Will My Carrot Top Grow Plants?

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Objective

SWBAT investigate the process of growing plants in sand, gravel, or liquid, with added nutrients but without soil (hydroponics).

Big Idea

Can carrot tops grow and change with water?

Setting the Stage

Next Science Generation Standards:

This lesson addresses 2-LS2-1: plan and conduct an investigation to determine if plants need sunlight and water to grow. Students discuss that plants have various structures that function to support survival, growth, behavior, and reproduction. This lesson permits students to investigate the growth of a carrot top. Students learn that a carrot top can produce a plant with sunlight and water.

 

Science and Engineering Practices in the Next Generation Science Standards:

The lesson addresses SP 3: planning and carrying out investigations to answer questions. Students plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence to answer a question.  This investigation is imperative to students because they are permitted to  collaborate in groups to investigate the growth of a carrot top. The groups use the scientific method and science process skills.

 

Background Knowledge:

Students have learned that everything in the environment can be classified as living or nonliving. All living things need food and water, carry out respiration, reproduce, grow, and move. While these characteristics are usually easy to observe in animals, including people, they are more difficult to observe in plants. Plants make their own food and store it for use as needed. The growth of plants are primarily in response to light, water, and gravity.

Materials:

 

 

Engage

10 minutes

At the students' desks, they are provided an envelope with a carrot and I ask the students to make a prediction about what is inside. I record some of their predictions on the board. Then I permit the students to take out the carrot and ask them to observe the carrot. (Students are exploring a carrot.) I remind them to use their senses: sight, smell, and touch.  Students are invited to talk and turn to their partners to observe and predict using the science process skills that scientists use when they work.

Then I ask the students a question: What do carrot seeds need in order to grow? This leads them into the exploration of sunlight, nutrients, and water as things carrot seeds need to grow.

Explore

20 minutes

At the students' desks, they are informed that they will conduct an investigation to answer the question: Can a carrot top grow a new plant?  

Students are placed in 4 groups of five to begin the carrot top experiment, which is important for collaboration. I assign the leader, an advanced student, but the group decides who will record, manage, report, and measure.  The students will be provided their group labels and lab sheet at their table.

Groups are at the table, with a carrot, water, and a clear container.  I ask them: What questions do you have about the items? I tell them to formulate questions that focus on what they observe. For example, How can water help the carrot grow? I remind them to look at the question stem poster.  The chart is displayed to help students  developing questions. They record their responses on their lab sheets.

Next, I discuss the following safety rules with the students- 1. Think Ahead  2. Be neat. 3. Be careful. 4. Do not eat or drink materials used in the experiment. The rules are discussed to make sure that they understand a sense of what is and not appropriate during their investigation. 

Students are asked: "What effect will water have on the carrot top? " Students are then instructed to do the following: Write a hypothesis using a "IF and Then" statement.

Students are asked: What things are needed to do the test?; What steps can you take to do the test? Students write their responses while I walk around to make sure that all groups are on task and offer assistance if needed.  Students are instructed to show me their steps before they can do the test. 

Once I observe the steps, the students conduct the test. I make sure that students put the carrot top into the container with the cut side down and they add enough water to cover about half the carrot top. Also, groups place 4 toothpicks in the carrot top, all corners.  The toothpicks are placed in the the carrots to secure them in the cup. I assist the students as needed.  Last, they place the container in a well-lit area by the window.

 

Explaining

5 minutes

Draw conclusions. Communicate results.

This experiment takes five days for the students to complete. Each day, the groups observe their carrot top growths by measuring and recording their findings. A group member uses a ruler to measure any growth that the groups may observe, and the recorder records their findings on the data chart. 

On the 5th day, the groups draw a conclusion about their observation. They look at their data chart and their hypothesis. They decide if their hypothesis is correct or not correct. Then they write an explanation to communicate their results with others. Drawing conclusions are important to my students because they learn that scientists can test their hypothesis and determine the results.

Look at our carrots growing!

Students continue to observe the carrot tops for several weeks so they can see the growth and take care of the carrot top as well.  The big take away for my students is that the carrot tops are growing in water and not soil.

Evaluate

10 minutes

After the fifth day of observing and writing data about the group's carrot top, the groups draw conclusions and report out. Students discuss reasons for the plant growth.

I introduce the word hydroponics by teaching them a clapping song. I sing the words to the students’ hydro (clap, clap, clap) ponics (clap, clap, clap). Hydro (clap, clap, clap) ponics (clap, clap, clap).  Plants can grow (clap, clap, clap) without soil (clap, clap, clap) plants can grow (clap, clap, clap) without soil (clap, clap, clap). I use this song as a fun way to motivate students and teach them the vocabulary term, hydroponics. Also, students learn that the carrot tops grew because the water, sunlight, and air, not soil.

Students singing Hydroponics.

I collect the lab sheets to make sure that the groups successfully complete them. I am observing to make sure that the groups noticed that their carrot top grew a new plant without soil but with water.