Science Experiments for Kids

Capturing Leaf Vapor

Capturing leaf vapor can help answer kids the question, "Do leaves actually breathe?" This science experiment for kids focuses on measuring the amount of water vapor that a leaf releases into the air in a week.

Trees drink water through their roots and send it up to all parts of the tree. Leaves use the water they need and "breathe" out the excess in the form of water vapor. This experiment uses a plastic bag to catch and measure the vapor from a leaf.

What You'll Need:

  • Plastic sandwich bag
  • Twist tie
  • Small pebble
  • Measuring spoon

Step 1: On a warm, sunny summer day, put a pebble in a plastic bag and place the bag over a tree leaf that gets a lot of sun.

Step 2: Secure the bag over the leaf with a twist tie.

Step 3: After a few hours, return to observe the leaf. You will begin to see moisture collecting inside the bag.

Step 4: Leave the bag on the leaf for a week.

Step 5: After a week, take the bag off and carefully measure the water inside with a measuring spoon. This will tell you how much water vapor your leaf has produced in a week's time. (A small leaf will produce approximately 1/4 teaspoon of water in a sunny week.)

Salt and sugar look alike, but they are different in a lot of ways. Go to the next page for look-alike tests for salt and sugar that you can do to identify how their molecules act differently.

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