sci || teach || physics || on Instagram: "Long before modern stoves or fire pits, the Dakota people used a brilliant underground system to build fire with minimal smoke and maximum heat 🔥🌍 The design used two small pits connected by a tunnel. One pit acted as the fire chamber, while the second pulled oxygen through the tunnel, feeding air directly to the base of the flame. This boosted combustion without exposing the fire. Because the flames stayed below ground, the system reduced smoke, light