Create a current
Winds constantly move water across the surface of the ocean, creating currents. Find out how wind affects ocean motion by creating your own!
What you need:
- An aluminum pie plate or glass baking pan
- Water
- Food coloring
- A straw
- A small bowl or other small waterproof object
- Aluminum foil
What to do:
- Fill the pie plate or pan with water (leaving a little space at the top).
- Place a drop of food coloring at one end of the pie plate.
- At the other end, blow through the straw to create “wind” across the surface of the water. How does the water move? What happens to the food coloring?
- Now place the bowl upside-down in the pie plate to represent an island or continent.
- Place a drop of food coloring in front of the bowl and blow through the straw across the water’s surface. What happens to the food coloring now?
- Next, create a small “boat” out of aluminum foil and place it in the water. Create wind by blowing through the straw again, and try to direct the path of the boat. Does the boat move in the direction you want it to?
Using currents in real life:
- Every year, teams of sailors leave shore and race around the world on sailboats. Learn more about the Volvo Ocean Race.
- Just how far can a message in a bottle travel on a current? Play a board game and read a story to find out.
Activity based on Wind-Driven Ocean Currents from NASA.
5 three ounce paper Dixie Cups
2 soda straws
pin
paper punch
scissors
stapler
sharp pencil with an eraser
PROCESS:
Take four of the Dixie Cups and use the paper punch to punch one hole in each, about a half inch below the rim.
Take the fifth cup and punch four equally spaced holes about a quarter inch below the rim. Then punch a hole in the center of the bottom of the cup.
Take one of the four cups and push a soda straw through the hole. Fold the end of the straw and staple it to the side of the cup across from the hole. Repeat this procedure for another one-hole cup and the second straw.
Slide one cup and straw assembly through two opposite holes in the cup with four holes. Push another one-hole cup onto the end of the straw just pushed through the four-hole cup.
Bend the straw and staple it to the one-hole cup, making certain that the cup faces the opposite direction from the first cup. Repeat this procedure using the other cup and straw assembly and the remaining one-hole cup.
Align the four cups so that their open ends face in the same direction either clockwise or counter-clockwise around the center cup.
Push the straight pin through the two straws where they intersect.
Push the eraser end of the pencil through the bottom hole in the center cup. Push the pin into the end of the pencil eraser as far as it will go.
Now your anemometer is ready for use!
EXPLANATION:
An anemometer is useful because it rotates with the wind. To calculate the velocity at which your anemometer spins, determine the number of revolutions per minute (RPM). Next, calculate the circumference (in feet) of the circle made by the rotating paper cups. Multiply your RPM value by the circumference of the circle and you will have an approximation of the velocity of at which your anemometer spins (in feet per minute). Your anemometer doesn’t need to be pointed in the wind for use.
Note: Some forces are being ignored including drag and friction for this elementary illustration, so the velocity at which your anemometer spins is not the same as wind speed.