Natural Cycles:
The Carbon Cycle
The Nitrogen Cycle
Some things, like a story, begin and end. Other things, like the seasons, don’t really end,
but change and return. Explore natural cycles with a Moebius strip.
1. Cut the 8 strips out of your piece of paper. Give four to a partner and keep 4 for
yourself.
2. Tape 2 of the strips together end to end to make 1 long strip. Do the same thing
for the other 2 strips.
3. For each of the 2 natural cycles, write side A phrases on one side of a long paper
strip and side B phrases on the other side. Side B phrases must start at the same
end that side A phrases start, but are written upside down to side A. Phrases fill a
side and are spaced equally from one another. The beginning of the first phrase
on a side and the end of the last phrase should be slightly in from the ends of the
strip.
a. Carbon Cycle: Side A – living thing dies; decomposers release carbon
into atmosphere
Side B – carbon dioxide taken in by plants; plants form
carbohydrates; plants eaten by living creature
b. Nitrogen Cycle: Side A – bacteria take nitrogen from atmosphere;
nitrogen added to soil; nitrogen used by plants
Side B – plants eaten by living creatures; nitrogen
returned to soil through wastes and remains; nitrogen
returned to atmosphere by bacteria
4. To make a Moebius strip, give a half turn to a strip of paper and tape A to B.
5. Find the cycle’s starting phrase and mark it with an X. Draw arrows from phrase
to phrase until you complete the cycle. The Moebius strip has no beginning and
no end, just as natural cycles involve constantly repeating series of steps.