Crocus growing in water
By Morgan Turano, science editor
For guardians: Grades 2 & 3 Science lesson
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This Activity
In this activity, students will determine what plants need to grow, with a little help from you. Students will expose store-bought celery to water and sunlight to confirm that plants need water and sunlight to grow. All the instructions for growing the plants and recording results are found in the student section of this handout; sample answers can be found below.
STUDENT VERSION: Check out the student-facing version along with a printable version you can give your student
Time Frame For Completion
The activity is made up of two experiments (Part 1 and Part 2), which each take a week to complete, in about 10 to 30 minutes per day.
During each experiment, the students will set up their experiment for approximately 30 minutes on Day 1. Then, on Days 2 through 7, the students will need about 10 minutes per day to record their observations of the experiment. After Day 7’s observations are complete, the students will spend about 10 minutes answering some questions about their observations from the week. Third-graders will also require another 10 minutes to answer their additional questions regarding how traits can be influenced by the environment.
The experiments can be run concurrently, or during two separate weeks. We recommend that the questions after each experiment be answered on the final day of each experiment rather than on a subsequent day, so that students do not forget their results.
Background Information
Hydroponics is a process by which plants are grown without soil. Plants require only water, air, minerals, and sunlight to grow. Students will be able to see hydroponics at work when they regrow cut celery by placing it in fresh water and giving it sunlight.
Performance Expectations (NGSS)
This lesson addresses the following Next Generation Science Standards (NGSS) for Grade 2:
- 2-LS2-1: Plan and conduct an investigation to determine if plants need sunlight and water to grow.
This lesson addresses the following Next Generation Science Standards (NGSS) for Grade 3:
- 3-LS3-2: Use evidence to support the explanation that traits can be influenced by the environment.
Tips and Safety Information
Tips for storing cut celery: This experiment requires four celery ends, which means you will have a lot of cut celery stalks left over during this experiment. To store celery stalks to eat later, wrap them unwashed in foil and keep them refrigerated. This will help them stay fresh longer. Wash the celery when you are ready to eat it. When you prepare to eat the stalks, if you find they have wilted, cut a half inch off both ends and place them in cold water for a half hour. This will help the stalks rehydrate and make them less wilted.
Tips for Experiment 1: Do Plants Need Water?
Measure 1 inch from the bottom of jar A and draw a line at this height around the jar with a permanent marker. This will help students add the correct amount of water each time they need to change it.
Tips for Experiment 2: Do Plants Need Sunlight?
Measure 1 inch from the bottom of both jars and draw a line at this height around each jar with a permanent marker. This will help students add the correct amount of water each time they need to change it.
Tips For After The Experiments
If your students want to keep growing their celery, it is recommended to plant the celery in soil because leaving the base of the celery sitting in water for a long period of time will eventually cause it to rot. Tips for planting the celery can be found online.
Please note: This experiment requires celery to be cut with a knife. Adults should handle the cutting of the celery to ensure their students’ safety.
Sample answers
Experiment 1: Do Plants Need Water?
Table: Students should write or draw what the plants look like each day for a week. It is expected that the plant in jar B (the one with water) will begin to grow within 2–3 days and will continue to grow as long as water is present. It is expected that the plant in jar B (the one without water) will not grow as long as no water is present.
- Yes.
- No.
- The plant in jar A grew more.
- Yes.
- Because the plant with no water did not grow.
- It will keep growing.
- It will stop growing.
Experiment 2: Do Plants Need Sunlight?
Table: Students should write or draw what the plants look like each day for a week. It is expected that the plant in jar A (the one with sunlight) will begin to grow within 2–3 days and will continue to grow as long as sunlight and water are present. It is expected that the plant in jar B (the one without sunlight) will not grow as long as no sunlight is present.
- Yes.
- No.
- The plant in jar A grew more.
- Yes.
- Because the plant without sunlight did not grow.
- It will keep growing.
- It will stop growing.
Additional Questions for Grade 3:
- I do not think it would grow taller that week. Plants need water to grow. If the plant does not have water, it will not grow.
- I think the plant in the window will keep growing taller. The plant with no sunlight will not grow any taller. I think this is because plants need sunlight to grow.
- Yes, you can change how tall a plant grows by changing the amount of sunlight.
- Yes, you can make a plant stop growing by not watering it anymore.
- The environment changes how tall the plant will grow. Height is a trait of a plant. If there is no water or no sunlight in the environment, the plant will stop growing taller.
READ MORE: Learn about other fun lessons at Victory’s home lesson page.