National Chemistry Week (October 17-23) is just around the corner and howtosmile.org is ready! We’ve got some great activities to support this year’s theme: "Behind the Scenes with Chemistry,” which focuses on the chemistry behind movie special effects. All of the links below are also on a SMILE list.
Light, color, action!
First, there's the original movie special effect -- the fact that still images can trick our brains into seeing motion.
Learners can Make a Flipbook of a dancing stick figure by dragging dance move snippits to a timeline, then print out the results and assemble them into a physical flipbook. This effect is usually called "persistence of vision," but there are interesting articles questioning this historic term, drawing on research into how our eyes and brains actually perceive moving images. Another activity option for demonstrating this effect is the Thaumatrope Illusion. Using index cards spun on a drinking straw, learners can make two separate drawings appear to become one. Or if you don't have a straw, rubber bands can be used, as described in the Motion Picture activity (which is also in Spanish, "Imágenes en acción").
There's the effect of Color Mixing, where red, green, and blue light can be added together to create the millions of the colors that appear on a screen. If you've heard of "rods and cones" in your eye, color is received by the "cones." (The "rods" work better in the dark, but they're single-color.)
And of course there's the photochemical reaction that actually allows images to be recorded on film. This can be simulated with Sun Prints. Like photographic film, Sun Prints are coated with chemicals that are sensitive to light, and when exposed to light the chemicals react where the light strikes, forming an image.
Fake scars, fake snow, and real explosions
Having covered some activities about the movies themselves, here are some ways of exploring the effects we see in the movies.
First there's the magic of movie makeup! A pretty effective Scar Face effect can be made using milk, gelatin, and water. I'm not sure what the chemistry is, but I think it's a reaction between the casein protein in milk, and gelatin, which is itself a natural polymer. A model for polymers comes from the Polymers are chains (K-2) activity. It uses paper-doll-strings to represent monomers (the role I think gelatin plays), and tape donuts to represent a binding agent (probably the casein). The polymer model activity is followed by an activity to make flubber, another type of polymer that starred in a movie with Robin Williams -- Flubber!
For controlling the weather on a movie set, any day can be a Snow Day! with fake snow. This fake snow can be made using the chemical (sodium polyacrylate) that's found in baby diapers for absorbing liquids. When mixed with water, this chemical looks like snow -- only it's not cold! Closer inspection shows that it doesn't have the very cool crystal structures seen in movies with real snowflakes. If it snows this winter you can go on a Hexagon Hunt for them.
Pyrotechnics -- flames and explosions -- are an important part of movie magic. The activity Fireworks shows how different colored flames can be created by burning different chemicals. The activity is a traditional chemistry flame test, and can be supplemented by a background site from NOVA on fireworks. For explosions, the Pop Rockets activity ("Cohetes que saltan") gives a taste of how reactions in confined spaces can cause bigger effects.
NCW Before ICY
There are lots more ideas and resources on the NCW page, More resources NCW 2010 Book and Video Resources List and the Electronic Resources List.
We're going to continue with chemistry after National Chemistry Week -- howtosmile.org is getting ready for the International Year of Chemistry 2011! Read more about our new collection of chemistry activities, and the other resources we're working on to help support an informal chemistry community, from how to work safely with chemicals to where to dispose of them.