Quick Answer
Often, yes—through AI detectors, style analysis, and knowing your previous work.
Detailed Answer
Teachers detect AI writing through: AI detection tools (imperfect but improving), dramatic style changes from your usual work, generic or overly polished writing, factual errors typical of AI, and metadata/timestamps. AI detection isn't foolproof, but getting caught has serious consequences. Better approach: use AI to learn and improve YOUR writing, not replace it.
Find Your Own Answer
The best way to decide is to try them yourself. Council lets you compare multiple AI responses to the same question.