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You mentioned you might talk about how math research differs from science, but perhaps you want to think about how they are alike. This might make it easier for your audience to relate. When you get down it, pure scientific research is about describing the structure and behavior of the system in question. Ins't Isn't pure math like this? I think it doesn't occur to many people that structure is arguably the key issue in both math and science, and the practical discoveries come after structure is elucidated. So doing what seems to be "useless" pure math to a layperson is in fact essential, because the pure math describes the structure from which applications spring.

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You mentioned you might talk about how math research differs from science, but perhaps you want to think about how they are alike. This might make it easier for your audience to relate. When you get down it, pure scientific research is about describing the structure and behavior of the system in question. Ins't pure math like this? I think it doesn't occur to many people that structure is arguably the key issue in both math and science, and the practical discoveries come after structure is elucidated. So doing what seems to be "useless" pure math to a layperson is in fact essential, because the pure describes the structure from which applications spring.