be calm, confident and prepared for all eventualities. Emergency Medical Technicians often speak of having a vocation to help others, and this devotion to your work is a must. If you’ve got the commitment, then the next step is to take our free course in CPR, AED and First Aid, which will give you a great foundation for this worthwhile career.
A Head Nurse has to juggle all of the usual medical demands of hospital work, while also managing their team to ensure patients receive the best care and appropriate attention. You’ll need to be compassionate and coordinated, caring and organised to successfully navigate this career. Head Nurses don’t just have to care for their patients, they also have to monitor the wellbeing of their nursing team, to make sure that they’re coping with this often high stress profession. Our Diploma in Clinical Nursing Skills will set you on the right track to becoming the perfect Head Nurse.
If you’re interested in building mobile apps, you’ve probably heard of React Native. The open-source framework took mobile development by storm after it was released by Facebook in 2015.
Today, most people browse the Internet on a mobile device instead of a desktop, so it’s important that businesses have a mobile presence. The best way to do this is with a mobile app. Unlike standard websites, mobile apps allow businesses to communicate directly with their customers through notifications and messages.
Traditional mobile app development requires the knowledge of two separate platforms (and their associated programming languages): Android and iOS. But, with React Native, you can develop hybrid applications that run on both.
In this article (and in the video below), we go into more detail about React Native, how it works, and what it can do for your mobile development projects.
How React Native works
React Native makes it easy to develop mobile applications that run on both Android and iOS. When running a React Native app on either platform, it looks and acts exactly the same. If you were to compare them side by side, you’d see that:
The app looks and feels almost identical on either phone.
The user interface is consistent.
The scrolling and searching work the same.
As Mike, a developer from Philadelphia, explains in the video above:
“The Android version acts and responds the way you’d expect an Android app to act and respond. We can use the back button. We get the same scrolling effects and animations Android users have come to expect. And the app will use whatever keyboard the user has set for searching.”
With regards to the app running on iPhones, Mike added:
“The iPhone version is the same. It acts and responds the way iPhone users would expect and integrates with the gestures and actions that those users are used to.”
Now, this may not seem surprising at first. If you’re a business, you want to develop iPhone as well as Android apps. You also want them to look and act the same. The surprising thing is that this normally would involve building two separate apps using totally different programming languages. But with React Native, it doesn’t.
With React Native, you can use the same technologies and programming languages used for web development. As a JavaScript framework, it lets developers build mobile apps that run on both iOS and Android using a single JavaScript codebase.
React Native apps act just like the native apps you could build separately for each device. These apps can also be sold through the App Store or Google Play, just like their native counterparts. They’re also just as fast and efficient as native apps and automatically integrate with native devices.
The story of React Native
When React Native was first released, it had an enormous impact on the mobile development community. It was groundbreaking. No longer did you need specialized Android and iPhone developers. A Web Developer could now build a complete mobile app using one codebase.
After recognizing how it made mobile app development so much easier, Mobile Developers and businesses immediately started using React Native. It also lowered the barrier to entry, as web development teams could now build mobile apps with only a little extra training.
You can find React Native in many of the apps you use every day. Some mobile apps that use React Native include:
Facebook
Instagram
Pinterest
Uber
Coinbase
Shopify
Discord
Despite this widespread usage of React Native by tech companies, both big and small, it’s still a relatively new technology. The React Native framework was first announced at Facebook’s ReactJS conference in 2015 and was released to the public later that year. The engineers behind its development based it on Facebook’s existing JavaScript web development framework, React.
React Native is still maintained today by a core group of developers at Facebook, but a lot of its direction is guided by the open-source development community behind it. It’s currently one of the most popular open-source projects of any type on Github, is completely free to use, and has a development community reaching millions.
React Native’s popularity is a testament to how fast and easy it makes building mobile apps for both Android and iOS.
Getting started with React Native
Now that you see how easy React Native can make your mobile development process — want to know more?
You don’t have to know the Android programming languages, Java and Kotlin, or the Apple programming languages, Objective-C and Swift, to develop apps with React Native. But, it does require knowledge of the JavaScript programming language, which you can pick up in our Learn JavaScript course.
You’ll also need to know the React JavaScript framework, which you can learn in our Learn React course. Of course, you can get started right away with Learn React Native if you already know these technologies. This course will teach you how to use Expo along with React Native to create a complete mobile app that runs on both an iPhone and an Android phone.
Modern web applications are quite different from those we had a few decades ago. Older web applications did all the data processing on the server and returned a static web page to the user when it was done. When you submitted a web form, it would require your browser to load a new page to get your results.
Modern web apps make this process seamless by handling data processing, rendering, and retrieval in the browser itself — making the user experience seamless without unnecessary page loads. This is done with JavaScript and, in most cases, with front-end frameworks like Angular.
