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Journal Red Warrior's Journal: ask {/.}: Science fair projects 11

Journal by Red Warrior

My son needs to do a school science fair (5th grade) project. He has decided that he wants to do something WRT radio/radios/radio waves. We've built a few simple receivers, etc. over time, and it interests him. He's got almost 6 weeks to work on his [NB It will be HIS project, :-)] project, so time isn't an issue. Actually, he's a kid after my own heart, so it will become an issue in about 5 weeks...

The catch - We are both stuck in the "build something cool and explain how it works" mode of thinking. However, the purpose of the science fair is that whole newfangled "scientific method" thingy. You know, a question, a hypothesis, a controlled experiment, and evaluation of the results. Along with documentation of materials and procedures at a level that allows the experiment to be replicated from it.

So... Any of all y'all think of a good age-appropriate radio-related experiment?

Btw,
[rant]I'm generally opposed to throwing more and more money and/or tech at schools, as opposed to, you know, TEACHING children. Generally, it seems that the educational establishment spends way too much time and effort in figuring out how to make it so that learning happens magically.....[/rant]

However, this, and similar initiatives are cool. The DLC is used by my sons school district. Which consists of three schools and a district office. Which all share the same parking lot. Some of the instructors and support personnel (such as my x, the school psychologist) are shared with the neighboring school district, 20 miles away.

It definitely expands the options available to students of all ability levels and interests. Fer instance, there's no reason to believe that BFE school district would ever be in a position to offer a latin class, let alone two year's worth.

This discussion was created by Red Warrior (637634) for no Foes, but now has been archived. No new comments can be posted.

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ask {/.}: Science fair projects

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  • Build yourself a receiver that can measure the strength of the 802.11 network in a given spot. Make some predictions about the strength of the signal in various parts of your house/yard, based on the types of materials and distance between the spot and the base. Use your receiver to verify / falisify your predictions.

    Obviously, you can also buy meters to measure signal strength, but you did day you weren't interested in just throwing tech and money at the problem.

    • Something similar would be a radio inside a foil lined box. If you have a way of measuring the strength of the signal outside the box, you can build a window and put various materials in front of the window. Posit a theory on which materials are more opaque to radio waves, and test it.

      Instead of foil, you could use unetched circuit board material. On eBay though, I don't see much. All the stuff for sale is precut into small panels.

      • Thanks.

        The radio waves one just might be a winner. He could build a small transmitter pretty easily from a kit, since CW would suffice, and hook up a signal meter to the external receiver to measure signal strength. Just need an empty & accessable freq. Probably go with multiple lidded boxes that the transmitter could be placed in... I'll call him tomorrow and see what he thinks about that one.
  • He could build a Yagi antenna [wikipedia.org] for a given frequency and try to find the point at which adding reflectors and directors reaches the point of diminishing returns (in other words, at what point does adding elements become mostly pointless). Yagi's can be both relatively easy and fun (nerd's definition). I recommend The ARRL Antenna Book for a reference. I'd pick a relatively high frequency range, such as VHF or UHF. If you use something in the HF range, he'll end up with 20m+ elements.

    Maybe he could pick an 80
    • I had also had an idea about antennas, but mine is pretty cheap/simple to setup: do those booster antennas that you see in the store work? (I am thinking of TV ones in particular, but I suspect there are booster antennas for everything on the planet). Plunk down about $40 on a few different models and see if any of them work. It would probably be a good lesson in economics too, since I would bet that the most expensive one probably won't work much (or any) better than the cheaper ones. Of course you could a

  • Very simple experiment. Maybe too simple. The question is: how do I block all radio sources? Theory: Faraday cage [wisegeek.com]. You could experiment with different materials and dimentions. Talk about the applications of a Faraday cage (like this [physlink.com]).

    Design and build a Waveguide from a tin can [turnpoint.net].

    Repeat Hertz's First Radio Experiment.

    Antenna lenght/shape and signal amplitude.

  • How about combining the WLAN stuff with a dash of Myth Busters type fun?

    I'm thinking "Does a 2.4 GHz cordless phone really interfere with a standard home WLAN cable router?" You've got a hypothesis and a theory built right in. Testing becomes the sticky part. Mainly you'll have to define what "interfere" is for the experiment and also the methodology for the tests.

    All in all it could be fun.

    • I'm thinking "Does a 2.4 GHz cordless phone really interfere with a standard home WLAN cable router?" You've got a hypothesis and a theory built right in. Testing becomes the sticky part. Mainly you'll have to define what "interfere" is for the experiment and also the methodology for the tests.

      WiFi gear and cordless phones (2.4-GHz and otherwise) each operate on sets of channels (one channel out of 11 for WiFi, probably some different number for your phone). An experiment could be constructed around go

      • Heh, didn't notice your .sig before. I can see it now: Cheney's latest song soars straight to the top. Or, #1 with a bullet as they used to say...
  • audio frequency radio waves are kind of fun, but i don't hear that much about them. the receiver is easy since you just convert the signal from the antenna straight to audio.

    if i were actually helpful, i'd also think of something cool to do with them, like the difference in interference of materials or how to make them. maybe you could do a comparison of audio frequency waves and the interference it creates in am radio, sort of like crappy old car stereos that got interference from the engine electrics.

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