Coriolus Effect (Denise Randol)

Author

Denise Randol

Principle(s) Illustrated

1. Centripetal Force: Centripetal Force: pulls object toward center. Inertia is always moving an object tangentially or at a right angle from the line to the center (radius). M x V squared divided by the radius.

2. Newton's Law an object remains in a state of rest or uniform motion unless it is acted upon by an external unbalance force---objects in motion tend to stay in motion unless an outside force acts on it and stops it.

Standards

6th grade

MS-ESS2-6. Develop and use a model to describe how unequal heating and rotation of the Earth cause patterns of atmospheric and oceanic circulation that determine regional climates. [Clarification Statement: Emphasis is on how patterns vary by latitude, altitude, and geographic land distribution. Emphasis of atmospheric circulation is on the sunlight-driven latitudinal banding, the Coriolis effect, and resulting prevailing winds; emphasis of ocean circulation is on the transfer of heat by the global ocean convection cycle, which is constrained by the Coriolis effect and the outlines of continents. Examples of models can be diagrams, maps and globes, or digital representations.] [Assessment Boundary: Assessment does not include the dynamics of the Coriolis effect.]

8th grade

MS-PS2-2. Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object. Emphasis is on balanced (Newton’s First Law) and unbalanced forces in a system, qualitative comparisons of forces, mass and changes in motion (Newton’s Second Law), frame of reference, and specification of units.] [Assessment Boundary: Assessment is limited to forces and changes in motion in one-dimension in an inertial reference frame and to change in one variable at a time. Assessment does not include the use of trigonometry.]

Questioning Script

Prior knowledge & experience:

• Students know that food coloring will spread out in water and change its color

• Students know on a merry go round or other spinning device, they lean out as they spin around curve.

• Students may have observed ice skaters spinning and pulling their arms into their bodies to spin faster. They continue to spin until the skater changes their foot position.

Root question:

1. What will a drop of food coloring do in a spinning container of water?

2. How does the action of the food coloring model the action of material in the Earth's liquid outer core?

3. What is the Coriolis Effect?

Target response:

1. The food coloring will spin with water in a mini vortex, centripetal force will pull the color inward, until another force disrupts it. As long as the container is spinning, the water will stay in motion and the drop of food coloring will continue to spin as well. The only reason the colored spirals begin to spread is the inconsistent speed of the turntable disrupts the velocity.

2. Magma continually spins around the metallic inner core, generating an electromagnetic field. It is this field that creates a protective force around the Earth.

3. The Coriolis effect is a when a mass (food coloring) moving in a rotating system (the water) experiences a force (the Coriolis force ) acting perpendicular to the direction of motion (pulling into the center at right angle) and to the axis of rotation. On the earth, the effect tends to deflect moving objects to the right in the northern hemisphere and to the left in the southern and is important in the formation of cyclonic weather systems.

Common Misconceptions:

Students believe that when you spin water with food coloring it will mix with the water faster.

Food coloring is just like water, except a different color.

Photographs and Movies

Put all photos in the class Picasa Album and reference here. Do not upload the photos directly to this wiki as there is not enough memory in the website.

Put all movies in your own Youtube account. Make sure that the account is set for public viewing. Insert the Youtube videos here.

References

Newton's First Law Youtube video example of students using everyday objects in inventive ways.