Collier and Marvin Lilley -- The Hydrothermal Vent Prospecting Team
Activity: Current Patterns
Students can study the air currents within their classroom to examine
how wind and ocean currents distribute particles through different
Matches or incense.
- Have the students sit at their desks and close their eyes.
- Instruct the students to raise their hand when they can smell
- Light the match or incense and blow it out.
- Draw a diagram to "map" the pattern in which students
raised their hands. For example, did all of the people in the
front smell smoke first, and did any of the students near the
window smell the smoke at all? Based on the diagram, have the
students (i) try to determine where you were standing when you
created the smoke; and (ii) interpret the air currents in their
- What might be the sources of air movement in the classroom?
Are there any other factors that might affect how well a student
detects the smoke?
- Repeat the experiment, but change some of the parameters. Have
the students raise their hand when they smell smoke, but position
yourself in a different part of the room, turn on a fan, open
a window, have a couple of students pace back and forth, etc.
- How do these changes affect the overall patterns?
Wind and ocean currents move in much the same way, and distribute
smells and particles sometimes over long distances. Currents
can be fast or slow, and can change daily and seasonally.
Certain winds are always present and drive the world's weather
patterns. Winds also drive surface currents in the ocean. The Trade
Winds drive surface currents in subtropical regions to the east,
while the Westerlies drive surface currents at higher latitudes
to the west.
In the deep ocean, currents are driven by density differences,
which are caused by variations in the salinity and temperature
of deep ocean water. Both surface and bottom currents are also
affected by Coriolis force (due to the Earth rotating), tides,
the topography of the seafloor, and the distribution of land.
Scientists on board RV Knorr tow CTD sensors that measure conductivity,
temperature, and depth) near the bottom of the ocean to help locate
hydrothermal vent plumes. Much like students raising their hands
when they first smell smoke, the CTD sensors help "sniff" for
telltale signs, such as changes in temperature, salinity or water
clarity, of hydrothermal vent plumes.