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How a Hydrogen Fuel Cell Car science kit works!
A great way to get kids and teens interested in physics and alternative energy is with a Hydrogen Fuel Cell Car science kit. Not only do they have fun building a moving, working, car model, they also learn the basic principles of a potential fuel of the future with these science kits. They may even end up becoming one of the future scientists who help to make hydrogen a viable energy source! This is a wide open field of science as many alternatives to the current gasoline model of vehicles are being studied and experimented with. We consume conventional petroleum based fuels 100,000 times faster than they are being made available, raising many questions about how long our conventional energy supplies will last. The rapid depletion of such fuels associated to increasing energy needs from highly populated nations such as China and India means energy prices will inevitably increase beyond today's benchmarks. Could hydrogen power be the future?
Using a device called a hydrogen fuel cell, the chemical energy of hydrogen can be converted into electrical energy we can use. It's similar to a battery, which also converts chemical energy into electrical energy. However, a battery has a fixed amount of chemicals inside it and a hydrogen fuel cell can continuously have hydrogen and oxygen added to it. Sounds simple, right? Not exactly. There are still many hurdles to leap before hydrogen cars become mainstream. Many of the top scientists and engineers all around the world are in a race to overcome a number of commercialization and technical issues with hydrogen fuel cells and most automakers including GM, Ford, Toyota, and Honda are all researching the potential of this amazing source of energy.
But exactly how does a hydrogen fuel cell work? The Fuel Cell Car kits, such as the ones sold by Science Store by the Stars, contain a reversible PEM fuel cell which means Proton Exchange Membrane. Being reversible, the fuel cell can operate both as an electrolyser, producing Hydrogen (H2) and Oxygen (O2) from water (H2O), and also as a fuel cell (reverse electrolyser) to convert the chemical energy of Hydrogen to electricity with the by-product being water vapor and heat.
Let's look at the first process - the electrolyser. This is the process of breaking water (H2O) into hydrogen (H2) and oxygen (O2). When a chemical charge is applied to water, the charge breaks the chemical bond between hydrogen and oxygen and creates charged particles called ions. In this case, positively charged hydrogen ions and negatively charged ions are formed. An electrolyte, also called an electrolytic conductor, is a conducting medium in which the flow of current is accompanied by the movement of matter in the form of ions. An electrolyser has 2 electrodes where the ions form. One electrode, called the anode, is positively charged, and attracts the negatively charged oxygen ions. The other electrode is called the cathode and attracts the positively charged hydrogen ions. But to break the bonds of water requires energy.
The second process is the fuel cell, or reverse electrolysis. This is the process of turning the hydrogen (chemical energy) into electricity to power our car. The PEM fuel cell consists primarily of four components, the anode (negative electrode), the cathode (positive electrode), a catalyst and an electrolyte. Hydrogen gas pumped into the anode strikes the catalyst (a thin layer of platinum) and splits into hydrogen protons and electrons. On the opposite side of the fuel cell, oxygen enters the cathode. Sandwiched between the anode and cathode is a thin electrolyte membrane that looks like plastic wrap you'd find in your kitchen. It permits the positively charged protons to pass through from the anode to the cathode but blocks the negatively charged electrons which are forced to flow through an external circuit to form an electric current. When the electric current returns from doing work, such as powering an electric motor, it reacts with oxygen and the hydrogen ions at the cathode to form water and heat. That means no smog-forming emissions or greenhouse gasses!
The PEM actually dates back to 1839 when English physicist William Robert Grove first demonstrated his "gas voltaic battery." His experiments paved the way for the PEM fuel cell first developed in the 1960s by General Electric which provided electric power and drinking water onboard the Gemini spacecraft.
What makes Hydrogen fuel so attractive? As mentioned before, the only by-product is water, so there ais no carbon or other emissions to harm the environment. It is non-toxic, clean to use, and holds much more energy per unit of weight than any other element we know. It is also the least complex and most abundant element of our visible universe so we know we won't run out any time soon! And Hydrogen may one day power not only our homes, but even small electronic devices. The limits are only in our minds.
What are the downsides? The major downside to hydrogen powered vehicles is the energy needed to create the hydrogen. Although a car than runs purely on hydrogen is not emitting any pollution, the hydrogen you just bought to fill your tank had to be created using electricity in some form. If a coal, oil, or gas plant created the energy, then plenty of pollution was created to make the hydrogen. All of a sudden your "green" car isn't so clean, is it? If you're using a hydrogen/gasoline hybrid, you’d use less gas, but you'd still be using gas. Also, PEM fuel cells don't create much energy. To get enough energy to power a car, for example, engineers must stack hundreds of fuel cells together in a series. This means a more complicated system with more ways for something to break down. And how much are you willing to pay for a hydrogen car? Because the technology is so new and hydrogen cars are not being mass produced, the price alone will be too much for the average American to afford, at least in the near future. Availability of filling stations is another issue. It will be very costly to install hydrogen filling stations to the same degree as we currently have gasoline stations. Currently, the easiest places to find a hydrogen filling station is in Orange County, California, Westchester County, New York, or Washington, D.C.Travel more than a hundred or so miles outside these areas and you may get stranded. These are just some of the issues that are waiting to be solved by a future scientist.
What advancements are to there to be made? Plenty! Auto companies are looking into creating hydrogen without using carbon emitting sources like coal plants. Solar power is one consideration being investigated. However, solar panels are currently not very efficient (another great scientific field of study) but would be a clean renewable source of energy to produce the hydrogen if it can be done cheaply and efficiently. There are many advancements to be made in the fuel cell design itself. Honda solved one problem simply by re-orientating the position of the fuel cell. Traditionally, fuel cells were placed lying flat under the floor of the car which meant the water created as a by-product needed to be aggressively pumped out of the fuel cell using more energy. Honda's FCX hydrogen car has a vertically oriented fuel cell, allowing gravity to do much of the work and saving energy. Wasn't that a great idea? The size and efficiency of the hydrogen engines is another area where future improvements will be important as well as better ways to cool the engine.
As you can see there are a many opportunities in the science field of hydrogen fuel cell development, and it's a very interesting subject. Although some of this may sound complicated, it becomes much easier to understand when you're building, hands-on, the actual Fuel Cell Car model. Hydrogen Fuel Cell Car kits are popular for kids starting at about age 10 and up and are great science fair projects. Even many adults find them fascinating and they're a fantastic way to participate in a project with your child. And whether they become the next great scientist or not, it's just a fun way to learn science!
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