Review+2+density

Name: Date: 8th Grade Science – STEM Middle Academy – Mr. Condon Block: Review #2 for test Tuesday Imagine a day at the beach. Solar radiation (sunlight) passes through the atmosphere and strikes the sand and the water. The light turns to heat (infrared radiation) when it strikes any object – think about a car left outside on a hot summer day. Since sand is light colored it **reflects / absorbs** (choose one) the heat created. The opposite occurs in the water. The air above the sand becomes hotter than the air above the water which is absorbing all the energy from the sun since it is relatively dark. Adding heat to an object causes the object to increase in volume. Since its mass remains the same, its density must **increase / decrease** (choose one). We therefore say that volume and density are inversely proportional – when one goes up, the other goes down. If the air over the beach becomes less dense than the air higher up, it will surely **rise / fall** (choose one), just like a hot air balloon. The air over the water is actually cooling as its energy is absorbed by the water. As this cooler air becomes more dense, it sinks toward the water. Nature hates a vacuum and so air will always flow from areas where it is more dense to areas with less density. We call this flow wind. During the day, winds along the shoreline flow from the ocean and onto the beach. These are called **on-shore breezes**. At night, **off-shore breezes** occur as the process above is reversed. In the space below, draw a diagram depicting the on-shore breezes at the shoreline. Be sure to indicate the direction of wind flow and the relative density of the air above the sand and water.

On the reverse of this page diagram off-shore breezes as you did above for the on-shore winds.