medieval spectacle makers lenses microscope telescope

Medieval lens makers improved spectacles by observing

Medieval spectacle makers improved lenses by observing what worked, even though the optical ideas of their time could not fully explain how spectacles worked. Their practical lensmaking tradition helped enable the compound microscope and refracting telescope.

A gas eruption can build a tsunami

In a limnic eruption, a trigger lifts carbon-dioxide-rich deep water into lower pressure. Gas bubbles form and lift more water, bringing still more gas upward. The growing gas column can displace enough water to produce a tsunami.

None of Nunavut's 25 communities are connected to each other by road

Nunavut covers an enormous part of northern Canada, but none of its 25 communities has a road connection to another Nunavut community or to the main North American road network.

Like this? There’s a whole feed of it. Replace empty scrolling with things worth knowing.

Download Hence for free

medieval spectacle makers lenses microscope telescope

Medieval lens makers improved spectacles by observing

Keep exploring