Below, we’ll take a closer look at front-end frameworks, Angular and some of its defining features, how Angular compares to React, and more.
What is a front-end framework?
A front-end framework makes building and maintaining a front-end web application quicker and easier by providing structure and reusable components and code to a development project.
Frameworks take the burden of creating a structure for an application off of developers by providing a set of standards for development. Since these frameworks are well-known, new developers can get started right away with a familiar framework instead of struggling with a custom application.
Front-end frameworks also provide reusable JavaScript components and code that developers can use in their applications.
What is Angular?
AngularJS was one of the first modern JavaScript front-end frameworks. It came to market in 2010 and rapidly became the most popular JavaScript MVC (Model-View-Controller) framework.
AngularJS quickly became popular because of features like dependency injection, routing, and two-way data binding. It significantly changed how Front-End Developers wrote code. Five years later, Angular 2 (or Angular) was released. Unlike AngularJS, which is written in JavaScript, Angular is written in TypeScript.
Until Angular’s release, jQuery was the main JavaScript library most developers used for front-end web development. This was because jQuery made manipulating the DOM (Document Object Model) of a web page simple and easy across different browsers. Still, its non-binding structure often led to spaghetti code.
Angular adds structure and design patterns to front-end development, allowing developers to create more advanced web applications that are easier to maintain and update.
MVC in Angular
MVC is a code pattern with a long history, and it’s used by many frameworks — both front-end and back-end. In Angular, a web application is broken up into these three parts:
Model. The model represents the data that populates a web page. This data may eventually be stored in a database. For example, a user profile form will have a model of the user’s data in the memory that gets updated both by the form and API calls to a web server.
View. The view is the UI (user interface), or what you see in the browser. It represents the data in the model to the user in a viewable format.
Controller. The controller contains the logic for the web application. When a user saves data in a form, it’ll make the API call to update the data on a server. When a user refreshes the page, an API call retrieves that data from the server and updates the view with the new data.
Routing in Angular
Applications built with Angular are called Single Page Applications (SPAs). SPAs run in a web page without requiring a page reload but require a URL to function. Routing is what translates the URL in the web browser to a specific state in the web app.
So, when you go to http://example.com/users, Angular parses this URL, determines that the view you want is the list of users, and then presents that view. The URL is different than http://example.com, and the same page is loaded, but Angular generates a different view.
Traditionally, in back-end web applications, this URL would be parsed by the web server, which would then determine what page would be generated for this URL and return it to the user.
Two-way data binding
Angular uses two-way data binding, which means the data model and the view are inherently linked. Updating one updates the other. Here’s an example in code:
Enter Your Name:
Hello
In the code above, ng-app is what’s called a directive in Angular. It tells Angular that this is the root element for the application.
Below that, we have an input field. It has a directive called “ng-model” that binds the input field’s value to the name variable. When you enter any value in the field, the name gets updated to the contents of the field.
Below that, there’s a label with the “ng-bind” directive. This directive tells Angular to replace the content of the label element with the value of the name variable. This means that as you type in the form, the value of the label will update in real-time with each character change.
What’s the difference between Angular and React?
Both Angular and React are popular front-end JavaScript frameworks, but they do things slightly differently. The biggest difference is that Angular is actually a complete front-end MVC framework while React, though it’s been called a framework, is a JavaScript library for creating user interfaces in web apps.
In other words, React only covers the V (view) part of MVC. For the M (model) and C (controller) parts, you’ll have to use other JavaScript libraries.
Another difference between React and Angular is that Angular interacts with the real DOM (Document Object Model) of a web page. When the data updates, Angular changes what you see on the page.
React, on the other hand, interacts with the virtual DOM — a lightweight copy of the real DOM — and has no power to update what a user sees on the screen. With React, when data updates on a web page, the virtual DOM is updated, the differences between the real DOM and the virtual DOM are compared, and only those differences are updated in the real DOM.
Angular also uses two-way data binding, and React only allows data to flow in one direction. Two-way data binding means that when a user updates data on a page, like with a web form, it’s immediately updated in the data model. And, when the data model is updated from an API call, it’s immediately updated in the view. When a user interacts with a form in React, it updates the data model and then updates the view.
How to get started with Angular
Now, you’ve got a basic idea of why Angular is one of the top JavaScript front-end frameworks in use today. Knowing how to develop web apps in Angular is a skill that’s in very high demand.
If you’re ready to start using Angular, check out our Learn AngularJS course. If you’re new to programming in JavaScript, taking our Learn JavaScript course will prepare you by teaching you the fundamentals of the programming language that powers Angular.
I love the coziness of this October landscape and the warm grays & browns color palette it creates. It makes me feel like cuddling up in front of a crackling fire wrapped in a comfy blanket. There’s nothing more earthy and warm than grays paired with browns. This color combination is very versatile in design and allows for the flexibility of adding different pops of color but can also stand as a strong palette alone.
