signsfall

SIGNS OF FALL

Overview: In temperate regions, people can observe the annual change of seasons. In autumn, leaves of many trees turn color and fall to the ground, many animals migrate or go to hibernation, the days get shorter and the aair gets colder. The pattern repeats intself every year.

We couldn't go outdoors for this activity since in was cold and a bit rainy. Luckily, we had already picked leaves another day with Miss Moenke. Our docent, Grace (who travels in her job), brought us leaves that she had picked in Chicago and Washington D.C. We talked about different types of leaves. We compared lobed multi-pointed, serrated, rounded, heart, tapered, rounded, simple, and compound.

We talked about how the cells at the base of each leaf stem begins to die, forming a barrier that keeps water and nutrients from traveling to the leaf. Chlorophyll, the green color in the leaves, starts to break down, and other leaf colors begin to show. When this happens, you see the leaves changing into bright red, purple, orange and yellow that we see in the fall.

To teach us how this happens, Grace tore up green leaves and placed it in the bottom of a jar and covered the leaves with rubbing alcohol. Then she hung a cut-up strip of coffee filter from a pencil on the top of the jar. When the strip soaked up the alcohol, we observed if there was any color on the strip. Our experiment was not successful because we were expecting to see some color on it. We think that the leaves we used didn't have enough pigment. What Grace was trying to show was that the other colors; yellow, red and orange are always in the leaves, but are usually covered by the green color from chlorophyll. In the fall when the leaves no longer produce chlorophyll, the other colors show through. You can try this experiment if you like, but make sure your parents or your teacher helps you.

We also took the leaves, which we gathered, and made leaf rubbings by putting the leaf under a piece of paper and rubbing colored crayons on top. Here are a few.

By Angela

By Dava

By Robin

By Dan