How Duolingo Plans to Reach 100M Users

Class Central

Rankings
Collections

Subjects

View all

Computer Science
Health & Medicine
Mathematics
Business
Humanities
Engineering
Science
Education & Teaching
Social Sciences
Art & Design
Artificial Intelligence
Data Science
Programming
Personal Development
Information Security (InfoSec)

View all Subjects

Universities
The Report

Courses from 1000+ universities

Rankings

Best Courses

Best of All Time
Best of the Year

Most Popular Courses

Most Popular of All Time
Most Popular of the Year

Collections

Computer Science

Algorithms and Data Structures
Internet of Things
Information Technology
Computer Networking
Machine Learning
DevOps
Deep Learning
Cryptography
Quantum Computing
Human-Computer Interaction (HCI)
Distributed Systems
Blockchain Development
Operating Systems
Computer Graphics
Automata Theory
Compilers
SCADA
Mainframe
Digital Image Processing
Computational Models
View all Computer Science

Health & Medicine

Nutrition & Wellness
Disease & Disorders
Public Health
Health Care
Nursing
Anatomy
Veterinary Science
Continuing Medical Education (CME)
Blood Pressure
Wellbeing
Women's Health
Dysphagia
Occupational Therapy
Hygiene
Healthcare Innovation
Music Therapy
Holistic Health
Ayurveda
Massage Therapy
Swallowing Disorders
View all Health & Medicine

Mathematics

Statistics & Probability
Foundations of Mathematics
Calculus
Discrete Mathematics
Trigonometry
Geometry
Algebra
Precalculus
Number Theory
Combinatorics
Mathematical logic
Linear Programming
Graph Theory
Set Theory
Group Theory
Differential Equations
Polynomials
Integration
Mathematical Analysis
Mathematical Thinking
View all Mathematics

Business

Management & Leadership
Finance
Entrepreneurship
Marketing
Strategic Management
Industry Specific
Business Intelligence
Accounting
Human Resources
Project Management
Sales
Design Thinking
Business Software
Customer Service
Nonprofit Management
Innovation
Operations Management
Corporate Governance
Business Plan
Business Proposal
View all Business

Humanities

History
Literature
Language Learning
Grammar & Writing
Philosophy
Religion
ESL
Culture
Sports
Journalism
Ethics
Linguistics
Food
Library Science
Reading
Crisis Management
Games
Emergency Management
Performing Arts
Religious Studies
View all Humanities

Engineering

Electrical Engineering
Mechanical Engineering
Civil Engineering
Robotics
Nanotechnology
GIS
Textiles
Manufacturing
BIM
CAD
Chemical Engineering
Energy Systems
Aerospace Engineering
Finite Element Analysis
GD&T (Geometric Dimensioning and Tolerancing)
Geotechnical Engineering
Reliability Engineering
Petroleum Engineering
Control Theory
Environmental Engineering
View all Engineering

Science

Chemistry
Physics
Environmental Science
Astronomy
Biology
Agriculture
Materials Science
Earth Science
Applied Science
Forensic Science
Meteorology
Horology
Paleontology
Fire Science
Sensory Science
Ergonomics
Physical Sciences
Complex Systems
Scientific Method
Medicine
View all Science

Education & Teaching

K12
Higher Education
STEM
Teacher Professional Development
Course Development
Online Education
Pedagogy
Social-emotional Learning (SEL)
Instructional Design
Homeschooling
Special Education
Adult Education
Course Design
Online Learning
Educational Technology
Curriculum Development
Next Generation Science Standards
Student-Centered Learning
Student Engagement
Classroom Management
View all Education & Teaching

Social Sciences

Sociology
Economics
Psychology
Anthropology
Political Science
Law
Urban Planning
Human Rights
Sustainability
Governance
Archaeology
Social Work
Early Childhood Development
Structural Equation Modeling
Cultural Studies
Community Engagement
Philanthropy
Behavioral Science
Media Studies
Global Development
View all Social Sciences

Art & Design

Music
Digital Media
Visual Arts
Design & Creativity
Photography
Art Therapy
Art Composition
Character Design
Fashion Design
Inspiration
Golden Ratio
Pattern Design
Geometric Patterns
Copic Markers
Jewelry Design
Animal Illustration
Anime Drawing
Street Art
Observational Drawing
Greeting Cards
View all Art & Design

Artificial Intelligence

Computer Vision
Natural Language Processing (NLP)
Neural Networks
Autonomous Vehicles
Chatbot
IBM Watson
Generative AI
Intelligent Systems
Genetic Algorithms
Intelligence
Heuristics
Ontology
Collective Intelligence
Autonomous Agents
Constraint Programming
AI Ethics
Semantics
Computational Linguistics
Computational Creativity
Evolutionary Algorithms
View all Artificial Intelligence

