To introduce the idea of a biome, I ask the children at the circle if they would like to go visit the biome.  I build a bit of eager anticipation and, then, we go outside beyond the playground.  Animals and evidence of animals as well as plants may be the initial focus.  Guide their observation skills to noticing the air.  Is it moving? What is the temperature?  Dig down into the soil and notice how moist it is.  Find a source of water or go out in the morning to capture some dew.  Notice the warmth of the sun on your skin.  Go in the shade and note the difference in temperature.  We bring containers to collect parts of the biome to bring back into the classroom.      Up until recently, I didn't have a way to collect the energy from the sun.  But here it is!!  You can buy it from this site: http://www.lamplust.com/solar-suck-p-41.html or search on amazon.  You can make it yourself using directions from this site: http://www.spillingbuckets.com/2008/12/how-to-make-homemade-sun-jar.html
Similar jars can be used to trap some air inside, sprinkle some dew off a leaf in another, dig up some soil and organic matter, gather plant material and have an insect "visit" for a while. Now you have found all of the parts of a biome!