To expand means to grow larger. In science, most materials expand when they are heated and contract (grow smaller) when they are cooled.
At the end of April 2009, the Explorers investigated the properties of density, using what was surely one of the strangest contraptions to ever appear in (and above) their schoolyard.
As everyone knows, a hot air balloon rises because of...well, hot air. No helium or other "trick" is used, just the properties of air itself. How does this work? It all has to do with density.
OH - Dayton / Wright-Patterson Air Force Base
- Broken clouds
- Temperature: 66.2 °F / 19 °C
- Wind: Northeast, 3.5 mph
- Pressure: 1012 hPa
- Rel. Humidity: 88 %
- Visibility: 16.1 km
Sun, 08/01/2010 - 03:58