The Self-Filling Water Bottle

1 With the bike-mounted version, the rider’s speed causes air to flow through a filter, which pulls out dust and dirt. (A stationary version relies on a fan for airflow.)

2 The air then travels through a cooling chamber, and water vapor condenses on a special surface designed to draw out moisture.

3 Water trickles into the bottle at a rate of up to half a liter per hour–though it varies according to air humidity, says Kristof Retezár, the project’s designer.