Sciencespeaking topic
SPF doesn't work in a straight line: SPF 30 blocks about 97 percent of the rays and SPF 50 about 98 percent, only one point apart. So why do we buy 50, and is high SPF a marketing illusion?
— SPF logarithmic protection curve / dermatology
practice with this topic
Set the timer (5-30 min), take 20 seconds of prep if you like, start talking. Jot your thoughts onto the sticky-note board.
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