If you have an old camera, radio, computer or some other electronic device that is broken or you no longer use, take it apart. Disassembling allows kids an opportunity to see the inner workings. Even if you don't understand how every part works, or if you're unable to put it back together, familiarity with how these pieces fit together to make something so useful is a valuable experience. Plus, it's always fun to destroy things.
This is a fairly simple project that requires only a few inexpensive materials. It's also a well-known project with instructions that are easy to find. The process allows kids to explore concepts of electricity, magnetism and energy transfer.
Most people are surprised to learn they can build their own telescope. In reality, a telescope can be built with mostly common and inexpensive parts. Only the lenses require a little more investment, and usually must be ordered. There are several resources that provide information about how to build a basic telescope and how to order lenses. Surveying the planets and stars is even more exciting when kids know they've built the telescope themselves. Not only do they learn about astronomy, but also concepts of optics and light.
There are several websites that offer fun and educational technology activities for kids. For example, HowStuffWorks.com provides tutorials for technology concepts for adults and kids alike. The website also has a child-friendly version with lessons and activities at Express.HowStuffWorks.com.
Science and technology centers and museums provide excellent exhibits for kids to explore. Many of them even have hands-on experiments of all varieties. A science museum can act as a kind of technology buffet, where kids can sample different technology concepts and pick which ideas fascinate them the most.
Computer programming might become as common for future generations as learning another language. Some simple programming languages are ideal for kids to learn the concepts and logic, such as Squeak and Logo. Ideally, this activity should be targeted toward older kids who have a firm grasp of basic mathematics and are comfortable on a computer.
This is another classic technology activity that teaches about cameras, light, optics, and even chemicals. While creation of the camera itself is entirely from common, inexpensive materials, you will need to invest in photo paper and find a way to develop the photos, either by obtaining the developing chemicals yourself, or employing the help of a photographer friend.