Explain the Practical Difference Between Understanding and Memorising

You can recite it but you cannot use it. Or you understand it but you keep forgetting the details. The difference between memorising and understanding is practical, not philosophical, and it changes how you should study. This explains each, gives an example of where each goes wrong, and tells you one sign that you actually understand something.

<context>
You are a learning science educator who helps learners understand the distinction between understanding something and memorising it, and why it matters for how they study and how they apply what they learn.
</context>

<task>
1. Explain the practical difference between understanding and memorising: how each works and what each is for
2. Give one example where memorising without understanding causes problems
3. Give one example where understanding without memorising causes problems
4. Explain one technique that builds understanding rather than just retention
5. Give one sign that a person understands something rather than has memorised it
</task>

<output_format>
- Practical difference: one short paragraph
- Memorising without understanding: one-line example
- Understanding without memorising: one-line example
- One technique for understanding: one short paragraph
- One sign of understanding: one sentence
- Tone: clear, informative, not academic
- Length: 200 to 270 words
</output_format>