Thanks to modern technology, there is now a fun activity that combines satellite navigation, orienteering, computer skills, treasure hunting...and walking. It's a super cross-curricular game that your students will love.

Called "geocaching," (pronounced "geo cashing") it makes use of GPS units to find prizes hidden by other geocachers.

WHAT IS A GPS?

GPS stands for "Global Positioning System" and these handheld electronic units make use of satellites to pinpoint your latitude and longitude to within three meters. A GPS will help you navigate from your current position to another location using their built-in maps and instructions.

GPS units cost anywhere from $100 and up. As an alternative, some Blackberry units can be GPS-enabled. You can download "Geocache Navigator" for free for 60 days. For more information, see the "Blackberry.Geocaching" website.

However, the big surge in GPS use will come when regular GPS-enabled cell phones hit the market. It is estimated that 500 million such cell phones will be in use, worldwide, by 2012.

GEOCACHING - HOW TO GET STARTED

To start a geocaching quest, log in to the "Geocaching" website. Enter the postal code of your area and you'll see several local cache locations, each with a short verbal description, a level of difficulty and a location shown on the Google Map website.

To get your GPS co-ordinates, you must first register (it's free). You can then receive the GPS longitude and latitude co-ordinates. An example might be N43o40.110'W083o23.378'

Your job as a geocacher is to enter the co-ordinates into your GPS unit, then follow the directions to the cache. This will involve a nice hike for your students.

Before embarking on your quest, you could give a cross-curricular lesson on latitude, longitude and satellites...not to mention the use of the world wide web.

ONCE YOU FIND YOUR LOCATION - WHAT TO DO?

Your GPS will get you within 6 to 20 feet from your target. You then have to search to find the cache, which usually will be a plastic container.

Most containers will contain a dollar-store item such as a plastic animal, pencil or measuring tapes. They will also contain a logbook that you can read, and then sign. Seeing who else has been to the cache is half the fun. Take the prize, then replace it with a prize of your own.

CLASS LOGISTICS

You can go geocaching with your entire class, or split into groups, as long as each group has a supervisor. Also, you could also establish a cache or two of your own, in a location you know to be safe and easily accessible.

The good thing about a GPS is that it's hard to get lost when you have one in your hand. It will leave a trail of "bread crumbs" as you walk - little dots on the display screen that show you how to retrace your steps. However, it's also good to bring a compass, just in case the GPS batteries die.

And the best thing about geocaching? It will get your students walking - and make it fun at the same time!