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.

New FREE Item: Chart of Amino Acids and Codons

If you are a biology or life science teacher, I believe that you will be able to use this!

As you know, there are 20 amino acids that are used to build all the various proteins in living systems.  When teaching about protein synthesis, I like to have my students work out this process.  I give them the DNA sequence of a particular gene, and ask them to determine the mRNA sequence, the tRNA sequence, and the amino acid sequence of the protein.  In order to determine the amino acid sequence, the students need a chart in order to look up the mRNA codons.

I have used this chart for some time and I like it best of all the ones I have used.

Here is a link to this FREE product:  Chart of Codons and Amino Acids.  I hope that you find this "freebie" useful.

Also related:  Determining the Traits of a Mystery Organism Organism Through Protein Synthesis.

Science Skills: Comparing and Contrasting

I am back on my "science skills" kick!!  

I spent most of my summer refining the ways that I teach the important skills in science:  critical thinking, problem solving, graphing, metric measurements, the scientific method, etc.  In this technological age, teaching science has become much less about the "facts" and much more about the "skills".  The facts are at our fingertips....we only have to push a few buttons on our computer and the facts coming flying out at us.  Don't misunderstand, though.  I still teach a fairly traditional biology class and I make sure I cover what needs to be covered.

So what has changed in my class?  I am making much more of an effort to included activities, worksheets, and labs that are not as much "content based" as they are "skills based".  The science portion of the ACT test is now called "Science Reasoning".  The AP Biology curriculum is being changed next year in favor of an inquiry approach to biology.  These changes are good.  The message to science teachers is "Teach your students how to THINK!"

Most science teachers would agree that students who have developed good "science skills" will be far more successful in a science class than those students who simply memorize a laundry list of science facts.   In my attempt to include more problem solving activities, I wrote this lesson (see link below) and just tried it out in my Biology I classes today.  It was a lesson (or a review) in "comparing and contrasting" for the science student.

I began the lesson with a short PowerPoint presentation.  I wanted my students to understand what it means to "compare and contrast".  During the Powerpoint presentation, students were asked to compare two living organisms.  The students made a list of the similarities and differences between these two organisms.  After comparing and contrasting the two organisms, I had the students determine why these similarities and differences are important to these organisms.

The PowerPoint presentation was followed up by 5 page student worksheet.  This worksheet made the students practice over and over the skills of comparing and contrasting.  The questions were thought provoking and required problem solving and critical thinking skills.

This lesson can be used at different times of the year.  Next year, I plan to use it at the beginning of the school year to get my students "thinking like a scientist".  Today, I used this Powerpoint and worksheet to introduce a unit on classification and taxonomy.  This lesson would also work extremely well when teaching a unit on Evolution.

I think this approach to teaching science will really pay off for my students as they take the ACT and AP exams.  As they were moaning and groaning over today's assignment, I reminded them, "No pain, no gain!!"

Here is a link to the product, if you are interested.

Science Skills Worksheet and PowerPoint:  Comparing and Contrasting

The Best Osmosis and Diffusion Lab for High School Biology

The Best Osmosis and Diffusion Lab for High School Biology: Engaging, Visual, and Data-Driven

Looking for the perfect biology lab to teach osmosis and diffusion?
This hands-on lab activity combines visual learning with measurable results. And, best of all, it’s easy to set up, uses common lab materials, and reinforces essential biology concepts like plasmolysis, hypotonic vs. hypertonic solutions, active vs. passive transport, and water movement across cell membranes. The first part of the experiment involves observing plasmolysis in cells. The second part of the lab is a potato osmosis lab. It is a classic hands-on experiment that helps students investigate diffusion and osmosis by measuring mass changes in potato cores placed in solutions of varying solute concentrations.

✅ Minimal prep

✅ Simple materials

✅ Microscopy, graphing, and calculations—all in one lab!

Why Every Biology Teacher Needs This Osmosis and Diffusion Lab:

When it comes to teaching cell transport processes like osmosis, diffusion, and plasmolysis, it’s critical to move beyond definitions and diagrams. Students need to see it. They need to measure it. They need to analyze it.

