Lava Lamps
• Two ingredients (water and
wax) are mutually insoluble
• Heat source tweaks the
density of one component
so when warmed, it floats to
the top
• Upon cooling, it is denser
than the other component
and sinks to the bottom
• Displays random motion
Beer
A chemical, biological, and physical process
Brewing
Batch Process
Yeast
Sugar
Bottling
Continuous Process
Ethanol + CO2
http://encarta.msn.com
Peeps
• Candy made from sugar, gelatin,
potassium sorbate, and wax
• In 1952, it took 28 hours to make one
peep – production is now 1.2 billion/yr
(enough to circle the Earth twice)
• Researchers at Emory University
have confirmed that peeps are difficult
to destroy
• Peeps have zero fat grams
• Sucrose crystallization, cross-linking
of gelatin molecules, and glassy
formation of sucrose and gelatin
during processing
Making Peeps
Squeezed onto a
conveyor belt
Dropped into boxes
Peeps get their eyes
put on
Taking a ride down
the conveyor belt
Ice Cream
• Water (milk and cream), sweetener (corn
syrup or sugar), flavorings, emulsifiers,
stabilizers, and milk fat
• Ice cream contains 20-50% air
• Ice cream has a colloidal structure – tiny
air bubbles and ice crystals are
dispersed liquid water and destabilized
fat molecules
• Ice cream has to be cooled below 0oC (~
-16oC) because of the freezing point
depression, a colligative property
• Size of the ice crystals affects quality,
and crystal size depends on freezing rate
Jell-O
• Sweetened, flavored and colored gelatin
• Gelatin: processed collagen, a structural
protein derived from pork skin, cattle
bones, and cattle hide
• Jell-O patented in 1845
• Marketed as an inexpensive dessert
during the Depression; a convenience
dessert in the 1950’s; edible
entertainment in the 1990’s
• Jell-O can be used to dye your hair, clean
the dishwasher, and deodorize cat litter
• Fresh or frozen pineapple contains an
enzyme that prevent Jell-O from setting
Plastic Bags
• Petroleum and natural gas are the
sources for the key materials in plastic
• Types of plastic depend on degree of
branching of the polymer chain:
– LLDPE = thick, glossy shopping bags from the
mall
– LDPE = garment bags from the dry cleaner
– HDPE = grocery bags
• Disposal problems
• Biodegradable bags
– Starch  lactic acid  polylactide
– Add a UV-light absorber to the polymer so that
it degrades when exposed to sunlight
Sticky Notes
• More than 1 trillion sticky notes have
been sold worldwide since 1980
• 3M adhesive discovered “by accident”
• Acrylic co-polymer of microsphere
• When sprayed on a surface, the
solvent evaporates, forming a sparse
monolayer with a pebbled surface
• This allows a limited number of touch
points, which makes the paper
removable and restickable
• Banned from libraries, archives
because of the slight residue left from
the adhesive
Contact Lenses
Materials, diffusion, fluid transport
• Regulated by FDA
• Cornea does not have blood vessels
• Cells get oxygen from air and nutrients from fluids
• Previously used PHEMA
• Now use hydrogels / silicones
(~50% water)
• How do you minimize bacteria,
fungus, etc?
Computer chips
Made primarily by Chemical
Engineers!
Integrated circuits are composed
of many layers of semiconductors,
conductors, and insulators.
1 mm
Step and Repeat Exposure Systems
hu
1/1000th of a
human hair