- Wahkiakum County, Washington has 262.9 square miles of land area and is the 37th largest county in Washington by total area. Wahkiakum County, Washington is bordered by Lewis County, Washington, Cowlitz County, Washington, Clatsop County, Oregon, Columbia County, Oregon, and Pacific County, Washington.
- Wave–particle duality (Wikipedia)
Wave–particle duality is the concept in quantum mechanics that quantum entities exhibit particle or wave properties according to the experimental circumstances. It expresses the inability of the classical concepts such as particle or wave to fully describe the behavior of quantum objects. During the 19th and early 20th centuries, light was found to behave as a wave, and then later discovered to have a particulate character, whereas electrons were found to act as particles, and then later discovered to have wavelike aspects. The concept of duality arose to name these contradictions.