Try this hydroponics STEM activity! Growing plants without soil engages kids in the engineering design process. Instead of one and done, it’s something you can do for months.
Mr. Grow Organizes a Hydroponics STEM Activity
Our favorite fifth grade teacher rifled through his hydroponics unit. Then he stood in front of his class. “What does a plant need to grow?” he asked?
“Soil!” shouted a kid in the back.
“Are you sure?”
Growing Plants Without Soil
Mr. Grow pointed to the side table. “This week in life science,” he said, “we’ll be germinating seeds in baggies. First, you’ll fold a piece of paper towel and wet it. Second, you’ll tape a baggie to your desk. After inserting the baggie, you’ll add three bean seeds. Then we’ll see if plants need soil to grow.”
As his students put their baggie gardens together, Mr. Grow made his own. He carefully stapled an array of baggies to a bulletin board. “Every day,” he told his students, “I’ll add a new set-up to this growing bulletin board. Then we’ll be able to see a progression of germination.”
Each morning that week, kids raced to their desks to check their seeds. As time when on, the seeds swelled. Then the seed coats cracked. Soon, roots emerged.
“Hey,” said the kid in the back, “I guess plants don’t need soil to grow.”
Learning about Photosynthesis
The following week, Mr. Grow taught his students about photosynthesis. They learned about a special chemical reaction. Using the Sun’s energy, carbon dioxide and water molecules rearranged to form glucose, or plant sugar.
Reviewing the Engineering Design Process
That same week, Mr. Grow reviewed the engineering design process:
- Define the problem.
- Research.
- Brainstorm possible solutions.
- Choose the best solution.
- Build a prototype.
- Test and record observations.
- Identify failure points.
- Redesign and conduct a fair test.
Launching the Hydroponics STEM Activity
Soon, the teacher was ready to launch a hydroponics engineering design activity. That morning, he carried bags of containers, plastic bottles, and egg cartons into the school.
“What on earth?” said Mrs. Washington, who held the door open for him.
“Just repurposing a little trash.” He winked at his co-teacher. As usual, she understood the method to his madness and winked back.
As his students filed in, they stared at the materials on the side table. “Yep,” he told them, “another STEM challenge.”
“Yay!” they shouted. The kids loved integrating science and engineering design.
Defining the Problem, Criteria, and Constraints
“In this hydroponics STEM activity, you will design a system that germinates basil seeds. As always, you’ll need to define the problem, as well as criteria and constraints.”
Mr. Grow walked up and down the aisles. As he walked, he gave each student a worksheet. “Let’s review. A criterion is something a solution must do, have, or be. But a constraint is a limitation. For example, in this challenge, you’ll have a limited amount of materials. Finish this worksheet. Then we’ll discuss it and get on with our engineering design project.”
After they’d finished discussing their responses, Mr. Grow distributed another set of pages. “First,” he said, “you’ll define the problem for this STEM challenge. Additionally, you’ll list criteria and constraints. Go ahead and work in your usual science groups. When you’ve finished that, you can begin your research.”
The kids wasted no time. Quickly, they broke into groups, pulled out their pencils, and began defining the problem.
Researching
Next, they pulled out their Chromebooks and began researching. After all, Mr. Grow had taught them that after the problem was defined, they should see what other people had come up with.
At the end of the period, Mr. Grow sent everyone back to their desks. “Tomorrow, we’ll continue with this project,” he said.
Brainstorming
The next day, Mr. Grow displayed a page on brainstorming. Before you go any farther with your hydroponics STEM activity,” he said, “we need to review some guidelines. Sometimes it’s easy to jump into a solution you saw online. But truly great engineers brainstorm first.
“Let’s review:
- Don’t judge.
- Encourage wild ideas.
- Piggyback on others’ ideas.
- Stay on topic.
- Take turns.
- Take notes.
Mr. Grow stepped back and let them get to work. As he walked around the room, he heard some crazy – but great – ideas.
Choosing the Best Solution and Building a Prototype
Once the groups finished brainstorming, they chose the best solution. Then they selected materials and set up their hydroponics systems.
At the end of the period, Mr. Grow looked over the set of prototypes. Yep, it looked like some real winners!
Continuing the Hydroponics STEM Activity
As time went by, kids realized that water was the key factor in success. In systems that received a moderate amount of water each day, seeds thrived. However, if a seed received too much water, it rotted. Furthermore, too little water made it dry up.
Identifying Failure Points
When systems failed, Mr. Grow encouraged them to identify the failure point and try again. By manipulating just one variable, kids could use a fair test.
Redesigning and Conducting a Fair Test
To Mr. Grow’s delight, the hydroponics STEM activity went on for months. Over time, he heard his students using more and more of the engineering design lingo. They really began to understand the process too:
- Identify failure points.
- Control the variables.
- Compare the outcomes.
- Measure.
- Replicate.
- Repeat.
Enjoy Teaching
As the kids’ basil plants grew taller, Mr. Grow reflected on the hydroponics STEM activity. First and foremost, his students had mastered the engineering design process. Second, they had explored an important life science concept – plants mainly need water, air, and light to grow. And, as an added bonus, he himself had been able to enjoy teaching a little more.