Warm Grays & Browns Color Palette
Below I have created for you a simple mood board featuring today’s color combination. It is in perfect Pinterest format, so feel free to pin it for later.
See our collection of other gorgeous color palettes by visiting our color palette section.
What do you think about our Warm Grays & Browns color palette? Do you like such monochromatic and simple combinations? I’m usually a fan of at least one contrasting color in the plate however there are lots of crafts that look perfect when the colors are soft and subtle.
We would love to hear your thoughts, so make sure to share them in the comments below.
Lastly, learn about the power of color in blog design in our blog post to see how important colors are in all the projects you create.
If you like this color palette, make sure to grab this month’s free Wallpaper! Only until the end of this month, it is available for free.
There is simply no shortage of blog design possibilities when it comes to bringing this pretty color palette to life.
A recent Times article about college football describes 2021 as “the ultimate year of homecomings” after schools from coast to coast either didn’t play at all in 2020, or couldn’t play on their own fields.
Are sports back at your school this year? Are you excited to play — or watch? Have rules been added to make sure practices and games are safe, or are conditions more or less like they were in 2019?
Put your thoughts in the comments, then read the related article to learn more.
Learn more about Picture Prompts here and find all of our prompts in this column.
Students 13 and older in the United States and the United Kingdom, and 16 and older elsewhere, are invited to comment. All comments are moderated by the Learning Network staff, but please keep in mind that once your comment is accepted, it will be made public.
To old friends who met him backstage, he was Pete Ventantonio, a punk rocker from Bridgewater, N.J. On his records, he sometimes preferred whimsical credits like Marcello DiTerriclothia or Favorite Singer Who Goes With Everything.
… The group’s self-mythologizing sometimes made its history murky. Even the name Jack Terricloth has various apocryphal origin stories. Mr. Cavallaro recalled his friend acquiring it from an old girlfriend. Others said he took the name to distinguish himself from another Pete during his early days in the New Jersey punk demimonde.
The ultimate reason seemed to matter less than the act of self-reinvention, and his audience’s being in on the act.
Daily Word Challenge
Can you correctly use the word apocryphal in a sentence?
Based on the definition and example provided, write a sentence using today’s Word of the Day and share it as a comment on this article. It is most important that your sentence makes sense and demonstrates that you understand the word’s definition, but we also encourage you to be creative and have fun.
Then, read some of the other sentences students have submitted and use the “Recommend” button to vote for two original sentences that stand out to you.
If you want a better idea of how apocryphal can be used in a sentence, read these usage examples on Vocabulary.com.
Students ages 13 and older in the United States and the United Kingdom, and 16 and older elsewhere, can comment. All comments are moderated by the Learning Network staff.
In an article from June, “Disputing Racism’s Reach, Republicans Rattle American Schools,” Trip Gabriel and Dana Goldstein describe how a culture-war brawl has spilled into the country’s educational system, and how Republicans at the local, state and national levels are trying to block curriculums that emphasize systemic racism:
In Loudoun County, Va., a group of parents led by a former Trump appointee are pushing to recall school board members after the school district called for mandatory teacher training in “systemic oppression and implicit bias.”
And across the country, Republican-led legislatures have passed bills recently to ban or limit schools from teaching that racism is infused in American institutions. After Oklahoma’s G.O.P. governor signed his state’s version in early May, he was ousted from the centennial commission for the 1921 Race Massacre in Tulsa, which President Biden visited on Tuesday to memorialize one of the worst episodes of racial violence in U.S. history.
From school boards to the halls of Congress, Republicans are mounting an energetic campaign aiming to dictate how historical and modern racism in America are taught, meeting pushback from Democrats and educators in a politically thorny clash that has deep ramifications for how children learn about their country.
A coalition of more than six dozen scholarly and educational groups has signed onto a statement decrying the spread of proposed legislation limiting classroom discussion of race, racism and other so-called “divisive concepts,” calling such laws an infringement on “the right of faculty to teach and of students to learn” and a broader threat to civic life.
“The clear goal of these efforts is to suppress teaching and learning about the role of racism in the history of the United States,” says the statement, whose signatories include the American Historical Association, the American Association of University Professors, the American Federation of Teachers and the Association of American Colleges and Universities.
Students, read one or both of the articles in their entirety, and then tell us:
What do you think of efforts to restrict how schools teach race and racism? What do you see as the possible benefits or dangers of this legislation?
Do you agree with Republican senators that the focus on systemic racism is a form of “activist indoctrination”? Or are you persuaded by scholars who charge that laws limiting classroom discussion of race, racism and other “divisive concepts” are an infringement on “the right of faculty to teach and of students to learn” and a broader threat to civic life?
