Real Science Teaching. Real Classroom Experience.
I’m Amy Brown, a veteran high school biology and chemistry teacher, wife, and mom who understands the daily reality of lesson planning, grading, meetings, and everything in between. I know what it feels like to have too much to do and not enough time to do it.
After decades in the classroom, I’ve created rigorous, classroom-tested biology and chemistry resources that save you planning time while still delivering strong, meaningful science instruction. Every lab, activity, and lesson is designed to move students beyond memorization and into real scientific thinking.
If you want your students excited about science and thinking deeply without spending your entire weekend planning, you’re in the right place.
“I just love getting kids hooked on science.”
Why do both plant and animal cells contain catalase?
Catalase is found in both plant and animal cells because all living cells produce hydrogen peroxide during normal metabolic processes. Catalase protects cells by breaking hydrogen peroxide down into water and oxygen.
Why is liver often used in catalase labs?
Liver cells contain large amounts of catalase because the liver plays a major role in detoxification. This makes liver an excellent tissue for demonstrating catalase enzyme activity in lab experiments.
Why do boiled tissues show little or no catalase activity?
Boiling denatures the catalase enzyme, changing its structure so it can no longer function properly. This prevents catalase from breaking down hydrogen peroxide.
What causes the bubbles in a catalase enzyme lab?
The bubbles are oxygen gas released when catalase breaks down hydrogen peroxide into water and oxygen. This visible reaction demonstrates enzyme activity.
The Affect of the Enzyme Amylase on Starch
Why Do Living Cells Need Buffers? A Homeostasis Lab for Biology
These enzyme labs and biology activities help students further explore enzyme function, enzyme activity, and biochemical reactions in living cells.
Enzyme Lab: The Effect of pH on Living Cells
Click the image to view Density Lab: Identifying Unknown Metals on TpT.
A density lab for high school chemistry or physical science gives students a hands-on way to connect mass, volume, and density. In this investigation, students use a balance and water displacement to determine the density of four unknown metals, then use a reference table to identify each sample. The lab also reinforces percent error calculations, graphing, and data analysis.
I like this lab because it brings several important science skills together in one manageable investigation. Students have a reason to measure carefully, their calculations help them solve a problem, and the follow-up questions ask them to think about what their numbers mean. It works well after students have learned how to calculate density.
Density is the ratio of mass to volume. Students may be comfortable substituting numbers into the equation, but working with unknown samples helps them understand why density is useful. A larger piece of a metal has more mass and occupies more volume than a smaller piece of the same metal, yet both have the same density under the same conditions.
Density = Mass ÷ Volume
For this lab, students receive four metal samples labeled A, B, C, and D. They measure the mass of each sample with a balance and determine its volume using water displacement. After calculating density, they compare their results with the values in the supplied reference table and choose the closest reasonable match.
This is also a useful opportunity to discuss density as a physical property. Students identify the samples without changing their chemical composition. The analysis questions ask them to consider other observable properties and whether density alone is always enough to identify an unknown substance. If your students need more practice with physical and chemical properties, my post about matter and change task cards offers another way to review those concepts.
Before students begin, review how to read the bottom of the meniscus at eye level and how to record measurements from the graduated cylinder. Students record the initial water volume, carefully lower a metal sample into the water, and record the final volume. The difference between those readings is the volume of the metal.
Volume of Metal = Final Water Volume − Initial Water Volume
Remind students to slide the sample gently into the cylinder, fully submerge it, and check for trapped air bubbles. A small error in the volume measurement can make a noticeable difference in the calculated density, especially when the sample displaces only a small amount of water. That gives you something concrete to discuss when students compare their experimental values with the reference table.
The lab includes percent error calculations, so students can evaluate how closely their measurements agree with the accepted densities. Use their results to discuss measurement precision and possible sources of error. For more ideas about preparing students to work successfully with lab equipment, see Taking Students to the Laboratory.
One of my favorite parts of this density lab is the graphing reinforcement. Graphing is a skill students need to practice throughout the year, and this activity connects the graph to the density concepts they have just used in the investigation.
The graphing section provides mass and volume data for five pieces of aluminum of different sizes. Students plot volume on the x-axis and mass on the y-axis. They must choose an appropriate scale, label the axes with units, give the graph a title, and plot the data carefully. The resulting pattern helps them see that mass and volume are directly proportional for a material with a fixed density.
Students then use their graph to determine the mass of an aluminum sample with a given volume and the volume of a sample with a given mass. One question asks them to predict a mass beyond the range of the supplied data, giving you an opportunity to discuss extrapolation. These questions require students to use the graph as a source of information.
If graphing is a skill you are working to strengthen in your classes, you may also enjoy Science Graphing Activities: Why Students Need to Learn Graphing by Hand. The density lab provides another opportunity to revisit those skills within your chemistry content.