That’s why this osmosis and diffusion lab activity has become a staple in my high school biology classroom. It checks every box:

• Reinforces microscope skills
• Visualizes plasmolysis in plant cells
• Engages students in weighing, measuring, and calculating
• Requires a hand-drawn graph
• Promotes data analysis and critical thinking
• Illustrates real-world application of scientific method

A Timeless Biology Lab That Just Works

Osmosis and diffusion are cornerstones of any cell structure and function unit. While there are many labs available on this topic, this one stands out. I’ve used countless variations over the years, and this two-part lab consistently generates the strongest student engagement and understanding.

When students literally say, “Whoa, that’s so cool!” as they watch plasmolysis unfold under the microscope—that’s a teaching win.

Part A: Observing Plasmolysis in Real Time (Qualitative)

In the first part of the lab, students observe osmosis in plant cells using a microscope. Start with a thin layer of red onion skin or a leaf from an Elodea (Anacharis) plant. Students first examine the cells in distilled water, sketch the cells, and note the position of the cytoplasm and vacuole.

Next comes the wow moment: swap the distilled water for a 15% salt solution. The plasmolysis is immediate and dramatic. Students watch as the cell membrane pulls away from the cell wall due to water loss. It’s the perfect visual demonstration of hypertonic solutions in action.

Part B: Measuring Osmosis in Potato Cores (Quantitative)

The second half of the lab brings in data analysis and graphing practice—making it ideal for reinforcing both science content and scientific skills.

Here’s how it works:

1.     Use a cork borer to create uniform potato cores. If you are in a rush, just cut up the potatoes into small cubes. It still works great!

2.     Mass the cores in groups of four and record the initial weight.

3.     Place each group in a different sucrose solution of known molarity.

4.     Let them sit overnight.

5.     Re-mass the cores the next day and calculate the percent change in mass.

6.     Plot the data to determine the solute concentration of the potato tissue.

7.     Analyze whether each solution was hypotonic, hypertonic, or isotonic.

How Long Should Potatoes Sit in Solution During this Osmosis Lab?

In order to get the best results, cover the small beakers with aluminum foil and allow them to sit overnight. Since this lab takes a little time to set up, it is unlikely that measurable results can be obtained by the end of the class period. 

Potato Osmosis Lab FAQ's

What is the best potato variety for an osmosis experiment?

Russet potatoes are commonly used for osmosis experiments because they are large, firm, and easy to core consistently. Their high starch content and uniform texture make changes in mass easier to measure. That said, other potato varieties can work as long as all samples come from the same potato or variety to keep results consistent.

How long should potato cores incubate in solution during an osmosis lab?
Longer incubation times will produce more noticeable mass changes. The best measurable results will occur if the potatoes are allowed to soak overnight in their various solutions. The key is keeping incubation time consistent for all samples so results can be accurately compared.

What is a cork borer and why is it used in a potato osmosis lab?
A cork borer is a cylindrical tool used to cut uniform cores from materials like potatoes. Using a cork borer helps ensure that all potato samples have the same diameter, which improves the reliability of mass and length measurements. If a cork borer is not available, careful cutting with a knife can work, but results may be more variable.

Is this considered an osmosis lab or a diffusion lab?
This experiment primarily demonstrates osmosis, which is the movement of water across a semipermeable membrane. While diffusion is a related concept, the mass changes observed in potato cores are due to water moving into or out of potato cells in response to solute concentration. For this reason, it is best described as a potato osmosis lab that supports understanding of both diffusion and osmosis.

The beauty of this activity? It reinforces the concepts of osmotic pressure, solute concentration, and equilibrium, all while helping students master graphing and data interpretation.

Looking for a ready-to-use resource that includes  student instructions, answer keys, and editable versions? Check out my Osmosis and Diffusion Lab on Teachers Pay Teachers! It's classroom-tested, student-approved, and designed to make your job easier.

What's In a Name - A Study of Biological Prefixes and Suffixes

Want your students to succeed in your biology class?  Start by having them learn these prefixes and suffixes!

The new vocabulary words in a first year life science or biology class can be overwhelming.  However, many of the vocabulary words contain either a prefix or a suffix that will help the student understand the meaning of the word.  This assignment will help to familiarize your students with many of the common prefixes and suffixes used in biology.  This may seem difficult at first, but once the student learns these prefixes and suffixes, it will be of great benefit to them as the year progresses.