What have you studied or learned about race or racism in school, whether in the context of a history or literature class, in an advisory or homeroom, or in any other context? Looking back, how often in your school experience has race or racism been studied or discussed? Do you think the discussions you have had have been productive, informative or enlightening? Do you feel that classroom discussions on these topics have ever been avoided, silenced or marginalized?
How comfortable do you feel discussing race in school? Would you like to see the topic addressed more fully, accurately and honestly in schools? Or, do you feel that race and racism have already been explored enough — or even too much? Have you ever felt singled out, criticized or in any other way made to feel uncomfortable in a classroom because of your race or ethnicity?
A recent Tennessee House bill bans any teaching that could lead an individual to “feel discomfort, guilt, anguish or another form of psychological distress solely because of the individual’s race or sex.” A Texas House bill forbids teaching that “slavery and racism are anything other than deviations from, betrayals of, or failures to live up to, the authentic founding principles of the United States.” What impact do you think restrictions like these will have on teachers, students and classrooms? Do you think they will help or hinder a safe, healthy and productive learning environment? Will they ensure an accurate understanding of race and American history, or have the opposite effect and deny it?
What’s really going on here? How much of the debate really has to do with the tenets of critical race theory or the writing of The 1619 Project? Are public schools, according to an article by Christopher F. Rufo in The New York Post, “being devoured by a hostile ideology that seeks to divide the country by race and undermine the core principle of democratic control.” Or is legislation to restrict or prohibit critical race theory and related ideas really an attempt to “whitewash U.S. history” and “deny students and scholars the chance to understand the past,” as Kimberlé Crenshaw argues in The Washington Post? How founded are the fears on each side? Do you think there is room for common ground in the debate?
Alex Elstrodt, right, takes a moment to juggle in our Toronto office, where he’s also juggled many roles — from marketing to engineering.
By Luiz Gonzaga dos Santos Filho, Engineering Manager
“Tell me something you’re good at but others don’t know” is the kind of ice breaker question that really gets me thinking. After a brief audit of my own hidden skills, I end up more curious about the secret talents my teammates have that I don’t see every day.
Opportunities to change and grow at work help to bring these to light: I get to see colleagues in a whole new way while they get to flex in new directions inside a familiar environment. It’s a win-win. That’s why Coursera has internal mobility policies that formalize pathways to new opportunities for people within the company.
I’ve always felt that the most interesting stories have a plot twist. Let’s explore a few career pivots with these stories from Courserians.
Intern then L2 Backend Engineer then L3 and L4 Engineer to Product Manager to L4 Engineer
Zi has been at Coursera for three and a half years. He did two stints as a software engineering intern over different semesters while he was in school. After joining our team full time, he grew into a senior engineer role with a brief detour as a product manager. Zi had been interested in product management since university and was eager for an opportunity to explore the intersection of technical systems and business needs — and to flex that entrepreneur muscle.
He mentioned this to his manager and a director of product; a couple of months later, he was product managing a new project with support from two experienced PMs as well as his engineering manager.
Upon reflection, Zi thinks his technical background transferred well and helped him be a more effective product manager. On his transition back to engineering, Zi took with him more organizational, communications, and leadership skills, which gave him more confidence to drive his own technical projects as a senior engineer. He still considers one day transitioning to product or engineering management. Zi’s manager is ready to support him and, when that time comes, Zi will also be able to leverage the product manager or engineering manager apprenticeship programs at Coursera, which will set him up for success.
“I would recommend to anyone seeking alternative career paths to first look internally. It is always easier to transition internally than to apply as a newcomer to a different company with no prior experience in the role. Also, technical skills are always learnable, and people are always willing to help, so don’t get discouraged by what you currently know or don’t know.
The new experiences that will come your way as a result of trying out a new role will stay with you for a lifetime, and will help you understand yourself in new ways that will benefit your career, whether you stay in the role or not.” — Zi
Learner Services Degree Specialist to Skills Transformation Consultant
After two years as a degree specialist, Charlotte recently transitioned to a new role on the Skills Transformation team. Before Coursera, she worked in education policy and was always drawn to the power of data in shaping strategy. When she saw the new job description, she realized it would be a great opportunity to bring her broad range of experiences together to drive recommendations for our clients.
“I found tremendous support from our internal mobility team, as well as the hiring manager for the role. The resources that helped me along the way for my professional development were all in-house, from professional coaching to Coursera courses and technical mentorship with engineering colleagues. I am so appreciative of the warm welcome from the Skills Transformation team and am grateful for ongoing collaboration with colleagues and friends across the Services, Product, Design, and Engineering organizations, and look forward to continuing to foster those relationships in the new role.” — Charlotte
Intern to Teaching and Learning Specialist to Product Manager then Sr. Product Manager
Working with several product managers in her first full-time role here gave Janani great insight into the life of a PM. She saw the different styles and flavors up close — an experience that made her interested in how product managers brought together cross-functional teams to identify customer pain points and develop effective solutions. Now, Janani is four years into increasingly senior roles as a product manager.
