This week's experiment grew out of yard work. I was trimming the bushes around our deck and started thinking about plant growth, especially about which part of the plant grows. That lead to the question that I have for you. If my grandfather had carved his initials in a young tree 50 years ago and I looked at that tree today, what would have happened to the carving? Would it be high up in the tree? Lets find out. You will need:

• a plant that grows quickly
• string or yarn
• a ruler

Find a plant that you want to test. The experiment will work faster if you use a plant that is growing quickly. Look for a plant with lots of new leaves. Tie the string around the stem, between the end leaf and the next leaf. The string will act as a marker, to help us see which part of the plant is growing. Measure the distance from the string to the end of the stem or branch. Now, all you have to do is wait a few days, while the plant grows.

What can the string tell us? If the entire branch is growing longer, then the string should stay at the end of the branch as it grows. On the other hand, if only the tip of the branch is growing, then we will find that the string is no longer at the end of the branch, but in the middle. Which do you think it will be? Try the experiment to find out if you are right. Then you should also know what I would see if I looked for my grandfather's carving.