Why Do Leaves Why Do Leaves Change Color?Change Color?

Extracting Pigments From Extracting Pigments From ChloroplastsChloroplasts

MaterialsMaterials

LeafLeaf Small clear paper cupSmall clear paper cup Alcohol to fill cup approx. ½ fullAlcohol to fill cup approx. ½ full Paper towelPaper towel Coffee filterCoffee filter Plastic fork or knifePlastic fork or knife

ProcedureProcedure

Flatten filter and place it on paper towel.Flatten filter and place it on paper towel. Using the blunt side of the knife or the fork Using the blunt side of the knife or the fork

handle, gently rub the leaf against the edge of handle, gently rub the leaf against the edge of the filter. Green chlorophyll will begin to the filter. Green chlorophyll will begin to appear on the filter. Continue until you have a appear on the filter. Continue until you have a good amount of green.good amount of green.

Cut from sides of green to middle of filter.Cut from sides of green to middle of filter. Place cut strip into alcohol-filled cup.Place cut strip into alcohol-filled cup.

Procedure (cont.)Procedure (cont.)

Allow the filter/chlorophyll to set in the Allow the filter/chlorophyll to set in the alcohol for at least one hour.alcohol for at least one hour.

Remove from the alcohol and observe what Remove from the alcohol and observe what happened.happened.

ResultsResults

The chlorophyll should have quickly turned The chlorophyll should have quickly turned the alcohol green.the alcohol green.

After approx. 30 minutes, hidden pigments After approx. 30 minutes, hidden pigments should have begun to appear. should have begun to appear.

You might see red, brown, or yellow. Colors You might see red, brown, or yellow. Colors vary, depending upon which pigments are in vary, depending upon which pigments are in the particular left you are working with.the particular left you are working with.

Why Does This Happen?Why Does This Happen?

The green chloroplasts mask the other The green chloroplasts mask the other pigments. They are always there. We just pigments. They are always there. We just can’t see them until cool weather approaches can’t see them until cool weather approaches and photosynthesis decreases. Without food and photosynthesis decreases. Without food production, the green disappears and the production, the green disappears and the masked pigments appear. Eventually the leaf masked pigments appear. Eventually the leaf falls. falls.