This document contains two separate products:
1.  What's In A Name Activity Wroksheet
2.  Quiz on Biological Prefixes and Suffixes

The "What's In a Name" activity is a four page worksheet with answer key for the teacher.  The student will learn 50 prefixes and 30 suffixes that are commonly found in many biological terms.  There are 44 problems on this worksheet.

For example:  What does the term "polysaccharide" mean?
Answer:  "Poly" means "many" and "sacchar" means "sugar".  Therefore a polysaccharide is a compound composed of many sugars.

Other problem examples:  What term means "a study of small forms of life"?
Answer:  "Micro" means "small".  "Bio:" means "life".  "Logy" means "a study of".  The term that means "a study of small forms of life" is "microbiology".

There are sufficient practice problems to help the student begin to master these prefixes and suffixes.

Also included is a short quiz.  I require my students to memorize these prefixes and suffixes.  To check to see if they are studying, I use this short quiz.  There are 50 questions/problems on this quiz.  It, too, comes with an answer key.

This is one of the science skills that I stress from the beginning of the year until the end.  You will not regret teaching your students how to break words apart to decipher their meaning.

What's In a Name?

Practice Problem Worksheet and Quiz

Measurement Madness! (Reinforcement for Metric Ruler and Metric Conversions)

Measurement Madness!

(Reinforcement Using a Metric Ruler and Completing Metric Conversions)

Last week, two things happened that were the inspiration for this new product:  (1) I had to be absent and knew that I would have a sub in my room.  I needed a good assignment to leave for my students to complete in my absence, and (2) I was shocked to discover that some of my HIGH SCHOOL students still had difficulty using a metric ruler properly and converting from one unit to another.

The worksheet begins.....

Students make observations about their ruler.
Students must draw lines of a give length.
Students must measure the lines that are already drawn on the worksheet.

Page 2.....

Students use a ruler to measure the sides of a 2-dimensional object.

Students determine the area of the figure in both centimeters and millimeters.

Page 3....

Students us a ruler to measure the sides of a 3-dimensional object.

Students determine the volume of the figure in both centimeters and millimeters.

Students complete practice problems on converting from one metric unit to another metric unit using the process of dimensional analysis.

Page 4 .....

I want my students to understand how important the metric system is to their lives and to realize that the metric system is much easier to use than our archaic English system of measurement.

I wrote a few paragraphs about really cool animal facts.  Each paragraph contains statistics about the animal that have to be converted to another system of measurement.  If the stats are in feet, the student will convert them to centimeters, and vice-versa.  My kids LOVED the pictures I included.

Page 5......

This page contains more animal fact/conversion paragraphs, as well as a few follow up questions.

This product also comes with a 3 page answer key.

This is suitable for grades 7 - 10.  I feel like it went a long way in reinforcing some critical science and math skills.  

Happy Teaching!!

Measurement Madness!

New FREE Item: "Using a Graph to Find Area"

I recently realized that my students need a lot more extra practice on certain science skills:  Graphing, use of simple pieces of lab equipment, problem solving, critical thinking, interpolation and extrapolation.  I wrote this activity to cover all of these things.  

FREE download:

Using a Graph to Find Area

In this lab activity, I give each group of students 4 pieces of poster board of regular size.  Prior to the lab, I cut the poster board into different sizes and shapes.  The students use a ruler to determine the length and width of each regular-shaped piece.  They then determine the area of the piece of poster board.

A balance is used to determine the mass of each piece of poster board, and this data is placed on a graph.  The student should immediately see from the graph that there is a direct relationship between mass of the poster board and the area of the poster board.  When the four points are plotted on the graph, it should result in a straight line.

There is nothing amazing about this activity, but it does provide VALUABLE practice in graphing.  Next, comes the problem solving and critical thinking section of this lab.  Students are given a piece of poster board that is irregular in shape, and they are asked to determine the area of this oddly shaped piece of poster board.  The student easily determines the mass of the irregular piece.  Once the mass is known, the student will use their graph to determine the area.


The activity also includes follow up questions.  The student will use their graph to interpolate and extrapolate to determine the answer to a series of questions.


I am offering this activity to you for free.  I hope that you will enjoy using it with your students.

Happy Teaching!