“I had a background in neuroscience, experimental research, and education. I could see myself tapping into these aspects as a Product Manager and learn from the creativity of so many people around me.
All the PMs around me were very encouraging and created opportunities for me to build specific skills that would help me continue to explore this aspiration. The hiring manager encouraged me to apply and my own manager was very supportive. Coursera has provided several opportunities to learn, contribute and grow.” — Janani
Partnership Manager to Product Manager then Sr. Product Manager
Jenny shared the full story of her journey to product management on our blog a few years back. If you’re looking for the highlights: after studying philosophy and religion at Stanford and finishing her two-year fellowship with Teach for America, Jenny joined Coursera in 2013 as a partnership manager to help the world’s best universities grow on our platform. She became such an expert on our product that transitioning to product management was a logical next step. Over the past 4+ years, Jenny has led significant enhancements to authoring tools on our platform — even in her new role, she’s still advocating for university partners every day. Jenny is a constant reminder to aspiring product managers that one does not need a technical background to succeed as a PM.
Marketing Associate to L2 Frontend Engineer then L3 and L4 Engineer to L4 Backend Engineer
Alex has had a great, diverse career at Coursera for more than three and half years, where he’s found fertile ground to make it all possible. Check it out: he graduated with a degree in economics, started at Coursera as a marketing associate focused on SEO, transitioned to frontend engineering, made his way to senior frontend engineer, transitioned to backend engineering, and has his sights set on becoming an engineering manager in the future.
Throughout this exciting journey, Alex always had the support and mentorship of his managers and fellow engineers in his new roles, who coached him on his knowledge gaps and recommended new courses so that he could quickly learn and grow (good thing he always had access to Coursera’s lifelong learning perk to upskill!).
Here’s some advice from Courserians to kickstart your journey to a new role:
Is there a paved road? Ask the talent or learning and development teams at your company if they have an internal mobility policy. Having official apprenticeship programs to guide and support you along the way is a great way to set you up for success.
Talk to someone in the role you’re interested in. They’ll be able to provide insight into what the day-to-day looks and feels like, what skills are most important, and what you can do to prepare for the transition.
Courses can also be very helpful to fill gaps in your knowledge and upskill or reskill. Ask your company if they can support you. We’ve got just the thing for that.
Be patient and keep trying. It might take time for an internal opening in your preferred role. Keep performing in your current role while developing new skills.
Seek out or even create opportunities for yourself. Look for new challenges to take on that are related to the role you want to get. Talk to people in that role and ask them what projects or tasks you could take on on their behalf that would help them meet their objectives.
Embrace the unknown, and always keep learning. After you transition, things may not feel easy or instantly feel like a great fit. Keep learning and building your skills. One day, you’ll be looking back and find yourself mentoring someone else into a transition.
Interested in pivoting or accelerating your career alongside a new team? Check out our Careers page to explore available positions and learn why we choose to grow at Coursera.
If you’re just beginning to learn about blockchain technology, it can seem quite complicated — especially with buzzwords like decentralized, mining, token, cryptocurrency, and smart contracts. But don’t let these words and concepts intimidate you because the basics of blockchain technology are pretty straightforward.
Keep reading (or watch the video below) for our easy-to-understand explanation of blockchain, followed by an in-depth look at what blockchain is, how it works, and the ways it can be used now and in the future.
A simple explanation of blockchain
At its simplest form, a blockchain is a digital collection of information about transactions. This is also called a ledger, which is why this word is often used when describing blockchain technology.
When you have many different collections of data, they’re stored together using a system based on blocks of data chained together. Because each block is chained to those around it, they interact with each other.
This creates a system where if a block is altered, an adjacent block will immediately catch the error and prevent the invalid transaction. As a result, transactions on the blockchain cannot be changed — creating a permanent record that’s shared with everyone on the network.
The blockchain has the potential to unlock how we view and spend money, and how we’ll legitimize a variety of agreements, contracts, and technologies.
Where the blockchain came from
When most people think of the blockchain, prominent technologies like Bitcoin come to mind. Although blockchain technology isn’t dependent on Bitcoin, its development was powered by the crypto giant, and Bitcoin continues to lead the blockchain movement. But, originally, the blockchain had nothing to do with currency.
In 1991, the blockchain concept was invented as a way of verifying contents within a document using an immutable time stamp. The blockchain was designed as a way of authenticating what’s in a document and time-stamping the verification without revealing what’s inside the document. This gave blockchain transactions authenticity, immutability, and privacy.
