Why do Leaves Fall?

Time to Experiment!

For this science activity your child(ren) will learn about why leaves fall off of the trees.

​

• To begin, if possible, take your child(ren) for a walk. While you are walking, examine the trees. Are there still leaves on all of them? Are there leaves on the ground? What colors do the leaves have (if you did the color-changing experiment  you can remind them why/how the leaves change colors).

  • Ask them why they think the leaves don’t stay on the tree all year long.

  • At this point you could write down their ideas

  • Then pick up a leaf from the ground, and ask your child to really observe it and tell you what they see. Do they notice the stem? The veins in the leaf?

  • Ask what they think the veins do. **The simple answer is that the veins carry water that the tree has sucked up through its roots into the leaves.  The leaves then use that water to make “food” for the tree – again the veins transport it so the tree can “eat.”

***Now if you would like to do an example activity of the next portion:

​

Option 1 (a bit more complex)

• Take some ribbon and attach it to a piece of paper (preferably in the shape of a leaf but this is not absolutely necessary).

• Ask your child to (or you can as well) make a tiny cut in the ribbon (not all the way through yet). Then another cut and another until finally you have cut it all the way. What happens? The leaf falls to the ground!

• When it starts getting cold outside the leaves know that their time is near, as temperatures drop, tiny ridges are made at the stem of each leaf (the part that connects it to the tree). These little ridges act like the scissors you used to make the connection less and less strong between the leaf and the tree.  Eventually the tree pushes them off. 

​​

• So why can’t trees keep their leaves all year round? In the cold winter months, trees know they won’t have enough water to keep their leaves and themselves alive so they let them go. If they did not do this, the tree itself would not survive the winter.

Option 2

• Draw a large circle (that can fit all of the people participating) with some chalk.

• Ask one person to stand in the middle of the circle (they represent the tree)

• Everyone else begins by standing close to the “tree.”

• The tree says “oh it’s getting colder.” Everyone surrounding the tree takes a small step back. Keep repeating this until someone steps out of the circle. Then “My leaves are falling!” Continue until all of the leaves have “fallen.”

• Explain that as it gets colder the leaves slowly break their connection to the tree. Once they have broken it completely, they fall down! Trees need their leaves to fall so that they can keep as many nutrients (tree food) as possible so they can make it when it gets really cold out!