Brains On! Science Podcast for Kids

Episode: Why doesn’t stomach acid burn right through us?
Date: February 10, 2026
Host: Molly Bloom
Kid Co-host: Wesley from Columbia, Missouri

Episode Overview

This episode tackles the fascinating question: “Why doesn’t the acid in our stomach burn a hole right through us?” Host Molly Bloom and her kid co-host, Wesley, take listeners on a journey inside the stomach to understand how such a powerful, dangerous substance can break down food—without harming the stomach itself. Alongside fun games, animal facts, and science history, the hosts explore the stomach’s defenses and highlight just how amazing our digestive system really is.

Key Discussion Points & Insights

1. What is Stomach Acid and How Strong Is It?

• Stomach acid, aka gastric juice, is a potent mixture made up of hydrochloric acid, digestive enzymes, water, and other components.
• “Not only does it break down food, but outside of the body it can burn skin. Given enough time, it can even dissolve some metals like zinc.” – Molly (03:55)
• The human body produces 3–4 liters (about two big party-sized soda bottles) of this acid every day.
  —[04:16]

2. Why Doesn’t Stomach Acid Burn Through Our Stomachs?

Guest: Mark and his "Organophone" invention (lets them “call” the stomach for an interview!)

• The stomach protects itself using mucus, which lines its walls and acts as a shield.
• This mucus is rich in bicarbonate, which neutralizes acid and prevents tissue damage.
  • “There are these glands in me that make a lot of mucus. And that mucus acts like a shield protecting my walls from all that nasty acid. Plus, the mucus is full of stuff called bicarbonate.” – “Stomach” (08:16)
• Stomach cells are constantly shedding and regenerating. The lining of the stomach is replaced every few days, giving the stomach a fast-repair “armor”.
  • “Mine sort of sacrifice themselves constantly. They fall off the walls of me, the stomach… In fact, the entire lining of the stomach is replaced every couple days.” – “Stomach” (09:26, 09:53)
• Bicarbonate in the mucus acts like a natural baking soda:
  • “Bicarbonate is super alkaline. And when you mix acids and alkaline stuff together, they sort of cancel each other out.” – Mark (08:55)

Notable Memorable Quote:

“Oh Molly, I have my ways. And by ways I mean mucus.” — “Stomach” (07:50)

3. Fun and Games: Mystery Sound and Digestion Across the Animal Kingdom

• Regular segments like the Mystery Sound keep engagement high, with kids guessing real-world sounds ([11:38–12:38], [26:55]).
• Game Show Segment – Digestion Suggestion explores unusual animal digestion:
  • Cows: Eat food, regurgitate, chew again ("chewing cud"). — [16:25]
  • Ostriches/Birds: Swallow rocks to grind food in their gizzard. — [17:10]
  • Egg-Eating Snakes: Swallow eggs whole, crack them internally, and regurgitate the shells. — [18:09]
  • Vultures: Eat rotting meat, have super-strong stomach acid to kill germs. — [18:57]

Memorable Moment:

“If you could have the power to digest anything in the world, what would you want and why?”
— Molly (20:04)
“If I got to eat a microphone and then spit it back out like the cow, would I just get a really loud voice for a long time?”
— Wesley (20:10)

4. History of Stomach Science

• The story of Alexis St. Martin and Dr. William Beaumont (1822):
  • St. Martin’s stomach wound never fully healed, creating a “window” into his stomach.
  • Beaumont used strings to place and remove food from St. Martin’s stomach, learning about digestion by direct observation. — [24:10–25:10]
  • Questions raised about the ethics of these early experiments: Was it right to experiment on someone in exchange for food and shelter? — [25:15–26:08]
• Modern standards now require experiments to be ethical, safe, and approved by review boards.

5. Review and Recap of Key Takeaways

• Stomach acid is extremely strong, able to break down food—and dangerous outside the body.
• The stomach protects itself with a thick mucus layer and neutralizes acid using bicarbonate.
• Stomach lining regenerates every couple of days, quickly repairing any acid damage.
• Many animals have incredible adaptation to digest different foods—from regurgitating partly digested food to eating rocks or eggshells.
• Ethical science has come a long way since early experiments.

Notable Quotes & Memorable Moments

• Mucus as a hero:

  “Mucus is the absolute queen… I’m team Mucus all the way.” – Molly (08:01)

• Stomach’s voice:

  “Hey, I want food. Give me grilled cheese. I’m hungry.” – Wesley (03:08)

• Fun with beans:

  “All of me loves beans. Beans, frijoles, black and pinto we love them at the table, we love them on the go Beans, frijoles, pinto and black Like a song in the mouth and music in the back.” – Mark & Cast (11:15)

• On science ethics:

  “Today, scientists who want to do an experiment are supposed to explain it to a group of other scientists. And those other scientists make sure that the experiments are ethical, which means it is safe, fair, and no one is treated badly.” – Molly (26:01)

Important Timestamps

• 00:16–00:36: Introduction to stomach acid's power
• 02:11: Main question—“How does your stomach acid break down your food but not hurt your stomach?”
• 03:55: Explanation of stomach acid’s strength
• 06:23–09:53: Organophone segment; “interview” with the stomach; mucus & bicarbonate explained
• 15:14: Introduction to digestion in the animal kingdom game
• 24:10: Story of St. Martin & Dr. Beaumont—early human stomach research
• 26:01: Ethics of experimentation explained
• 26:31: Summary of the stomach's protective mechanisms

Tone & Language

The episode maintains a friendly, playful, and accessible tone, featuring jokes, puns, fictional “interviews,” and kid co-host contributions. Technical terms are broken down with analogies and humor, making complex biology understandable and fun for young listeners.

Engaging for All Ages

“Brains On!” balances solid science, memorable stories, and interactive fun, ensuring that both kids and adults stay curious—and better informed about just how amazing our insides are!