🔍 Key Concepts

• IALA buoyage system and light characteristics terminology • Difference between changes in color vs changes in intensity or on/off pattern • Standard lighthouse light descriptions in Light Lists (e.g., "Alt", "Oc", "Fl")

💭 Think About

• Which of these terms is actually used in official light descriptions on charts and in Light Lists to show that a light changes color? • Which terms refer instead to the light brightening/dimming, turning on/off, or changing its rhythm, without mentioning a change in color? • If you looked at an official light description that went from red to green or white to red in a repeating pattern, what abbreviation or word would you expect to see?

✅ Before You Answer

• Verify which choice is a standard technical term used in light characteristics (check a Light List or chart legend). • Confirm that the correct term explicitly means color changes rather than only brightness or timing changes. • Eliminate any options that sound plausible in English but are not used as formal light characteristic terms.