Celery Experiment

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Objective

SWBAT recognize that stems take in water.

Big Idea

Can you change the color of celery?

Setting the Stage

National Science Teaching Standards

Students need to understand characterization of organisms. Plants have different functions in growth, survival, and reproduction.  It is important that students have the opportunity to investigate how plant parts function in order to grow and survive. If students gain a clear understanding of plants function and structure, they can assist with plants growth, survival, and reproduction. In this lesson, students learn that the stem takes in water for the plant.  They place celery stem in colored water overnight to make an observation on the following day.

Next Generation Science Standards

The lesson focuses on 2 LS1-1, plan an investigation to determine if plant needs sunlight or water to grow. The students need to understand how the parts of a plant function in order to investigate if plants need water and sunlight to survive.

 Science and Engineering Practices in the Next Generation Science Standards

This lesson address SP 8: obtain, evaluate, and communicate information. During the investigation, students will ask their peers questions about the plant, and they will write and communicate their group's results. It is important that students work collaboratively to communicate in written and oral form.

Structure and Function

In this lesson, the students understand that the celery is a stem, and the stem is designed to take in the water and nutrients. This is important for students to know because they learn that plant parts are structured in a way to support the life of a plant. 

 Background Knowledge:

Students have already learned that plants have roots, stems, leaves, and flowers. They know that plant parts function in different ways to help plants grow, survive, and reproduce.  Students collaborate in groups using the scientific method and science process skills (observe, infer, form a hypothesis, predict, draw conclusions, and communicate).  I establish safety procedures during all science and technology investigations.

Materials:

A Stalk of Celery

Red, Blue, Green, and Yellow Food Coloring

5 Tall Clear Cup with 3/4 of water

Plastic knife

Lab Sheet

Group labels

*This lesson will take 2 days*

 

 

 

Engage

5 minutes

While on the carpet, students are asked: How many of you like celery?  I draw a graph on the board with the headings, Like and Don't like. I record the students' answers on the graph. This graph helps students compare data.  The graph was used to motivate and engage students about the lesson.

Then I have students turn and talk with their partners to discuss: What part of the plant is the celery? Students are allowed to communicate with their partner to develop oral communication skills. The students are invited to share their responses.  The students should say the stem. If they do not respond correctly, I show them a plant and ask them: What part of the plant does it resemble? Then students are asked: How does water move through the stem?

 

 

 

 


Explore

15 minutes

At the students' desk, they are informed that they will conduct an  investigation- "How does water travel up a stem?"  Students collaborate in groups.  I tell the students the leader and they decide  the manger, reporter, and recorder. I have assigned the leader which is an advanced student.  The students will be provided their group labels at their table and their celery lab sheet.

I lead groups through the scientific method.

Observe and ask questions- Groups are at the table, they have two pieces of celery, water, food coloring, and a tall clear plastic cup. I ask them: What questions do they have about the items? 

I remind them to look at the question stem poster located in my room.  The chart is displayed to help students with developing questions. They record their responses on their lab sheets.  Some groups are permitted to share their questions, so other groups can hear their peers' responses.

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

Form a hypothesis-  Students are posed with the question: "What will happen when we soak celery stalk in colored liquid?" Students are asked: write a hypothesis using a "IF and Then" statement.

I walk around to provide an example how to write the hypothesis.  I give the students 3 minutes to write their hypothesis.  They are timed so students can stay focused on completing their task. They tend to take too long if they are not timed.

Plan a fair test- Students are asked: What things will you need to do the test?; What steps will you take to do the test? ( Planning Our Fair Test, student video) . 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.  I provide students  7 minutes to write their steps.

Do the test.  Once I observe the steps that students will take to do the test, I permit students to follow their plan to complete.  I inform the students that the colored water must be bright in order to see the change in the stem.

 If you take the stem out, what do you think will happen? I permit the students to share. I inform the students that the experiment takes time and we have to wait overnight to make an observation.

Draw conclusions. Communicate results. (Day 2) -  On the next day, students observe the celery.  I use a plastic knife to cut the bottom of celery about 1 inch, so they can see the food coloring travel through the stem.  They record their findings on their lab sheet. 

 

 


 


 

 

 

 

Evaluate

10 minutes

Day 2

Each group is given an opportunity to share their findings to the class. It is important that students share what they know by telling or showing others to make it relevant for students. This permits them to work on the science process skill, communicate. 

Then I explain to to the students just as people have veins to make our blood flow through our bodies, plants have veins that water flows through. Plants absorb water through their roots through a process called osmosis. Water travels throughout the plant. When we add food to the water, it travel throughout the celery stems and the leaves.