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Blog / 4 Activities for Teaching Photosynthesis in High School Biology
Blog post banner image with a teacher in a yellow shirt and glasses holding a potted plant, and writing on the left that reads, "4 Activities for Teaching Photosynthesis in Biology."

4 Activities for Teaching Photosynthesis in High School Biology

It only takes one word to get high school biology students shaking in their boots: photosynthesis. 

High school students think photosynthesis is one of the most difficult ideas to understand. 

Can you really blame them?

Photosynthesis is an abstract concept, and it can be difficult to visualize the chemical reactions that are taking place at the cellular level. There is also just so much information, such as the different inputs and outputs of the light and dark reactions. 

What if I told you it didn’t have to be this way? 

There are so many activities to help teach photosynthesis to your high school students that they don’t have to feel completely lost. 

Let’s explore my top four photosynthesis activities that have been tried and tested in the classroom to bring you and your students the results you want!

A photo showing the green leaves of a tree.

Algae Bead Photosynthesis Lab

The Algae Bead Photosynthesis Lab is a newer lab activity that has become popular in biology classrooms. The students love it! 

Disclaimer: You have to buy algae beads or a lab kit to do this experiment, but it is totally worth it!  

In this lab, students will look at how the amount of oxygen in the algae beads changes. The concentration of oxygen will be proportional to the amount of light that the beads are exposed to. 

Students will collect data for four days. 

Based on how much oxygen is in the beads, students should be able to build a model of photosynthesis. The algae beads will have a change in density, which causes them to float in the solution. 

Want to take it a step further? 

For my advanced students, I extended the activity to include an inquiry activity. For this activity, the students were told to see what happened to the algae beads when they used different sunscreens. 

Talk about engaging and relatable for the students!

An image showing a laboratory area. In the laboratory area, there are various green plants in petri dishes.

Testing for Starch in Leaves

While I love the algae bead lab, it does require some extra materials and prep work. An alternative lab demonstrating photosynthesis tests leaves for starch, which requires common laboratory supplies. 

In this lab, students are using boiling water and ethanol to extract the chlorophyll from the cells. Iodine is then used to test the leaves for the presence of starch. By testing for starch, students can determine if photosynthesis occurred. 

I love using this lab activity because it is a very visual experiment, which students tend to prefer. My students are always amazed at how the leaf color changes!

A graphic showing two leaves - the first is green and in between them is an iodine bottle and an arrow, and the second leaf is blue-black color.

Virtual Photosynthesis Labs

We all know that physical, hands-on labs are the best learning tools for high school students, but…

Let’s face it…

We all know there are times we don’t get to certain labs. You could miss class time due to weather closures. You could miss class time due to illness. There are so many reasons that you may not get to a lab. 

Luckily, we have technology! (*insert bell sound here*) 

The next best alternative to a real lab is a virtual lab. There are so many free virtual laboratory activities that simulate what happens in the real lab. 

One of my favorite virtual photosynthesis labs is the Rate of Photosynthesis Lab

In this virtual experience, students can change how much light and how hot it is to see what happens to a plant. Students will measure the rate of photosynthesis based on the number of oxygen bubbles given off per minute.

There is also a lovely virtual lab that tests the effect of different wavelengths of light on plant growth. It has a virtual ruler to measure growth, and has an interactive table to input results.

An image of a virtual photosynthesis lab on a computer screen. The screen shows a lamp shining light into a container of water with a plant and thermometer. On this screen, it shows that you can adjust the lamp's intensity and temperature. The number of bubbles is also on the screen.

Photosynthesis Reactions Doodle Notes

Lastly (but certainly not least), I love using Doodle Notes to teach photosynthesis. If you’ve read my post on ways to use Doodle Notes in your classroom, you already know my love for these runs deep. 

Check out my Photosynthesis Doodle Notes here! 

Doodle Notes are a great activity for photosynthesis because they help summarize a very complex process using clear diagrams. My Doodle Notes go into more detail about how the light-dependent and light-independent reactions work so that students can understand them better.

A close up of a completed set of Doodle Notes showing the light-dependent reactions of photosynthesis.

How have I used Doodle Notes in my photosynthesis unit?

I have used Doodle Notes in multiple ways, depending on how the year is going. The main three ways I use Doodle Notes in my classroom are

  1. A review activity
  2. Whole-group notes
  3. A homework activity

Regardless of how Doodle Notes are used, students will be more engaged and will find photosynthesis not as challenging as they thought! 

A close up of a completed set of Doodle Notes showing the photosynthesis reactions and a doodle of the chloroplast where the reactions take place.

I hope you found these four ways to teach photosynthesis helpful! The main goal of these activities is to get the students interested and help them break down the idea of photosynthesis so they can understand it better. 

Remember to check out my Photosynthesis Doodle Notes for your classroom! 

I hope you have a wonderful day,

Emma The Teachie

P.S. If you are also teaching Cellular Respiration, then check out my blog post on how to teach cellular respiration!