The Denver Post |
The science behind the color-changing solar eclipse US postage stamps? Fat magic
The Denver Post The Total Eclipse of the Sun Forever stamp debuted June 20, 2017. It's the U.S. Postal Service's first heat-activated stamp. Using thermochromic ink from Chromatic Technologies Inc. in Colorado Springs, the stamp's black ink spot vanishes when you … Solar eclipse 2017: How to get eclipse stamp that changes when you touch it Total eclipse watch party: 5 must-have eclipse party favors Great American Eclipse: locals hope to catch full experience, students plan to document |
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