Here's a simple experiment you can do to show that plants give off gas. You'll need a plant that has runners ... a spider plant works well. Fill a jar with water. Then fill a test tube with water too, and cover the top (so the water won't run out) as you place it upside down inside the jar. It can be supported across the top of the jar with tape. Now take one of the runners and feed it up inside the test tube. Make sure the end of the runner remains underwater. Leave the plant and jar in direct sunlight for a few hours, and you will see the result ... A bubble of gas will slowly form in the top of the test tube. This bubble is oxygen. Plants use sunlight, air, and water to make food. This process is called photosynthesis. While they are doing this, they give off oxygen. We need this gas to breathe, so plants are an important part of our environment. Plants in rainforests around the world produce a lot of oxygen. However, scientists estimate that roughly half of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton ... drifting plants, algae, and some bacteria that can photosynthesize. Resources HTML, graphics & design by Bill Willis 2023