This awesome model Earth is simple and fun to make. It takes about 3 hours to build. Materials include a styrofoam ball, poster paint, invisible paint and a uv torch to illuminate it. The model earth will show the internal structure including inner core, outer core and mantle. The hidden tectonic plates are made visible with the uv torch.
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https://www.youtube.com/watch?v=Yv21qqioDtA