The distributed ledger of a blockchain
A ledger is a record of transactions, and it includes important details like when the transaction was made, the parties involved, what was transacted, and any applicable amounts.
A common example of a ledger is a checkbook, which has the dates, amounts, and recipients of the checks, as well as how much you have left in your checking account. But, if you do most of your banking electronically, your monthly bank statement serves as a ledger.
On the blockchain, the ledger is distributed, which means entries are made and shared with everyone on the network. In this way, the ledger is “distributed” among many different users or peers. Every peer has a copy of the entire ledger.
How the blockchain is decentralized
Since everyone has access to the same ledger and no one person or institution controls it, the blockchain is decentralized. This makes the blockchain different from financial institutions like banks because banks have control over transactions.
Here’s an example: Let’s imagine the blockchain is like Google Docs and traditional banks are like older versions of Microsoft Word. With Google Docs, everyone who has access to the document can add to it. With Microsoft Word, on the other hand, all you can do is send a saved file for someone else to read.
On the blockchain, anyone on the network can add to the ledger while a bank merely sends out a statement. You can’t add a transaction to the bank’s ledger or perform transactions without its approval because it’s centralized.
How the blockchain is immutable
The immutable, or unchangeable, nature of the blockchain is where the Google Docs comparisons stop. Unlike Google Docs, no one can change what’s been entered into the blockchain. Each peer on the network can only add transactions. In other words, nothing that’s already been added can be altered in any way.
How the blockchain works
There are several different kinds of blockchains, like public blockchains and consortium blockchains, but they all share some key core elements. A blockchain is made up of blocks. Within these blocks is data. The data contains information that needs to be kept on the blockchain’s ledger.
For example, with cryptocurrency, the data includes:
Sender
Receiver
How much currency is being sent
Blockchains are also used in the process of tracking food. In this case, the block would contain data such as:
Where the food was harvested
The factory that processed it
Where the food was purchased
Thanks to the blockchain, if there’s a food-born disease, you can quickly figure out where the food was produced and which facilities (or even people) handled it. You can then use that information to protect others from getting infected — all within a matter of minutes or hours.
If the automobile industry were to use the blockchain, you could ensure that the odometer readings of vehicles were accurate, preventing people from tampering with them to increase or decrease value.
For example, the block could contain an accurate odometer reading and the date it was recorded. This would be stored on the blockchain, and anyone could access it to see a true record of how far the car had been driven.
Why can’t data be changed on the blockchain?
If you’re thinking to yourself, why can’t the data be changed? of course it can be — just go in a change it! You’re not alone. This is a common question and the explanation is important.
So, data stored within each block on the blockchain has what’s called a hash value. This value is generated by passing some data through a formula, and the result produced by the formula is called a hash. Usually, the hash is a string of characters, and hashes generated by a specific formula are always the same length, regardless of how much data you feed into it.
For example, the MD5 formula always produces 32 character-long hashes. It doesn’t matter if you feed just the letter C or the entire word Codecademy into the formula, you’ll always get a hash value that’s 32 characters long.
Also, the formula will always produce the exact same hash for a specific data. So, using the MD5 formula, the string for Codecademy always returns the value e2f38549c5d471e64f7c16cf44d2d36d. (Give it a try yourself.)
This is important because the hash serves as the unique digital fingerprint for each block. Along with a hash value, a checksum is also produced for a specific piece of data, and it verifies the authenticity of the data.
This helps protect against accidental changes, data-transmission errors, or hackers. Two files can be assumed to be identical only if the checksums generated for each file — using the same cryptographic hash function — are identical.
To be useful, cryptographic hash functions have to have four properties. They have to be:
Computationally efficient
Deterministic
Pre-image resistant
Collision-resistant
Here’s a bit more about each of these properties:
Computationally efficient
Computational efficiency means computers can perform the hash functions quickly. This makes it so a computer can perform the function without expending too much processing power. This enhanced power helps the overall blockchain function more efficiently.
Deterministic
The blockchain is deterministic, which means that for any given input, the hash function will always give the same result. For example, if you put in the same input a million times in a row, regardless of when you enter it, the hash function has to produce the same output every single time.
This is similar to how a regular mathematical function works. For instance, in the equation X + 2 = Y, if you make X equal to 3, Y will always be 5 or 3 + 2.
Pre-image resistant
A hash function being pre-image resistant means that its output doesn’t reveal any information about the input. So, even if you know the output, you can’t figure out the input used to create it. In this way, the pre-image-resistant nature of cryptographic hashes protects the privacy of those who transact on the blockchain.
With cryptographic hash functions, the input can be anything from numbers, letters, sentences, paragraphs, or entire books. It doesn’t matter how big or small the input is, the function itself doesn’t reveal any information about it.
Collision-resistant
When a hash is collision-resistant, it’s nearly impossible for two different inputs to produce the same output. The output of a hash is a fixed length, while the input can be any size. So, there’s a minuscule possibility of the output being the same given two different inputs.
