What are good materials to generate electricity from?

Question

I'm thinking of generating electricity from various objects and comparing the results as a science project. However, I need examples of things to test and compare. For example, food (we have potatoes and lemons already), solutions, and other materials that would normally generate electricity. The person who answers best within the first 2 hours of my posting will get Best Answer. Thanks!!

Answer 1

How exactly are you generating electricity?  

If you are making a battery by putting two metal probes into a piece of fruit or solution, then you are really generating electricity from the metal.  The fruit or solution you are talking about is just supplying the electrolyte and acid to break down the metals and transfer the ions. The actual energy is coming from the energy that is chemically stored in the metal, not from the fruit itself.  You should explain this as part of the science project.  In that case, you could try oranges, mangoes, peaches, salt water, vinegar, carbonated water, and pop.  You could measure the pH of the fruit or fluid, and measure the resistance with an ohmmeter.  electric generation might have more to do with acidity and resistance than anything else.

There are other ways of generating electricity and I'm not sure if you are considering any of these because you did not specify.  You can make static electricity by rubbing different materials together (such as plastic and fur).  Electricity can also be generated from food by making fuel such as ethanol out of it, or burning it directly as biomass.  Any food will do this, but might be hard to do as part of an experiment.

If you give more details about exactly how your are making electricity maybe we can help you more.

Edit:

I'm still not exactly sure how you are planning on doing your project.  Electricity for home use is produced by generators.  Generators require a power source to turn them.  Usually this is done with turbines.  Turbines can be wind or hydroelectric turbines, or they can be steam powered.  Steam power can be run by anything that burns or produces heat: coal, wood, food, alcohol from food, leaves, fibers, grass, etc.  Steam turbines can also be run by nuclear energy.  You would not be able to actually run these as an experiment by yourself, however, because it would take a lot of time money, and safety precautions.  Even a homemade wind turbine would be expensive to make.  As an experiment, however, you could burn a number of different materials to heat a pot of water and see how much heat a certain weight of each material produces.

If you are trying to actually power a lightbulb by yourself for your project, you have fewer options.  use an array of solar cells.  You could use a bicycle powered dynamo (small generator) to run a light--which is ultimately powered by the food you eat.  Lastly, you can make your own battery.  That's what I was tryint to explain above with sticking two metals into a fruit.  Basically you need two metals (like two coins of different type) and an electrolytic liquid (which helps if its acidic).  Most of our household elecrolytes and acids are food-grade, but you can use battery acid which can be bought at the hardware store.  Look at the wikipedia article about homemade battery cells.  The problem with homemade batteries is that they are very inefficient and you might have trouble powering a lighbulb with one unless you hook up a whole bunch of them together.