What is AI, really?
AI, machine learning and chatbots explained without jargon.
Artificial intelligence (AI) is a big word for a simple idea: software that learns from examples instead of only following rules a programmer wrote by hand.
A normal program is a list of instructions: "if the user clicks this, do that." An AI system is different. It is shown a huge number of examples, and it learns the patterns inside them. After that, it can handle new situations it has never seen before.
Three words you will hear a lot
| Term | What it means |
|---|---|
| Artificial intelligence | The whole field: computers doing tasks that normally need human thinking. |
| Machine learning | The most common way to build AI today: learning patterns from data. |
| Large language model (LLM) | An AI trained on a very large amount of text, so it can read and write language. ChatGPT, Claude and Gemini are built on LLMs. |
How does a chatbot write an answer?
When you send a message, the model reads it and then writes its reply one small piece at a time. These pieces are called tokens; a token is usually part of a word. For each step, the model asks itself: "given everything so far, what is the most likely next piece?"
Because it learned from a huge amount of writing, those predictions can produce answers that are fluent, helpful and surprisingly smart. But it is important to remember what is happening underneath: the model is generating likely text, not looking facts up in a perfect database.
What AI chatbots are good at
- Explaining a topic in simple words, at your level
- Drafting and improving emails, posts, essays and CVs
- Summarising long text
- Brainstorming ideas, names and plans
- Helping you read, write and fix code
- Translating and changing the tone of writing
What they are not good at (yet)
- Guaranteeing that facts, numbers and quotes are correct
- Knowing about very recent events, unless the tool can search the web
- Knowing anything about you that you have not told them
- Making decisions that need real-world responsibility, like medical or legal calls
The popular chatbots
You do not need to pick a "best" one to start. ChatGPT (by OpenAI), Claude (by Anthropic) and Gemini (by Google) all have free plans and all work well for this course. Try the same question in two of them and compare; it is a great way to learn how they differ.
Try it now
Open any chatbot and paste this prompt:
Explain what a large language model is to a 12-year-old in 5 short sentences. Then give one everyday example of how I could use one.
Notice how the answer changes if you replace "a 12-year-old" with "a university student". That is your first taste of prompting, which is the next lesson.
Key takeaways
- AI is software that learns patterns from examples instead of following only hand-written rules.
- Chatbots like ChatGPT, Claude and Gemini are large language models: they predict text one piece at a time.
- They are very good at language tasks, but they can sound confident and still be wrong.