Commonly used hash functions
Of the several different types of hash algorithms, the two most commonly used for authenticating data are MD5 and SHA-2.
MD5 (Message-Digest algorithm 5)
If you’ve heard of the MD5 hash function, you probably also know that it’s considered cryptographically broken. But, even though it has considerable vulnerabilities, it’s still commonly used as a checksum to verify data integrity. Producing a 128-bit hash value, it’s also used for a wide variety of other security applications.
SHA-2
Designed by the United States National Security Agency, SHA-2 is a family of six hash functions. One of them is the SHA-256 hash, which is used by Bitcoin. SHA-2 returns a hash value of 256-bits and is considered to be significantly more secure than MD5.
The key to the blockchain’s immutability: The hash pointer
Each block of data in the blockchain has a pointer pointing to the block before it, and each block is being pointed to by the block after it. The one exception is the first block, known as the genesis block or Block 0.
Since the genesis block is the foundation on which additional blocks are added to form a chain, it doesn’t have a previous block to point to. So, the value of the “previous hash” of a genesis block is set to 0. This simply means that there wasn’t any data processed before the genesis block.
Each block following the genesis block is numbered sequentially, starting at 1, and has a “previous hash” set to the hash of the previous block. This means each block can be traced back to the one before it and the one before that one and so on — all the way back to the genesis block.
The value of each block is determined by the hash function that runs on the data. So, if someone tries to change or manipulate the data, the hash value produced by the block will change, too. This flags the data on the blockchain as invalid, keeping the transaction secure.
For example, if you have three blocks in a blockchain, the second points to the first, and the third points to the second. If someone tries to change the data in the second block, they would also alter the hash value the block produces — because the hash function is deterministic and collision-resistant.
The pointer of the third block would no longer work because it’s looking for the original hash result. This causes the results in the blockchain to break, which then exposes the tampering attempt.
Every computer on the blockchain’s network would instantly see the invalidity of the transaction. Each computer, in effect, casts a vote regarding the validity of the data within each block. Someone would need control of more than 50% of all the computers on the network to try to validate a block that’s been tampered with.
The pointer works like a digital agreement between blocks in a blockchain, making the information in transactions such as currency exchanges, odometer readings, or where vegetables are grown immutable, or unchangeable. This level of security is one of the main appeals of blockchain technology.
The 4 qualities of the blockchain
Every blockchain has these same essential qualities:
Peer-to-peer: The blockchain isn’t controlled by any central person or authority. Everyone on the network is an equal player, and all participants talk to each other directly without the input of any third parties.
Distributed: The ledger is spread across the entire network, making it nearly impossible to tamper with. The only way to potentially alter the ledger would be to control at least 51% of the computers on the blockchain’s network.
Cryptographically secured: Cryptography is used for security purposes, and it makes the ledger tamper-proof. There’s no way to derive the data that was inputted using the output, thanks to cryptography.
Add-only: Data can only be added to the blockchain, and each entry is time-stamped, which also adds to the blockchain’s immutability.
Blockchain obstacles
While blockchain technology is, in many ways, revolutionary and extremely useful, there are a few significant obstacles.
Education
Without adequate knowledge of how to implement blockchain technology, many companies steer clear of it. Blockchain is a relatively new technology, so a lot of people don’t understand how it works or how to use it. This is slowing down the widespread adoption of the blockchain.
Even though adoption has been slow across the board, there are several companies using blockchain technology successfully today. One company taking advantage of blockchain’s transparency and data ledger technology is Spring Labs. With a mission to give businesses a way to transfer information faster and more securely, they tap into the inherent safety that comes from blockchain capabilities.
With approximately 68 million verified users, Coinbase is another company working to bring blockchain tech into our daily lives by making buying and managing cryptocurrencies easy.
Educating the public about how to use the blockchain and why it’s such an effective tool can make a big difference in the rate at which people welcome it into their day-to-day lives and business systems.
Banks and governments resist decentralization
With the blockchain, users can interact without a middleman, which removes much of the power and profit potential banks currently enjoy in the present financial system. For example, using the blockchain, you can send thousands of dollars to someone across the world in moments without paying a fee to a bank. If everyone were to adopt blockchain transactions, banks couldn’t collect wiring or transfer fees as they do now.
Governments like to have control over how people perform financial transactions, which includes knowing the identity of those receiving or sending money — or interacting in other ways, such as verifying where food was grown.
With the blockchain, the identities of the people involved in a transaction are never revealed. This makes it relatively easy for people to hide their identities when sending and receiving money and engage in a variety of contractual obligations while staying anonymous.
Usability and ease of use
Even though Bitcoin and other cryptocurrencies can be used to purchase goods and services, the lack of widespread adoption makes Bitcoin more like gold — a means of storing value.
