Student Designed Experiment Lab for Teaching Experimental Design in Middle and High School

Student Designed Experiment Lab for Teaching Experimental Design

Many upper middle school and high school students can list the steps of the scientific method. Far fewer can design a controlled experiment independently in a secondary science classroom.

After years of teaching high school biology, I realized that although my students could recite the steps, they struggled to apply them. Like many science teachers, I had relied on cookbook labs where students followed directions and reached an expected conclusion. But that approach does not truly build experimental design skills.

If we want students to understand experimental design, we must give them structured opportunities to design and carry out their own controlled investigations.

This student designed experiment lab has worked extremely well for me when teaching experimental design in secondary science. This investigation is designed specifically for middle school and high school science courses and is not intended as a take home science fair project.

If you would like ready to use handouts for this lab, you can find them here:
Scientific Method Lab: The Student Designed Experiment

Why Student Designed Experiments Matter in Secondary Science

When students design a controlled experiment themselves, they move beyond memorization and begin applying the scientific method in a meaningful way.

They must:

• Identify independent and dependent variables

• Define control and experimental groups

• Recognize constants

• Design a data table

• Graph results

• Analyze experimental data

• Draw evidence-based conclusions

These are foundational scientific thinking skills that students need in middle school, high school, and beyond.

Teaching experimental design does take time. It requires modeling, feedback, and revision. But the depth of understanding students gain is well worth the effort.

If you are looking for additional strategies for teaching experimental design, you may also find my post on how to teach students to design experiments helpful, where I share practical scaffolding techniques and classroom examples.

How This Student Designed Experiment Lab Works

When I first introduce student designed experiments, I keep the topic simple and the materials limited. This prevents students from getting overwhelmed by content and allows them to focus on learning how to design a controlled experiment.

In this lab, students design an experiment to test how different quantities of water affect radish seed germination.

The topic is intentionally straightforward. I do not want students getting bogged down in advanced biology concepts. I want them concentrating on experimental design.

All students work on the same investigation using the same simple materials. This keeps the class moving in the same direction and allows me to provide targeted guidance. Especially in larger classes, this structure makes inquiry based learning manageable.

If your students need additional support identifying variables and control groups, you may also find my Scientific Method PowerPoint lesson helpful.

Materials for the Controlled Experiment

This lab requires only simple materials:

• Petri dishes or similar containers

• Radish seeds

• Graduated cylinder

• Water

Because the materials are basic and inexpensive, this experimental design lab is realistic for most secondary science classrooms.

What Students Must Include in Their Experimental Design

Before beginning the lab, students must submit their experimental design for approval. This step is essential. It allows for feedback and refinement before they begin collecting data.

Each student must clearly define:

• A testable hypothesis

• The independent variable

• The dependent variable

• The control group

• The experimental groups

• The constants

• A detailed procedure

• A properly structured data table

After collecting data over several days, students must:

• Graph their results

• Analyze patterns in the data

• Form a conclusion supported by evidence

This structured process helps students understand how to design a controlled experiment from start to finish.

Managing a Student Designed Experiment in a 50 Minute Class Period

This lab cannot be completed in a single class period. I require students to:

1. Submit their design for approval

2. Revise based on feedback

3. Carry out the investigation

4. Return at intervals to count germinated seeds

5. Analyze and graph data

6. Submit a final lab report

Yes, it is time consuming. But when students complete this process, they truly understand how the scientific method works in practice.

The goal is not speed. The goal is deep understanding.

Extending the Investigation

If time allows, students can design a second experiment testing a different variable, such as:

• The effect of temperature on seed germination

• The effect of pH on seed germination

By this point, students are much more confident in designing controlled experiments independently.

Ready to Teach Experimental Design with Confidence?

If you are looking for structured handouts that guide students through designing a controlled experiment, this resource includes two sets of lab materials:

• A complete seed germination student designed experiment

• A reusable experimental design packet that can be used all year

You can find it here:
Scientific Method Lab: The Student Designed Experiment

Teaching experimental design requires patience, structure, and feedback. But when students design and carry out their own investigation, they gain a concrete and lasting understanding of scientific thinking.

And that makes it worth every minute.