Many kids, including adults, find plants rather dull and uninteresting. Fire up interest with some of the following thoughts.
What would the Earth be like without plants? Draw kids to consider that plants are the organisms that can capture light energy and use it to power all their growth processes that construct raw chemical nutrients (largely carbon dioxide and water) into the organic materials of their bodies. All animals, including humans, depend on that organic matter for energy and growth. In short, our survival depends on maintaining a healthy, reproducing biota of plants. Survive on eating animals! What are you going to feed those animals? Conclusion: Without plants, the Earth would soon become lifeless mass of bear rock, dirt, and water.
How many different kinds of plants are there? Consider different kinds. Plants range in size from microscopic alga to giant trees. There are millions of different species. Photos showing some of this diversity can be found by typing into your browser:
algal diversity images
plant diversity images
Over the course of history a relative handful of plants have been selected out of the wild and bred for agriculture and horticulture. Type into your browser:
plants used in agriculture images