Soon after this incident Dr. Denis Osborne, a physics professor, visited Mpemba’s school. He did not have an answer when Mpemba asked why hot water freezes faster than cold water. However, he was so intrigued by the question that he began to work with Mpemba to solve the conundrum. This was more than 40 years ago.
Since then, many scientists have searched for an explanation, but have failed to reach a consensus. One theory is based on the process of evaporation. Hot water will evaporate more quickly than cold water, with a greater change in volume in a given time. Evaporation causes heat loss, and lower mass also makes it easier to reduce the temperature of water and to get the water to freeze. Thus, some scientists theorized that rate of evaporation may be at the root of the Mpemba Effect.
- This theory was one of the first propose
- This theory was one of the first proposed
- There had to be other causes for the effect, they both concluded.
- Еhat he began to work with Mpemba to solve the conundrum
This theory was one of the first proposed, but it became one of the first in a long chain of theories to be tested since 1970. During initial experiments conducted, Mpemba, working with Dr. Osborne, compared various heated beakers of water to those that were not heated. They found that evaporation causes only slight changes in volume. No more than 30 percent of the cooling could be attributed to this volume loss. There had to be other causes for the effect, they both concluded.
Still, the Mpemba Effect remains a very real phenomenon with impacts outside of the lab. Besides Mpemba’s ice cream observation, this effect can be seen in other aspects of daily life. The recent fad of making “instant snow” on chilly days by throwing boiling water up into the air is a manifestation of the Mpemba Effect. Room temperature water thrown up into cold air results in nothing more than the water falling to the ground. Despite such interesting observations, the Mpemba Effect remains an unsolved mystery.
