Chapter 2: Activity 4 Movie Special Effects

Materials in Science There are 4 basic types: 1. Polymers (gak & oobleck) 2. Composites (paper mache) 3. Metals (aluminum& titanium) 4. Ceramics (clay or carbides)

Lets Discuss Composites Composite: are heterogeneous materials consisting of two or more separate materials combined in a macroscopic structural unit. ex: papier-maché

Composite Decking: plastic (either polyethylene which is malleable or polypropylene which is rigid) and wood fiber Examples of Composites

Concrete Driveways/Roads: Reinforced Concrete steel rods & concrete Examples of Composites

Airplane Composite Material: Do you see the many thin fibers?

Examples of Composites Human bones

Examples of Composites Anatomy of a Baseball

Baseball dissection The official National League Baseball.

Baseball Dissection The dissection begins...

Baseball Dissection The leather cover is peeled back to reveal a layer of twine

Baseball Dissection This first layer of thin twine is peeled away. This thin layer creates a smoother surface on which to place the leather cover.

Baseball Dissection With most of the first layer of twine gone, the darker, heavier yarn underneath is revealed. Many cheaper baseballs have only a solid mass of cork/rubber amalgam under the first layer of yarn, but with a pro ball, the yarn has only just begun!

Baseball Dissection Unraveling the dark wool yarn begins. The bits of red thread you see are the anchor points for the heavy red stitching used on the baseball's leather cover.

Baseball Dissection The dark yarn gives way to a layer of white yarn. Winding these layers of yarn tighter or looser can affect the elasticity of the baseball. A tighter wrap results in a livelier ball.

Baseball Dissection Back to dark yarn again. A cat would love this process -- countless yards of yarn!

Baseball Dissection The baseball shrinks as the pile of dark yarn grows. This last layer of dark yarn makes up most of the baseball's size and mass.

Baseball Dissection We're down to a thin layer of red rubber, and the ball is about the size of a Superball. Drop this ball, and you'll discover that it is quite bouncy! The outer layers of yarn clearly serve to moderate the elasticity of the rubber ball.

Baseball Dissection One last cut, and the tiny cork core is revealed. Notice that the red rubber layer gives way to a layer of black rubber as well. The cork core is about the size of a small grape.

Pykrete A composite of ordinary saw dust and water frozen together.

History of Pykrete

How they are made html html

Why Use Composites Titanium-light and strong (good) but extremely expensive (bad) Aluminum foil is light (good) but extremely malleable (bad) Put them together to make a composite

Why Use Composites So, if we put the two metals together in the right combination, we can keep the cost down and still make a strong material. Aluminum sheets Titanium to reinforce

Use of Composites Today Boats (hulls) & Cars (body) Sport equipment (rackets, skis…) Artificial limbs Aircraft & Aerospace structures

Advantages of Composites Low weight High stiffness High strength Low radar signature (stealth) Extend the life of material Can be customized for a specific application

Disadvantages of Composites High initial cost of research Manufacturing time Use of special raw materials

The Future Composite materials have great potential in the decades to come. It is an exciting field and a great career choice! You might be the next billionaire!