​By the End of This Unit:

​You may not think that plants can grow in a cave. But this forest is in a cave in Vietnam! As long as plants have what they need to grow, they can thrive in even the most unexpected places.

​

​By the end of this unit, you'll be able to explain that plants get their materials they need to grow mostly from air and water.

​Can You Explain It?

• ​When you think about plants growing in a garden, what do you expect to see?

• ​Look at the plants in this photo. They are growing out of tubes.

• ​Think about how and where they are growing. Is this different from what you would expect?

​What the Right Amount?

• ​Imagine that you were trying to grow roses in an area where it doesn't rain very often. How would you make sure the plants got enough water between rainstorms? You would probably water them with a sprinkler system or hand water them with water collected in rain barrels.

​What's the Right Amount?

• ​Irrigation engineers design structures to water, or irrigate, plants. One way to do this is to water plant roots. This type of system is made by burying plastic pipes with holes in them along rows of plants. These systems can be run on a timer so that irrigation occurs during cooler parts of the day. This reduces water loss due to evaporation.

• ​

• ​Then next two slides are also types of irrigation systems.

​What's Needed

• ​Think about two kinds of plants you’ve seen, such as a maple tree and a dandelion. How are these plants similar? Both have leaves and a stem and produce flowers. But how do a maple tree and a dandelion differ? The stem of a maple tree is the trunk, while a dandelion has a soft stem. Plants have similar structures that also have differences.