Grade 8 Units

Natural Selection and Common Ancestry

At the beginning of this unit, students hear about the surprising fossil of an ancient penguin (nicknamed “Pedro”) in a podcast from the researchers who found and identified the fossil. Students analyze data about modern penguins and Pedro to develop initial explanations for how modern and ancient penguins could be connected. 

After looking at penguins to introduce the phenomenon and how scientists look at data, students analyze data from ancient and modern species of horses, whales, and horseshoe crabs to see whether the data for these organisms have similar patterns. Then, to figure out the cause of the changes they have observed in populations, students explore more recent and rapid cases of changing heritable trait distribution in bird, fish, plant, and bacteria populations and explain them by developing a model for natural selection.  In the last part of the unit, students use their model for natural selection to return to their original questions, and explain how some body structure variations in different species of modern penguins could result from natural selection and how they could descend from a common ancient ancestor penguin population.

Chemical Reactions and Matter

Students' conceptual understanding of chemical reactions for middle school science is foundational to much science learning. Understanding atomic level reactions is crucial for learning physical, life, earth, and space science. Even more importantly, they open up new windows of curiosity for students to see the world around them. By eighth grade, students are ready to take on the abstract nature of the interactions of atoms and molecules far too small to see. 

To pique students’ curiosity and anchor the learning for the unit in the visible and concrete, students start with an experience of observing and analyzing a bath bomb as it fizzes and eventually disappears in the water. Their observations and questions about what is going on drive learning that digs into a series of related phenomena as students improve their models depicting what happens during chemical reactions. By the end of the unit, students have a firm grasp on how to model simple molecules, know what to look for to determine if chemical reactions have occurred, and apply their knowledge to chemical reactions to show how mass is conserved when atoms are rearranged.

Chemical Reactions and Energy

In this unit, students are introduced to the anchoring phenomenon—a flameless heater in a Meal, Ready-to-Eat (MRE) that provides hot food to people by just adding water. In the first lesson set, students explore the inside of an MRE flameless heater, then do investigations to collect evidence to support the idea that this heater and another type of flameless heater (a single-use hand warmer) are undergoing chemical reactions as they get warm. Students have an opportunity to reflect on the engineering design process, defining stakeholders, and refining the criteria and constraints to design their own flameless heater.

Students learn about exothermic and endothermic chemical reactions, and develop design solutions by investigating how much food and reactants they should include in their homemade heater designs.  They go through a iterative design cycle, including steps that involve testing, peer feedback, consideration of design modification consequences, analysis of impacts on stakeholders, and redesign. Finally, students optimize their designs and have another team test their homemade heater instructions.

Metabolic Reactions

This unit on metabolic reactions in the human body starts out with students exploring a real case study of a middle-school girl named M’Kenna, who reported some alarming symptoms to her doctor. Her symptoms included an inability to concentrate, headaches, stomach issues when she eats, and a lack of energy for everyday activities and sports that she used to play regularly. She also reported noticeable weight loss over the past few months, in spite of consuming what appeared to be a healthy diet. Her case sparks questions and ideas for investigations around trying to figure out which pathways and processes in M’Kenna’s body might be functioning differently than a healthy system and why.

Students investigate data specific to M’Kenna’s case in the form of doctor’s notes, endoscopy images and reports, growth charts, and micrographs. They also draw from their results from laboratory experiments on the chemical changes involving the processing of food and from digital interactives to explore how food is transported, transformed, stored, and used across different body systems in all people. Through this work of figuring out what is causing M’Kenna’s symptoms, the class discovers what happens to the food we eat after it enters our bodies and how M’Kenna’s different symptoms are connected.

Matter Cycling and Photosynthesis (taught starting in 2026-27)

This unit on the cycling of matter and photosynthesis begins with students reflecting on what they ate for breakfast. Students are prompted to consider where their food comes from and consider which breakfast items might be from plants. Then students taste a common breakfast food, maple syrup, and see that according to the label, it is 100% from a tree.

Based on the preceding unit, students argue that they know what happens to the sugar in syrup when they consume it. It is absorbed into the circulatory system and transported to cells in their body to be used for fuel. Students explore what else is in food and discover that food from plants, like bananas, peanut butter, beans, avocado, and almonds, not only have sugars but proteins and fats as well. This discovery leads them to wonder how plants are getting these food molecules and where a plant’s food comes from.

Students figure out that they can trace all food back to plants, including processed and synthetic food. They obtain and communicate information to explain how matter gets from living things that have died back into the system through processes done by decomposers. Students finally explain that the pieces of their food are constantly recycled between living and nonliving parts of a system.

Earth's Resources and Human Impact

This unit begins with students observing news stories and headlines of drought and flood events across the United States. Students figure out that these drought and flood events are not normal and that both kinds of events seem to be related to rising temperatures. This prompts them to develop an initial model to explain how rising temperatures could cause both droughts and floods and leads students to wonder what could cause rising temperatures, too. This initial work sets students up to ask questions related to the query: How do changes in Earth’s system impact our communities and what can we do about it?

Students spend the first lesson set gathering evidence for how a change in temperature affects evaporation, precipitation, and other parts of Earth’s water system. They use evidence to support a scientific explanation that two climate variables (temperature and precipitation) are changing precipitation patterns in the case sites they investigated. Students figure out from data that the rising temperatures are caused by an imbalance in Earth’s carbon system, resulting in a variety of problems in different communities. The unit ends with students evaluating different kinds of solutions to these problems and how they are implemented in communities through strategic planning.