The four-page handout includes space for calculations, written answers, and the graphing activity.
You can choose the metals that work best for your classroom and available supplies. I most often use copper, aluminum, lead, and zinc. Choose samples that fit safely inside your graduated cylinders and have densities represented in the reference table. Label them with letters so students use their measurements to determine their identities.
The teacher guide includes ordering information for metal strips, along with preparation instructions and suggestions for setting up the investigation.
If you use rectangular metal strips, their volume can also be calculated from their dimensions. Students measure the length and width with a metric ruler and use the strip’s thickness as the third dimension. Because thin strips can be difficult to measure accurately with a ruler, use the thickness listed on the package.
Volume = Length × Width × Thickness
Be sure students convert all three measurements to the same unit before multiplying. Measurements in centimeters give a volume in cubic centimeters, and 1 cm3 is equivalent to 1 mL. Comparing this result with the water displacement measurement can lead to a useful discussion about the strengths and limitations of each method.
The lab includes two versions of the student handout with the same investigation and questions. The four-page version provides space for students to record data, show calculations, write answers, and construct their graph. The two-page paper-saving version allows students to complete their work on their own notebook paper and graph paper, so you can reuse the directions with another class.
Both versions are editable, allowing you to adjust the directions or questions for your students. The teacher guide includes preparation and setup instructions, materials ordering information, tips, sample data, and detailed responses to the questions.
This lab is included in my Chemistry Math Unit: Scientific Measurements, Calculations, and Graphing. It gives students an opportunity to apply measurement, calculations, and graphing in a hands-on investigation. If you already own that unit, you already have this lab.
For ideas about building those skills in your chemistry classes, visit my post on chemistry measurement and math skills. You can also explore The Ultimate Guide to Teaching Science Process Skills for ways to reinforce measurement, data analysis, and scientific thinking throughout the year.
If you only need the individual investigation, Density Lab: Identifying Unknown Metals is available separately on TpT. Click the link or any image in this post to view the resource and its preview.
If you are looking for Valentine’s Day biology activities that are actually meaningful for high school students, you are not alone. Finding engaging, age appropriate science activities that still connect to your curriculum can feel like a challenge. The good news is that you can bring a little seasonal fun into your classroom without sacrificing rigor.
Here are a few of my favorite Valentine’s Day science activities that work well in high school biology and chemistry classes.
For me, it just so happens that I usually manage to be teaching the circulatory system around Valentine’s Day. Although not nearly as fun as exchanging valentines and getting treat bags, at least it does involve the heart.
One of my favorite labs is Measuring the Heart Rate in Daphnia. It is a two part activity. In the first part, students explore the effect of temperature on heart rate. In the second part, students design their own experiment to test a different variable and see how it affects heart rate. It is a really fun lab, and students love it.
If you want the full lab setup, procedure, and more teaching details, you can read more here: Measuring Heart Rate in Daphnia
Granted, the Daphnia lab takes some planning and probably takes two class periods to complete. If you are looking for something quick and very easy, take a look at my Science of Valentine’s Day video from my YouTube channel, the Amy Brown Science Learning Lab. The four minute video is free for your classroom use.
I also wrote a fun acrostic puzzle activity to accompany the video. Students answer questions to decipher three really corny Valentine jokes. You can view the puzzles here: The Science of Valentine’s Day
Finally, for chemistry teachers, I have a Valentine’s Day Color by Number activity with a Valentine theme. Students practice writing chemical formulas and naming compounds while uncovering the hidden picture.
This one works especially well as a quick review activity, an easy day lesson, or a simple option during a busy week. You can view it here: Chemistry Valentine’s Day Color by Number
This Daphnia lab also fits well into other units beyond the circulatory system. You can use it when discussing ecology, experimental design, or data analysis.
If you are teaching ecology, you might also like to read about this activity: Population Ecology Lab
What are good Valentine’s Day biology activities for high school?
Labs like the Daphnia heart rate experiment, short science videos with guided questions, and review activities all work well while keeping the focus on content.
Can you do labs on Valentine’s Day?
Yes. As long as the activity connects to your standards, it can be a great way to keep students engaged during a high energy day.
What is a quick Valentine’s Day science activity?
Short videos, bell ringers, or simple review activities like puzzles or color by number are easy to implement with very little prep.
Watch Their Hearts Beat: A Daphnia Lab That Brings Biology to Life
If you’re looking for a biology lab that’s easy to set up, actually engages students, and still hits real science skills, this Daphnia heart rate lab is one of my favorites. Students observe the beating heart of a live Daphnia under the microscope, test the effect of temperature on heart rate, and then extend the investigation by designing their own experiment. It is the kind of lab that feels exciting for students while still building serious biology skills.
