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.
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 Ethanol + CO2 Bottling Continuous Process
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 Peeps get their eyes put on Taking a ride down the conveyor belt Dropped into boxes
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?
1 mm Computer chips Made primarily by Chemical Engineers! Integrated circuits are composed of many layers of semiconductors, conductors, and insulators.
hu Step and Repeat Exposure Systems 1/1000th of a human hair