Uploaded August 2019 | Updated September 2026, 3 weeks ago
Can water escape from a glass using only paper towels? Find out in this video!
Equipment: glasses, water tinted with food coloring, paper towels.
Arrange several glasses, alternately full of tinted water and empty, and connect them with paper napkin bridges. Over time, the water will flow from the full glasses to the empty glasses until the water level is equal across all the glasses.
A paper towel consists of plant fibers with numerous capillaries in their structure. When water enters them, its surface adopts a concave shape, forming a meniscus. Meanwhile, the water pressure under this meniscus becomes lower than atmospheric pressure, and the water begins to rise. The thinner the capillary, the higher the water can climb. The process will stop when the water levels in the glasses equalize, bringing the system to a state of balance. The main factor in the process is the height difference between the surface of the liquid and the bend in the paper towel, so the forces pushing the water into the new glass equalize with the forces trying to push the water back.
Safety precautions: none.
Can water escape from a glass using only paper towels? Find out in this video!
Equipment: glasses, water tinted with food coloring, paper towels.
Arrange several glasses, alternately full of tinted water and empty, and connect them with paper napkin bridges. Over time, the water will flow from the full glasses to the empty glasses until the water level is equal across all the glasses.
A paper towel consists of plant fibers with numerous capillaries in their structure. When water enters them, its surface adopts a concave shape, forming a meniscus. Meanwhile, the water pressure under this meniscus becomes lower than atmospheric pressure, and the water begins to rise. The thinner the capillary, the higher the water can climb. The process will stop when the water levels in the glasses equalize, bringing the system to a state of balance. The main factor in the process is the height difference between the surface of the liquid and the bend in the paper towel, so the forces pushing the water into the new glass equalize with the forces trying to push the water back.
Safety precautions: none.
