Chapter 2: Activity 4Movie 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

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

http://composites.poly.edu/animations/index.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!