This idea was adapted to suit Autumn time.  

Items you will need:
Water, baking soda, spoons, food coloring, vinegar, a cookie sheet, and 6 cups.  And different colored leaves.


Stick different colored leaves on the chalk board.  Each leaf has a song to sing on the back
Put 2 drops of food coloring on each spoon.  Over the food coloring place baking soda (you want the baking soda to hide the food coloring).  Put water in each cup -except in one, put vinegar.  Choose a child to pick a spoon and let them choose a cup to stir it in.  Whatever color the water turns pick that color of leaf.  If they choose the vinegar cup, let them pick their favorite song to sing! 
Colors: Purple, Red, Yellow, Blue, Green, Orange.
Have fun!!!