Where does wind come from?

The Boonshoft Museum of Discovery’s education department is spending a good deal of time explaining the scientific reasons behind last week’s wind storm to visiting children. “Whenever something significant happens, it’s a great
opportunity to talk about science,” said Joe Childers, Physical Science Coordinator for the Boonshoft Museum. “They’re asking, so we’re doing our best to answer.”

The Boonshoft Museum works to apply scientific principles to nearly all subject matters, knowing the learning lessons are more meaningful when they have a direct impact on a child’s life. Because the winds affected everyone, children can readily relate to the topic. The staff is also fine-tuning an existing experiment that will demonstrate what happens when air mixes as a way to help children better understand the scientific concepts.

Mr. Childers tells children how last week’s strong winds occurred in a step-by-step explanation. The recent windstorm had four components: a cold front passing overhead, a region of high atmospheric pressure to the east, strong winds about a mile up in the sky, and the remnants of Hurricane Ike. When Ike’s low pressure combined with the cold front, there was a large difference in pressure.

Typically, when a cold front passes through, it pushes the air ahead of it high in the atmosphere, where it cools and clouds form. Because Ike’s air was so warm, clouds did not form, which let the Sun warm the ground without interruption. The air along the ground heated up and began to rise, displacing the air above it, forcing the higher
air to come down to the ground. This brought some of the winds a mile up in the sky down to add to the winds from the pressure. This rare combination of factors led to the unusually high winds, and much of the resulting damage.

Mr. Childers has also begun modifying an experiment to help visually demonstrate what happened with last week’s high winds. “Our goal is to provide hands-on learning for our visitors. While we can’t recreate the winds in our Science Theatre, we are working on an experiment with water to show how warm and cool, high and low mix to create “convection currents,” which is exactly what happened with the winds throughout Ohio last week.”

To conduct the experiment at home, rest an empty, clear container (an aquarium is preferred, or something of similar size) on two identical sturdy buckets or bowls. Fill one supporting bucket to the brim with extremely hot water, the other to the brim with extremely cold water, and the clear container with room temperature water. (The hotter and colder the water can be, the better!) Naturally one side of the clear container water will begin to cool while the other heats, setting up a temperature difference between the two adjacent fluids. These are the ingredients for “convection.”

After a few minutes, the difference in temperatures will begin to develop, which is the time to squirt a liberal amount of two varying-colored food dyes into each side of the clear container. The dye should begin to follow a circular path around the clear container. Water above the hot side rises and water above the cold side falls, creating a circular current, or a convection cell.

Because air behaves the same as water (they are both fluids), it becomes less dense as it is heated up, making it want to float on top of air at a lower temperature. While this experiment with water will demonstrate convection currents in a horizontal motion, the winds of last week were producing vertical motion. There, the heating agent was the warm air on the ground and the cooling agent was the cool air above.

As the warm air rose and cooled, the rising air pushed the cool air out of the way and forced it down to the ground in a circular current of air, bringing the strong winds with it.

The Boonshoft Museum of Discovery, 2600 DeWeese Parkway, Dayton, is open for exploration Monday-Friday 9am-5pm, Saturday 11am-5pm and Sunday 12pm-5pm. Admission is $8.50 adults; $7.00 seniors; $7.00 Child 2 – 12; children under 2 and members are free. (937) 275-7431 www.BoonshoftMuseum.org