Introduction

After a holiday meal, we’re often left with more than full stomachs — there are food scraps, packaging, and leftovers that need to be managed. What happens to all of that waste? Does it simply disappear into the trash bin, or could its energy be recovered to become something useful?

In this activity, you’ll explore how the things we throw away after a holiday meal can become sources of energy and resources instead of just garbage. You’ll sort different meal items into Energy Pathway Bins, analyze how much energy can be recovered or saved, and reflect on how small choices connect to bigger systems that recover and conserve energy.

Step 1: Review the Four Energy Pathways

Energy Pathway BinDescription
Compost/Biogas (organic waste)Organic materials can break down naturally into nutrient-rich compost or be processed in special systems (anaerobic digesters) that produce methane gas for heat or electricity.
Recycling (uncontaminated paper, metal, glass, plastic)Clean packaging can be reprocessed into new materials, saving large amounts of manufacturing energy.
Food Donation (unopened shelf-stable food)Unopened, shelf-stable foods can be donated to prevent food waste and support the community.
Landfill (non-recyclable waste)Non-recyclable, contaminated, or synthetic materials end up here, where most of their energy potential is lost.

Step 2: Sort the Meal Item Cards

Step 3: Quantitative Reasoning: Energy and Recovery

Every material and food item contains embedded energy — the energy it took to make, transport, and process it. When materials are recovered (through recycling, composting, or biogas), part of that energy can be saved or regained.
You’ll use simple estimates to explore how much energy or emissions can be saved through different waste-handling choices.

Reference Data Table

ItemEmbedded Energy*(MJ/kg)Recovery Potential
Aluminum~372HighRecycling saves ~90-95% of that energy
PET Plastic~60Medium~75% recovered if recycled
Paper~50MediumSaves ~40-70% of the energy
Glass~120Low~30% recovered energy
Food waste~7-8LowEnergy recovery is possible but limited

Estimation Questions
Show your reasoning with both numbers and words. Use the data in the table below to estimate and compare. 

  1. Which item in the table requires the most energy to produce, and which requires the least? What does this suggest about which materials are most important to recycle? 




  2. If recycling saves about 95% of the embedded energy for aluminum, about how much energy is recovered per kilogram recycled? Explain your reasoning. 




  1. Even though each plastic bottle recycled saves more energy per kilogram, paper is recycled much more often and in larger quantities. What do you think are some reasons for this? How would you decide which materials should be prioritized for recycling programs? 




  1. The table shows how much energy can be recovered from recycling. How might reducing the use of these materials in the first place save even more energy than recovery? Give one example using data from the table.




  1. Aluminum has the highest energy savings when recycled, but it also makes up a smaller portion of household waste than materials like paper or food. How should communities balance energy efficiency (saving the most energy per item) with total impact (saving energy across large waste streams)?




Step 4: Analyze and Reflect

Reflect on what you have learned about energy, waste and every day choices by answering the following questions. 

  1. Which waste recovery method (energy pathway bin) has the greatest potential to benefit your community? Explain why. 





  1. During your own holiday celebrations, what small changes could you make to reduce waste or conserve energy? 





  1. How could your family reuse or repurpose materials from your holiday meal instead of throwing them away? 





  1. What are some barriers that make it difficult for some households to recycle, compost, or donate food? How could these be overcome? 





  1. If you could lead a community campaign about energy and waste after the holidays, what would your main message or call to action be? 





Extension Challenge: CER Activity – Recover or Conserve? 

Driving Question: Is it better to recover energy from waste, or to conserve it by producing less waste in the first place? 

In this challenge, you’ll use a Claim-Evidence-Reasoning (CER) framework to take a position and support it with data (both from your activities and research). 

Step 1: Make a Claim 
State your position clearly in one sentence. Choose one side of the debate or propose a balanced view. 

Sentence Starters: 








Step 2: Use Evidence
Support your claim with specific evidence from the reference table or your own research. Use data or facts to show why your claim makes sense.

Sentence Starters: 












Step 3: Explain Your Reasoning
Connect your evidence to your claim. Explain why your data supports your conclusion and how it answers the driving question. Consider including ideas such as: 

Sentence Starters: