STEM Activity: Coffee Compost

Celebrate International Coffee Day by exploring the science behind composting!

Materials Needed

• Coffee filters
• Used coffee grounds
• Leaves
• Grass clippings
• Craft supplies (stickers, fabric, decorative tape, etc.)
• Drawing utensils (crayons, markers, paints, pencils)
• Used single-use coffee pods
• Paper
• Planting soil
• Scissors
• Small plants or seeds
• Tape
• Water
• Outdoor area for compost

At-Home Instructions

Part 1: Create Compost 

1. Brew a cup of coffee and explain to your kids that the used grounds can be reused to aid plant growth!
    
2. Before using these old grounds in a new way, set aside an area in your yard where you plan to make your compost pile.
    
3. For one month, mix and spread your used grounds and coffee filters along with grass clippings and leaves across your designated compost area. The mixture should have an equal amount of each ingredient.  
    
4. This composted material can now be used as fertilizer for flowers and plants in your home or garden!

Part 2: Upcycle Coffee Pods

While the convenience of single-use coffee pods has made the process of brewing coffee easier than ever, unfortunately, they create a large amount of plastic waste. To mitigate these effects, repurpose these pods by turning them into miniature planters.

1. Have your children sketch their ideas. Will their planter use one pod or many? How will they attach the pods with each other?
    
2. Using tape, scissors, paper, crayons and other craft supplies, have participants design and decorate their planter.
    
3. Next, fill each planter with soil by placing one small plant or seed in the center of each.
    
4. Water each cup regularly to keep them growing.
    
5. If you created compost, add a pinch to each cup to act as a fertilizer.
    
6. Show off your upcycling prowess by taking a photo of your coffee creations and tagging the National Inventors Hall of Fame^® (NIHF) on social media! We always love to see your innovative creations!

Educators: Use this activity in the classroom with these modifications!

Have children work together to create a community or class garden, bringing in coffee grounds and other compostable materials from the teacher’s lounge, student lunches and the cafeteria to compost at school. Research composting best practices online. Create a science experiment by using compost fertilizer on test plants and no compost fertilizer on control plants and compare the difference. Have children create bar graphs to chart plant growth over time. If single-use coffee pods are available, conduct an internet search on creative ways to reuse the pods for the garden or even in the classroom. Get your creativity brewing with all things coffee!

What Are We Discovering?

Humans have been drinking coffee since the 15th century. It has been brewed in many different ways over time, but the process always involves pouring boiling water over ground coffee beans. In 1948, an American inventor and NIHF Inductee, Percy Spencer, invented a special coffee brewing device that harnesses the power of microwave energy.

Because coffee is such a popular drink, used grounds are common in many homes. Often, the grounds are thrown out. However, families can repurpose them to use as composting material. Because coffee grounds are an effective nitrogen source, they are especially effective when mixed with other compostable materials. Creating compost is a great way to reduce landfill waste and create a useful material many people dispose of daily.

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