While Bitcoin is the most popular cryptocurrency, it takes a lot longer to perform a transaction with Bitcoin than it does with a credit card. This makes some people hesitant to adopt it as a day-to-day currency.
Technology
Technological limitations also hinder the adoption of blockchain solutions. The design of some blockchains creates a bottleneck as the number of transactions grows.
The original design of the Bitcoin blockchain limited the number of transactions to seven per second. This is significantly low when compared to, say, the Visa network, which can complete thousands of transactions in the same amount of time.
The future of blockchain technology
The blockchain makes it possible for people from different parts of the world to instantly engage in business transactions and exchange, gather, and analyze data. The future of the blockchain will largely depend on people learning how it works and then adapting it to perform common tasks, as well as open up new possibilities.
Currently, some banks and financial institutions are already in the process of adopting and developing blockchain solutions because they provide fast, secure ways of sending and receiving funds.
One of the most flexible applications of the blockchain involves smart contracts. These are contracts, similar to what you’d put on paper, that allow two or more parties to agree to the conditions of a sale. When each facet of the contract has been satisfied, the transaction can go through.
For example, you could use a smart contract to facilitate the sale of a house. Everything from the home inspection to lien requirements can be included within the smart contract.
Blockchain can help with other real estate transactions, too. If someone who lives in the U.S. wants to purchase land in Jamaica but is currently visiting France, the transaction would be just as easy and inexpensive as it would if they were actually in Kingston, Jamaica. The more financial institutions adopt blockchain technology, the more common these kinds of transactions will become.
Another key factor in the future of the blockchain is the decentralized finance movement or Defi. Defi is simply finance using cryptocurrency. Defi systems make it possible for users to lend and borrow money, with those lending earning returns on the money they let others borrow.
The pros and cons of using the blockchain
As with all technologies, there are advantages and drawbacks to using the blockchain. Here are some pros and cons to consider:
Pros
An open, shared ledger system that’s tamper-proof without control of 51% of computers on the network
Decentralized management of transactions prevents large institutions or organizations from exercising central control over user’s funds
Simple, inexpensive transactions across international borders
The potential for building many types of smart contracts to facilitate a wide range of transactions and data exchanges
Cons
Currencies on the blockchain often go through dramatic swings in value
Limited adoption of blockchain solutions limits availability
Some governments are targeting financial blockchain activity, seeking to limit it
Hackers can penetrate cryptocurrency exchanges and anonymously steal funds
The future of the blockchain
In a paper about how blockchain technology can revolutionize international trade, the World Trade Organization (WTO) says that it can go far and beyond Bitcoin. The WTO predicts blockchain tech will be the beneficiary of “larger, focused investments” resulting in many successful models between 2022 and 2028. This will likely result in a “global, large-scale value-add” between 2027 and 2030.
The research also points to a spike in the business value of around 2% in 2021 to over 120% in 2030. The growth will be largely driven by the fact that the blockchain presents opportunities for:
Numerous trade-related applications
New opportunities to enhance the efficiency of processes
Paperless trade processes
A new generation of digital services produced by blockchain startups
The efficient, transparent administration of intellectual property rights
Recap: Blockchain basics
The blockchain provides users with a unique, effective, inexpensive way of exchanging currencies, maintaining accurate data, and facilitating contracts. All of this is possible because of the following elements, which differentiate the blockchain from other methods of making transactions and exchanging information:
A distributed ledger. No central organization or person controls the information. Peers on the network share the information in the ledger and everyone has an up-to-date copy.
A decentralized structure. Transactions aren’t facilitated, controlled, or altered by a central entity.
Immutable. Once the information has been entered into the blockchain, it can’t be changed.
Cryptographically secured. The transactions are secure using cryptographic functions that make it impossible to derive the input from the output.
Add-only. You can only add to the blockchain. You can’t alter previous entries.
These qualities hinge on the hash functions that form the basis of the blockchain. Hash functions are:
Computationally efficient. This means computers can solve them quickly.
Deterministic. As long as you put in the same input, you’ll get the same output.
Pre-image resistant. The output of a hash function can’t be used to determine the input used to produce it.
Collision-resistant. Two different inputs can’t produce the same output, practically speaking. The chances are less than 1 in 115, followed by 75 zeroes.
These are the basic, foundational concepts driving the blockchain, but there’s a lot more to learn. Blockchain technology is still relatively young, and, as more and more major institutions and companies — big and small — realize its potential, the market for blockchain designers is sure to grow.
With our courses, you can learn all you need to get started in a career using blockchain technology. In Learn the Basics of Blockchain with Python, you’ll gain an understanding of the fundamentals of the blockchain, as well as how to implement them using Python. If you want to take your learning to the next level, join us for free today.
