MSU logo Minority Serving Institution Partnership Development Program

Remote Sensing: Fun Facts

Check out a few buoyancy and imaging applications that relate to everyday life.

  • Icebergs
  • Water Bottle pressure
  • Aerodynamic Vortex
  • Water Droplet Images

Iceberg

Ice floats! Water is different than most substances in that its solid form is LESS DENSE that its liquid form. As we learned on the blimp page, if ice is less dense that liquid water, it weighs less than the water it displaces, giving it a net upward buoyant force, and causing it to float up to an equilibrium with part of it sticking out of the water. So all ice floats in water.

Dead Sea FloatingIcebergs in the ocean have a few more characteristics that contribute to their buoyancy. For one, ice bergs are not pure ice - they have a lot of air pockets. The light-weight air takes up space but weighs very little, increasing the buoyant force on the iceberg. Another factor is that ocean water is not pure water - it has a lot of salt in it. The salt particles are more dense than water, so the density of salt water is higher than pure water, again increasing the buoyant force on the iceberg. Have you noticed that it is easier to float in the ocean than in a swimming pool? The Dead Sea has a very high salt content, so most people can float with little to no effort in it.

Pressurized Water BottleThe buoyancy of your blimp depends on the interplay of the helium pressure inside and the atmospheric pressure outside. Atmospheric pressure slowly diminishes with altitude because there is less atmosphere above the location to weigh down on the air.

This water bottle shows the change in air pressure (and therefore density of air) from different altitudes. The water bottle was capped at an altitutde of almost 7,000 feet where the atmospheric pressure is low (causing a lower density of air) and brought down to Death Valley, which is slightly below sea level where the atmospheric pressure is high (causing a greater density if air). The air pressure from the high density air around the bottle overpowers the air pressure from the low-density air inside. This causes the bottle to collapse under the pressure of the air outside.

Airplane vortex

 

The aerodynamics of an airplane cause air above the wings to be at a lower pressure than air below the wings. The air at the higher pressure tries to circulate around the edge of the wing to the lower pressure area, creating a vortex. Red smoke around this airplane makes the vortex show up.

Refraction from Waver Molecules

 

Each water droplet on this plant stem creates a whole image of the background flower. Water droplets have curved surfaces that act like a lens and refract light from a background flower. The light is focused into a small image.