Data Science

Bioinformatics
Big Data
Data Mining
Data Analysis
Data Visualization
Jupyter Notebooks
Process Mining
Stata
Text Mining
Social Network Analysis
Computational Analysis
Data Collection
Information Retrieval
Data Processing
Data Wrangling
Data Extraction
Data Manipulation
Network Analysis
Data Preparation
Data Analytics
View all Data Science

Programming

Mobile Development
Web Development
Databases
Game Development
Programming Languages
Software Development
Cloud Computing
Domain-Specific Languages (DSL)
Hardware Description Languages (HDL)
Aspect-oriented programming
Object-oriented programming
Visual Programming
Competitive Programming
Database Programming
Generic Programming
Programming Language Development
Leetcode
GNU Toolchain
Windsurf
Vibe Coding
View all Programming

Personal Development

Communication Skills
Career Development
Self Improvement
Presentation Skills
Resilience
Self-Control
Creativity
Gratitude
Growth Mindset
Self-Assessment
Survival Skills
Sleep Improvement
Career Planning
Empowerment
Generosity
Personal Growth
Courage
Humility
Social Skills
Dog Training
View all Personal Development

Information Security (InfoSec)

Cybersecurity
Network Security
Ethical Hacking
Digital Forensics
Reverse Engineering
Penetration Testing
Malware Analysis
DevSecOps
OSINT (Open Source Intelligence)
Threat Intelligence
Red Team
Blue Team
View all Information Security (InfoSec)

Inside the Coursera-Udemy Deal: Three Bids, Two Years and a Rival Suitor

Buried in Coursera’s 300-page prospectus: two failed merger attempts, competing bidders, a rogue shareholder, and a combined market cap that shrank from $3.8 billion to $1.7 billion.

Dhawal Shah Apr 07, 2026

Latest

8 Best Fortran Courses in 2026 (Free & Paid)
8 Best Watercolor Courses for Beginners for 2026
10 Best Terraform Courses for 2026: Automate Cloud Infrastructure
Coursera Q1 2026: Platform Fee Raises Consumer Margins to a Multi-Year High, Enterprise Customers Slip
10 Best Lua Courses to Take in 2026 (Free & Paid)

Write for The Report

Visit The Report

600 Free Google Certifications
Trending

Most common

Popular subjects

Psychology
3,086 courses
Information Technology
6,047 courses
Digital Marketing
7,313 courses

Popular courses

AP® Microeconomics
Massachusetts Institute of Technology
Let's Get Started: Building Self-Awareness
University of Maryland, College Park
Dino 101: Dinosaur Paleobiology
University of Alberta

Organize and share your learning with Class Central Lists.

View our Lists Showcase

Sign up

Log in or Sign up

Log in
Sign up

Institutions
Sarah Renae Clark

Free Online

Sarah Renae Clark Courses

21 courses

Showing 21 courses

Sort by Relevancy

Filter by

Filters

Level
1. Beginner (20)
2. Intermediate (1)
Duration
1. < 30 mins (13)
2. 30 - 60 mins (7)
3. 1 - 2 hours (1)
Subject
1. Art & Design (19)
2. Education & Teaching (1)
3. Artificial Intelligence (1)
4. Personal Development (1)
Language
1. English (21)

Turning 1000+ Pieces of Paper into Art - Paper Quilling Exploration

Explore the intricate world of paper quilling as Sarah transforms over 1000 paper pieces into a stunning artwork, featuring techniques from expert quillers and showcasing this time-consuming but rewarding craft.
- YouTube
- 22 minutes
- Self-Paced
- Free Video
Pencil Brands Are Lying to You About Being Lightfast

Uncover the truth about colored pencil lightfastness through a 6-month testing project revealing surprising results about brands' claims and actual performance.
- YouTube
- 28 minutes
- Self-Paced
- Free Video
Testing Every Colored Pencil in the World

Comprehensive review of 4000+ colored pencils from 90+ brands, testing blendability, durability, layering, and more. Includes rankings, recommendations for various needs, and alternatives to popular brands.
- YouTube
- 29 minutes
- Self-Paced
- Free Video
Can This AI Draw Anything? - Dall-E 2

Explore DALL-E 2's capabilities, limitations, and potential impact on the art industry. Artists react and discuss the AI's ability to generate diverse images, its shortcomings, and implications for creative professionals.
- YouTube
- 20 minutes
- Self-Paced
- Free Video
Pencil Sharpeners - Which Is the Best Sharpener for Colored Pencils?