Daphnia are tiny aquatic crustaceans, sometimes called water fleas. Their transparent exoskeleton makes the beating heart visible under low power, which makes them ideal for a lab on physiology, environmental effects on organisms, graphing, and experimental design. This lab gives students the rare chance to work with a living organism and collect real data in a way that is visual, concrete, and highly engaging.
This lab is also classroom friendly. It is low prep, easy to implement, and flexible enough to use with standard biology, honors biology, and AP Biology students. If you want a ready to use resource with student handouts, graphing pages, extension activities, and teacher guidance, you can find it here: Measuring Heart Rate in Daphnia Lab.
In this lab, students observe the beating heart of Daphnia and investigate how temperature affects heart rate. Because Daphnia are ectotherms, their body temperature changes with the surrounding environment, which makes temperature an excellent variable for students to study. As students compare conditions, they can see physiology in action instead of only reading about it in a textbook.
This first part of the lab gives students a structured, guided investigation. They collect data, graph their results, and answer analysis questions. The experience helps students connect temperature, metabolism, and organismal function while practicing core science skills in a meaningful context.
One of the biggest challenges in a Daphnia heart rate lab is helping students find the heart. The digestive system of Daphnia is active, and students often mistake that movement for the heartbeat. The heart is located just behind the head on the dorsal surface of the body, and it appears as a very small, clear, transparent beating sac.
That is one reason this resource includes a diagram for each lab station. Having a visual reference makes a big difference and helps students begin the lab with more confidence. It also reduces frustration and saves class time because students are more likely to focus on the correct structure from the start.
If you teach body systems, you might also like this related post on the circulatory system interactive notebook.
This resource actually includes three different activities, which makes it much more than a simple one day microscope lab.
First, students follow the lab procedure to determine how temperature affects the heart rate of Daphnia. This is the structured part of the lab and works well for a wide range of learners.
Second, students can design their own experiment to test the effect of a new variable on Daphnia heart rate. This is where the lab becomes especially valuable because students move beyond following directions and begin thinking like scientists.
Third, honors and AP Biology students can complete the Q10 Temperature Coefficient worksheet for a deeper quantitative extension.
This structure gives you flexibility. You can stop after the guided temperature lab, or you can extend the activity into a more advanced investigation. That makes it easy to adapt for your schedule, your students, and the level of rigor you want.
One of the strongest parts of this Daphnia lab is the student designed experiment. After students complete the guided temperature investigation, they can use the scientific method to design an experiment that tests the effect of a different variable on heart rate. In my classroom, this is where the fun really begins.
Students state a hypothesis, identify control and experimental groups, carry out the procedure, collect data, graph their results, and write a conclusion based on the evidence. This part of the lab takes more time, but it also leads to some of the best learning. Students quickly discover that real experimentation requires careful planning, revision, and problem solving.
If you are nervous about student designed experiments, do not be. With guidance on the front end, students often surprise you with their creativity and persistence. This part of the lab is excellent for reinforcing experimental design in a way that feels authentic rather than forced.
This lab also includes a Q10 Temperature Coefficient worksheet, which makes it especially useful for honors and AP Biology classes. Students can move beyond simple observation and graphing into a more advanced analysis of how temperature affects biological processes.
That means this resource is not limited to one level of biology. The first activity is accessible enough for many high school students, while the later extensions provide the rigor needed for advanced learners.
Students assemble a simple habitat chamber using depression slides, a pipet, and other basic materials. They observe the beating heart under the microscope, compare the effect of different temperatures, record heart rate data, and graph their results. From there, you can extend into a student designed investigation and formal lab report if you choose.
This is the kind of lab that keeps students interested because they are working with a living organism and collecting real data. It also gives you a natural opportunity to teach careful observation, ethical treatment of organisms, graphing, analysis, and experimental design all within one lab sequence.
Please note: Teach students to respect all living organisms. No harm should come to the Daphnia during this experiment.
This lab is a favorite of mine every year because it combines genuine student excitement with meaningful biology content. Students love looking at living organisms under the microscope, and Daphnia are especially fascinating because the beating heart is visible. At the same time, the lab goes far beyond novelty.
This investigation helps students practice:
It also supports the kind of hands on biology experience that teachers want in the classroom. Working with living organisms helps students build curiosity, observation skills, and appreciation for the living world.
When the lab is over, my Daphnia spend the rest of their days in my Elodea tank.
This Daphnia heart rate lab includes everything you need for successful implementation:
That combination makes this much more than a simple worksheet or one day activity. It is a complete lab sequence that can be adapted to the needs of your classroom.
If you are looking for a complete, ready to use Daphnia heart rate lab that saves prep time and gives students a meaningful biology experience, this resource is a great fit. It combines microscope work, physiology, graphing, scientific method, and optional advanced extensions in one engaging package.
Click here to view the resource: Measuring Heart Rate in Daphnia Lab
