Can Plants Grow Without Sun or Water?

Description

This lesson provides examples of how plants are dependent on light and water to survive.

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Lesson

Big Question: Can plants grow without sun or water? 

At Hidden Villa, farmers grow produce to provide food for the community, themselves and the animals on the farm. One problem farmers and gardeners face is how to provide their plants with the things they need for growth throughout the different seasons. In order to do this, farmers must know what plants need to survive and grow. 

Students will work collaboratively to plan and conduct investigations to answer the question of whether plants need water and sunlight to grow.

The following activities assume that students are keeping science notebooks. Notebooks are a great way for students to model what scientists do in all disciplines. They get to think, record and reflect like scientists do. This is also a great way to enhance student’s writing skills and can be used as an assessment of student progress.

Give students time to brainstorm what they know about plants in their science notebook. On the board or butcher paper, make a list of all the things students know about plants. Do not correct misconceptions at this time. Students will no doubt mention things that plants need to survive. Tell students that they are going to collect data through observation and investigation to back-up their knowledge about plants.

Activity: Where do plants grow?

Students will practice making observations. Give students the chance to explore their school yard, or a surrounding area with the specific instruction of observing where plants are growing and where no plants are growing. They should take notes in their science notebook. Prompt them to be as descriptive as possible (this can include drawings).

As a class, determine if there are any commonalities between where students found no plants growing, few plants growing, and a lot of plants growing. Do these observations support or refute the prior knowledge the students had about plants? Where was the area with the most water? What about the area that received the most sun? Are there any questions we have about plants based on the observations we made? Keep a list of these questions where it can be referred back to.

Video: How to Keep Plants Healthy

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Hidden Villa children’s gardener, Nicolette, explains how she keeps the plants healthy by providing them what they need to grow. Have students watch the video through one time. The second time through ask them to compare and contrast the garden during winter and spring. They can draw a Venn diagram in their science notebook and write down bullet points as they watch. Prompt them to use descriptions of the weather, the state of the garden, and what the gardener does to help the plants grow in either season. You can pause the video on the split frame of the garden at both seasons to allow students time to make observations. They can practice cause and effect by describing how the garden reacts to the different weather of the season and even how the gardener effects the garden throughout the year. Practice using cause and effect sentence frames such as: “If it sunny then the plants will grow.” “If it does not rain then the gardener will water the plants.”

Class Investigation: Will it grow?

Materials:

• One small plant per student (all plants should be the same type and of similar size)
• Beaker for measuring water

Ask students how they can answer the question if their plants will grow without water. What about without sun? Students will develop an investigation plan. Some features to consider are: What type of plants they should use? (Note: in this case it is better to use a plant rather than a seed, which can germinate in the absence of light because of energy stored in the seed). What is the light source? How will they keep plants in the dark? How much water should be given to the plants? How will plant growth will be determined? Although students do not need to know the vocabulary of experimentation such as control or variable, they will need to understand that their investigation will not be accurate if all conditions beside the one being tested are not kept consistent.

Students should write out the materials and procedure in their notebook.

Students can work in groups of four for this investigation. Each student can label their plant A, B, C, or D. Students will collect evidence to help them answer the questions. Each student will be responsible for tracking the growth of one plant. The four plants should be tracked under the following conditions:

• Plant A: Provided with both light and water.
• Plant B: Not provided light but provided water.
• Plant C: Not provided water but provided light.
• Plant D: Not provided either water or light.

Math Connection: Graphing Plant Growth

Students should keep record of their plant’s growth over two weeks. Decide as a class how often the plants should be measured. Show students how to measure the height of the plant using a ruler. Each student can measure their own plant and keep data in a table in their science notebook. Measure to the nearest whole centimeter.

What other methods are there for tracking the health of the plant (number of leaves, color)?  Students can write and/or draw observations along with the height measurements in their notebook.

Graphing: Students will create two graphs. They will take the data of their own plants and graph making a line plot. The horizontal scale should be the day and the vertical scale should be the height of the plant in centimeters. These graphs will be unique to each student. Students will need different levels of support when it comes to the graph. Some students may be able to draw the graph and label on their own. Others may need a graph template where they fill in the blank for titles and it can be helpful to provide some students a completed graph that only needs points plotted. Students can even create their graph with excel or Google sheets.

Gather data for the final height of the plants of the whole class. As a class, average the data for all Plants A, B, C, and D. Explain that observing multiple plants with the same conditions reduces potential error. Students can create a bar graph to determine which plants grew under the different circumstances. The graphs will look the same for all students.

Conclusion: Under which conditions did the plants grow the most? The least? What is the difference of growth between different plants? How do the graphs make it easier for the students to come to these conclusions? How do the graphs help students communicate the information they learned to other people? Students can solve simple math problems using the data in their graph to support their answers.

Revisit the list of what students know about plants. Are there any changes that need to made, anything to be added? What evidence do the students now have to support their knowledge about plants. Keep this in a visible place while students continue to explore plant life cycle through pollination and seed dispersal.

Standard

2-LS2-1 Science and Engineering Practices

Planning and carrying out investigations to answer questions or test solutions to problems in K–2 builds on prior experiences and progresses to simple investigations, based on fair tests, which provide data to support explanations or design solutions.

• Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence to answer a question.

Disciplinary Core Ideas LS2.A: Interdependent Relationships in Ecosystems

• Plants depend on water and light to grow.

Crosscutting Concepts

Cause and Effect

• Events have causes that generate observable patterns.