Comprehensive review of 18 pencil sharpeners for colored pencils, testing ease of use, point length, waste reduction, and compatibility with various pencil types.
- YouTube
- 21 minutes
- Self-Paced
- Free Video
The Best Holbein Alternatives - Testing Pastel Colored Pencils

Comprehensive review and comparison of pastel colored pencils, exploring alternatives to Holbein and creating custom pastel sets from existing pencil collections.
- YouTube
- 20 minutes
- Self-Paced
- Free Video
Coloring Page Background Ideas and Masking Tricks

Explore innovative background techniques for coloring pages using various masking methods and mixed media. Learn practical tips to enhance your coloring projects with creative and easy-to-apply ideas.
- YouTube
- 28 minutes
- Self-Paced
- Free Video
Best Paper for Printing Coloring Pages

Comprehensive guide to selecting the best paper for printing coloring pages and colored pencil art, covering texture, weight, types, and suitability for various mediums. Includes in-depth reviews of 20+ papers tested.
- YouTube
- 31 minutes
- Self-Paced
- Free Video
Ways to Blend Colored Pencils - Solvents, Blending Pencils, Gamsol and More

Explore 12 effective colored pencil blending techniques, from burnishing to solvents, tested on different papers with wax and oil-based pencils. Discover professional tools for achieving smooth, vibrant results.
- YouTube
- 25 minutes
- Self-Paced
- Free Video
Advanced Shading Techniques for Adult Coloring Books

Master advanced shading techniques to create realistic and dramatic effects in your coloring pages. Learn about cast and form shadows, see examples in imagery, and gain practical skills for drawing shadows.
- YouTube
- 40 minutes
- Self-Paced
- Free Video
The Best Pencils for Adult Coloring, Professional Art, Drawing Skin and More - My Recommendations

Comprehensive guide to selecting colored pencils for various artistic needs, from adult coloring to professional art, with brand recommendations and performance insights.
- YouTube
- 21 minutes
- Self-Paced
- Free Video
Testing All the Best Colored Pencils for Adult Coloring - Faber-Castell, Prismacolor, and More

Comprehensive comparison of 26 colored pencil brands for adult coloring, evaluating quality, performance, and suitability for various artistic needs and skill levels.
- YouTube
- 37 minutes
- Self-Paced
- Free Video
How to Blend Colored Pencils for Beginners - Prismacolor Tutorial

Learn effective colored pencil blending techniques without solvents or tools. Master color selection, burnishing, and gradient creation for stunning results. Suitable for beginners using Prismacolor and Polychromos pencils.
- YouTube
- 23 minutes
- Self-Paced
- Free Video
The Best Prismacolor Alternatives - Affordable Colored Pencil Sets Tested

Comprehensive comparison of 7 affordable colored pencil sets against Prismacolor, testing quality and performance on various papers to find the best budget-friendly alternatives for artists and colorists.
- YouTube
- 39 minutes
- Self-Paced
- Free Video
Choosing Colors - How to Use Color Palettes for Coloring Pages

Learn to create stunning color combinations for coloring pages using color palettes. Discover how to choose, match, and apply colors effectively to enhance your artwork and boost creativity.
- YouTube
- 25 minutes
- Self-Paced
- Free Video

Browse by subject

Computer Science
Psychology
Cybersecurity
Health
Law
Accounting
Web Development

Browse by provider

Coursera
Udacity
edX
Noble Desktop
Simplilearn
CodeSignal
Boot.dev

Browse by university

Harvard
MIT
Georgia Tech
University of Michigan
Purdue University
Duke University
IIT Madras

Browse by institution

Google
Microsoft
IBM
Amazon
Linux Foundation
British Council
Salesforce

Best Online Courses of All Time
Best Online Courses of the Year
Most Popular Courses of All Time
Most Popular Courses of the Year
100 Top FREE Coursera Courses of All Time
Best Courses Guides
Free Printable Study Calendar

The Report by Class Central RSS Feed

The "New Normal" that Wasn't
DDoS Attack on Class Central
2000+ Online Degrees in India
Harvard's CS50 Free Certificate Guide
How Open University Works

Free Certificates & Courses

450+ Free Google Certificates
10000+ Free Courses from Tech Giants
300+ Free Coursera Courses
Ivy League Online Courses
200+ Free Writing Online Courses

About Class Central

Class Central aggregates courses from many providers to help you find the best courses on almost any subject, wherever they exist.

Facebook
Twitter
LinkedIn
YouTube
Bluesky

Class Central © 2011-2026 Privacy Policy

About Us
Join Us
Write for Us
Help Center
Contact Us

Share

Facebook
Twitter
Bluesky
Email

Never Stop Learning.

Get personalized course recommendations, track subjects and courses with reminders, and more.

Sign up for free

Someone learning on their laptop while sitting on the floor.