Metales

duccion
Por experiencia todos sabemos que si dejamos caer un tornillo de metal en un balde de agua el mismo llegara hasta el fondo sin parar. Sin embargo, si ponemos un barco sobre el agua, con todo y su peso no se hunde. Cuál es la razón de este fenómeno?
Lo que determina que un objeto se hunda o no es la densidad. (que es igual a masa por unidad de volumen). Si el objeto es más denso que elfluido, se hundirá. Si el objeto es menos denso, flotara. Si es de la misma densidad, ni se hunde ni flota. En el caso de los barcos, es la forma del casco del barco lo que importa. El caso guarda aire, volumen de aire, asi que su densidad total es menor que la del agua.
Archimedes descubrió que si un objeto es sumergido en el agua desplaza un volumen de agua igual al volumen del objeto. El aguadesplazada crea una fuerza de igual intensidad hacia arriba. Si el peso del agua es mayor que el del objeto, este flotara.
Este proyecto tiene como proposito comprobar esa con varios material de distintas formas.
 
Hipotesis
El propósito de este proyecto es determinar a cuanto peso puede someterse un pedazo de metal sobre el agua. Tomando el principio que se utiliza para la construcción debarcos, utilizaremos materiales similares, aunque no de igual tamaño para probar como se desplaza el agua debajo de estos objetos.
 

Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to understand the following terms and concepts:
• weight,
• volume,
• density,
• buoyancy,
• displacement.
Bibliography
• Here aresome good background resources on buoyancy:
o Junior Engineering, 1997. "Buoyancy," Utah State University [accessed December 29, 2006] http://www.engineering.usu.edu/jrestate/workshops/buoyancy/buoyancy.php.
o Wikipedia contributors, 2006. "Buoyancy," Wikipedia, The Free Encyclopedia [accessed December 29, 2006] http://en.wikipedia.org/w/index.php?title=Buoyancy&oldid=97455729.
• Here's anarticle to get you thinking about what happens if the fluid in which the object is immersed has a density lower or higher than that of water:
Phillips, T., 2005. "Rainbows on Titan," Science@NASA [accessed December 29, 2006] http://science.nasa.gov/headlines/y2005/25feb_titan2.htm.
• The following link shows you how to make a Cartesian Diver, which will make an interesting demonstration ofbuoyancy you can use along with your display board (requires Adobe Acrobat Reader):
Terrific Science Press, 2005. "Cartesian Divers," Terrific Science Press [accessed December 29, 2006] http://www.terrificscience.org/ncw/2005/pdf/Cartesian%20Divers.pdf.
Materials and Equipment
For building the boats you can use:
• cellophane tape (e.g. "Scotch" tape), and
• aluminum foil.
For measuring thevolume of the boats, you will need either:
• a ruler (for measuring the dimensions of the boat in order to calculate its volume), or
• dry rice kernels and
• a glass measuring cup with metric markings (or a graduated cylinder).
For testing the buoyancy of the boats you will need:
• a container (e.g., sink, tub, bucket, dishpan) with water,
• pennies.
Experimental Procedure
1. Use thefoil and tape to construct boat hulls with different shapes.
a. You can fold or even cut the aluminum foil if you wish to obtain the desired shape.
b. It is important to insure that there are no leaks!
c. Try building several different boats using the same amount of aluminum foil for each.
d. Also try building several different boats using different amounts of aluminum foil.
2. Calculatethe volume of each boat hull. Below are two alternative methods you could use. (Or, you could use both methods, and compare your results. Which method is more accurate?)
a. Ruler Method
 Use the ruler to measure the length, width, and height of your boat hull.
 Volume (in cm3 equals length × width × height (each measured in cm).
 If parts of the hull have an irregular shape, measure...