At a Glance
🎯
WHAT THEY'LL LEARN
How stretching stores energy, and how that energy becomes motion
📖
HOW TO USE
Before, during, or after the episode
⏱️
TIME NEEDED
13 min read + 25 min activity
⏱️
PREP REQUIRED
Craft sticks, rubber bands, a plastic spoon, marshmallows
How to Use This Guide
A simple flow for busy parents
Listen to the Episode
"Mini Marshmallow Catapult" walks through the whole build step by step — listen together before starting construction.
Talk About Key Ideas
Ask your child what they think happens to the rubber band's energy when they pull the spoon back.
Try an Activity (Optional)
Build a real catapult out of craft sticks and rubber bands, then launch marshmallows at a target — about 25 minutes, one of the most popular activities of the season.
Review Vocabulary
Practice "elastic potential energy" and "kinetic energy" together — these are big words, but the idea behind them is simple and visual.
FOR BUSY PARENTS
This is consistently one of the most-loved episodes — worth setting aside a full 25 minutes if you can, since kids tend to want to keep launching long after the activity ends.
Learning Goals
What your child will understand after this
🎯
Big Idea: Stretching Stores Energy
Your child will understand that pulling back a stretchy rubber band stores energy inside it, and that letting go releases all of that energy as motion.
🔬
Scientific Process
They'll watch Fix build a real device, then test 3 different pull-back distances and compare how far the marshmallow flies each time.
🌍
Real-World Connection
They'll connect this to trampolines, slingshots, and bows — anything stretchy that stores energy and releases it as motion.
💬
Skills Supported
Following multi-step build instructions, testing a variable (pull-back distance), measuring results, and explaining energy transfer.
Conversation Starters
Questions to spark deeper thinking (not right/wrong answers!)
🎈
For Younger Learners (Ages 5-6)
"What happened when you pulled the spoon back and let go?"
"Did pulling back farther make the marshmallow go farther or shorter?"
"What else do you know that stretches and then snaps back?"
🚀
For Older Learners (Ages 7-8)
"Where is the energy stored before you let go of the spoon?"
"Why does pulling back farther store more energy?"
"How is this catapult similar to a real medieval siege weapon?"
Helpful Vocabulary
Key science words to practice together
Acid
Say it: (ASS-id)
A type of substance, like vinegar or lemon juice, that can react with other things and tastes sour!
Oxidation
Say it: (ok-sih-DAY-shun)
A chemical reaction with oxygen that can cause metal to rust — or invisible ink to appear!
Chemical Reaction
Say it: (KEM-ih-kul ree-AK-shun)
Activities to Try
Hands-on ways to see photosynthesis in action
🍡
Spy Invisible Ink Investigation
⏱️20 minutes
👶 Easy
Write secret messages with lemon juice invisible ink, then compare 4 different liquids to find the best invisible ink — and reveal messages using heat!
NEVER use a candle or open flame — a warm lamp bulb only, with an adult holding and moving the paper.
Extend the Learning
Real-world connections and deeper exploration
🏡
Everyday Connections
Point out other stretchy, energy-storing objects around the house — rubber bands, trampolines, and even a bouncy ball compressing on impact.
🌍
Real-World Impact
Engineers use this same stored-energy principle to design everything from archery bows to the suspension systems in cars.
📚
Further Exploration
Set up a target 3 feet away and challenge your child to hit it — adjusting pull-back distance and aim until they succeed.
🎨
Creative Extension
Have your child design and decorate their own "Catapult Engineer" certificate after completing the distance challenge.
Additional Support
🏠 Homeschool and Classroom Notes
This guide pairs well with a hands-on chemistry unit. The Spy Invisible Ink Investigation activity (20 minutes) works as a structured lab activity, and the discussion questions above can double as journal prompts. Suitable for small-group or whole-class use with adult supervision where the safety note applies.
📋 Standards Alignment
This episode and activity support NGSS Chemistry standards appropriate for K-2, with connections to scientific observation, prediction, and cause-and-effect reasoning. See the matching episode and activity CMS records for the specific standard codes.