E2-13
Show how sunspots are darker than their surroundings due to lower temperatures.

Three light bulbs are mounted along a rod: two 150 watt bulbs with a 15 watt bulb between them. The lower-power center bulb appears darker, compared to the two brighter bulbs, because it has a lower temperature.

Sunspots appear darker than the surrounding area because they are regions of lower temperature.
E2