Plant Structures

In this lesson, students carry out an experiment to analyze how water affects the growth of plants’ external parts (roots, stem, and leaves) by comparing seeds planted with and without water. Additionally, students analyze the relationship between structure and function as they connect a plant’s structures with their functions, using what they know about the survival needs of all living things.

• Plants have different parts, and each part has a specific job in helping the plant get what it needs to survive.
• Once a seed lands in soil, it begins a predictable cycle that all living things follow as they move from birth to death. Life cycles are different for different living things.

• What does a plant need to survive?
• How do plants get water and nutrients?
• How do plants get the food they need to survive?
• How does food get from the plant’s leaves to the rest of the plant, and how do nutrients and water get from the roots to the rest of the plant?
• Why do many plants have flowers?
• What does a seed need to grow?
• How does the seed grow when it gets enough soil, water, and sunlight?
• How does the plant grow after the roots and stem are there?
• How is the plant’s life cycle evidence that plants are living things?
• What kind of plant will the seeds from carrot plants grow into?
• How does water affect the growth of a plant from a seed?

Misconception: Plants get their food from the soil through their roots.

Fact: The leaves of plants absorb the sun’s energy, which allows them to make their own food through photosynthesis. Water and minerals are taken in through the roots.

Misconception: Sunlight helps plants grow by keeping them warm.  

Fact: The sun’s energy is an important ingredient in the process that allows plants to make their own food. This is why the sun is so important for plant growth.

Flowers : the parts of a plant that make seeds

Leaves : the parts of a plant that collect sunlight and make food

Living : anything that breathes, needs food and water, grows, moves, and reproduces

Plant : a living thing that makes its own food from sunlight

Nonliving : anything that does not meet, and has never met, all of the requirements of life

Roots : the part of the plant that holds a plant in place and takes in nutrients and water from the soil

Seed : a young plant inside a protective coat; needs soil, water, and sunlight to grow

Stem :the part of a plant that holds the leaves and flowers in place; water and nutrients travel through the stem to the rest of the plant

Eating Carrots

Have you ever eaten a carrot? If so, you ate the root of a plant. Many plants have roots. Roots are parts that help the plant survive. Roots often grow underground.

The Job of Roots

Plants make their own food. But they also need water and nutrients to grow. Roots help the plant take in water and nutrients from the soil. Many roots also spread out in the soil. This helps to hold the plant in place. Finally, roots store food for the plant.

Leaves and Stems

Many plants also have leaves. The leaves collect sunlight and make food. The stem is another part of many plants. The stem holds the leaves and flowers in place. Water and nutrients also travel from the roots through the stem to the rest of the plant.

In this hands-on activity, students come up with a question related to seeds and water. They work together to make a hypothesis and record it. Students then carry out their experiment by only giving water to one of the two planted seeds. Students record their observational data from the experiment. Finally, students analyze their data and form a conclusion for their experiment. Students use the data from their tables as evidence to support their conclusion about how water affects a seed’s growth.