Task


Complete 3.02 Combustion Questions using the On Fire virtual lab from PBS. Submit your completed work to the 3.02 Combustion Questions Dropbox.

Step 1: Background Essay

First, read the Background Essay for this virtual lab below:

The anatomy of a candle flame is complex, and both physical and chemical reactions are involved in producing it. In a room with still air, a flame hardly flickers. It burns at a fixed distance above a pool of melted wax. Everything is in balance, as wax is consumed, light emitted, and heat produced. Enclosed within the flame's bright yellow tongue is a dark cone that rises from below the curl of the wick. At the bottom of the flame—around the wick but not quite touching it—is a blue region of lesser brightness that seems to envelop the base of the dark and yellow regions above it.

As a flame burns, heat radiates equally in all directions and melts the candle's solid wax into a hot liquid pool of usable fuel. Where the melted wax meets the heat of the flame, it evaporates, forming a gas. This vaporized fuel floats up from the wick and out to the edges of the dark zone. Here, wax vapor meets oxygen molecules from the air. This is the main reaction zone, where combustion takes place. Measuring about 1,400 degrees Celsius, this glowing blue region is the hottest part of a flame. The products of this combustion flow up into the yellow tongue of the flame, which is made up of carbon particles heated to incandescence.

Fuel molecules that don't burn up right away—because not enough oxygen is present—combine to form particles called soot, which swirl around inside the body of the flame without actually burning. Eventually, though, most of the soot enters the reaction zone and burns blue like the rest of the fuel. But if the reaction zone is not very efficient, the soot may escape the flame without burning. Outside the flame, soot cools quickly and drifts upward as black smoke.

Step 2: On Fire Virtual Lab

Open the On Fire Virtual Lab from PBS. Make sure you click through and complete all 4 parts:

  1. Strike a Match
  2. Chain Reaction
  3. Shuffle Atoms
  4. Flame Experiment

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With so many people “going green,” the demand for an alternative to the internal combustion engines (ICE) of traditional, gas-powered vehicles is ever-increasing. Automakers, including Tesla, Chevrolet, Ford, and Mercedes, are responding to the demand and producing more hybrid and electric vehicles (EV). Over the last several years, it's become common to spot these electric and hybrid vehicles on the road!

Using what you've learned in the lesson, compile a list of 5 pros and 5 cons for both types of vehicles: internal combustion and electric. You may also do additional research to find other resources, should you need to. After completing your pro/con lists per vehicle type, formulate an opinion. Post your opinion in the 3.02 Gas-Powered vs. Electric Vehicles Discussion.

Your discussion post should include:

  • Why you think people might choose to purchase an electric or alternative energy vehicle instead of a traditional, gas-powered vehicle with an internal combustion engine.

  • Which kind of vehicle you would prefer to have and why.

  • A list of your 5 pros and 5 cons for vehicles with internal combustion engines.

  • A list of your 5 pros and 5 cons for electric vehicles.

  • Your formulated opinion addressing the first two bullets should be a minimum of 7 sentences, not including the pro/con lists. Please use complete sentences.

After submitting your discussion post, respond to at least 2 other students' posts. Your responses should be at least 2 sentences. You should indicate if you agree or disagree with your classmate's opinion and why.

In addition to the resources from the lesson, you may use the following resources to help you complete the pro/con lists and/or formulate an opinion. You may also choose any other reputable website or print information you may find.

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