# What is photosynthesis?

An episode of [Science for Kids / Science's Not Boring: The Kids Science Podcast](https://invisiblenetwork.ai/podcast/1896928296), 21 Aug 2026, 14 min.

Audio: https://www.buzzsprout.com/2624612/episodes/19649956-what-is-photosynthesis.mp3

Take a deep breath in... and let it out. Did you know that every single molecule of oxygen you just breathed was created by a plant? In this thrilling episode, Mira and Finn uncover the invisible superpowers of plants and trees! Join our hosts as they journey from the tiny, microscopic mouths on leaves (called stomata!) all the way to the steamy, massive Amazon Rainforest. You will discover how trees act like giant vacuum cleaners that suck up bad air and burp out fresh oxygen through a magical recipe called photosynthesis! Plus, learn about incredible "flying rivers" in the sky made of 20 billion tons of tree sweat, the amazing Dutch scientist who figured out plant secrets in 1779, and the shocking truth about how tiny ocean bacteria actually make most of Earth's oxygen! Pack your explorer hat and get ready to find out why keeping our forests safe is the most important mission on the planet. Tune in and never look at a leaf the same way again!

## Transcript

[0:46] SPEAKER_00: Welcome to Science Is Not Boring by kidopoly.com.
[0:50] SPEAKER_00: I'm Mira.
[0:51] SPEAKER_00: And I'm Finn.
[0:53] SPEAKER_00: Before we start, we have a massive shout out.
[0:56] SPEAKER_00: A big hello to Junior, who is five years old and listening all the way from Calgary, Alberta, in Canada.
[1:03] SPEAKER_01: Hi Junior, thanks for tuning in from Calgary.
[1:06] SPEAKER_01: I bet it's beautiful there.
[1:08] SPEAKER_00: Junior asked us to do an episode all about South American rainforests.
[1:13] SPEAKER_00: That is an amazing request, Junior, and this entire episode is dedicated to you.
[1:18] SPEAKER_00: We're trading the chilly Canadian mountains for the steamy jungle.
[1:23] SPEAKER_01: So we're going to the rainforest today.
[1:26] SPEAKER_01: I need my explorer hat.
[1:28] SPEAKER_00: We sure are.
[1:29] SPEAKER_00: But first, Finn, I want you to take a big deep breath in and let it out.
[1:37] SPEAKER_00: Ah.
[1:38] SPEAKER_00: Okay, I did it.
[1:40] SPEAKER_00: You take about 20,000 breaths every single day.
[1:44] SPEAKER_00: That is over 7 million breaths a yeah.
[1:48] SPEAKER_00: But did you know that every single molecule of oxygen you just breathed in was created by plants and tiny ocean life.
[1:56] SPEAKER_00: Wait, every single breath?
[1:59] SPEAKER_00: For my whole life.
[2:01] SPEAKER_00: Exactly.
[2:02] SPEAKER_00: Every time you sigh, every time you laugh, every time you pant after running fast, you can thank a plant.
[2:09] SPEAKER_00: Today, we are exploring the invisible superpowers of plants and trees.
[2:14] SPEAKER_01: Haha, I thought they just stood there looking pretty and dropping leaves on the lawn.
[2:20] SPEAKER_00: Oh, they are doing so much more.
[2:22] SPEAKER_00: We are going to discover how leaves act like tiny air cleaning factories, how the giant Amazon rainforest can literally make its own rain.
[2:31] SPEAKER_00: And why the survival of our whole planet depends on the quiet power of a leaf.
[2:36] SPEAKER_01: Okay, so I know trees have leaves, branches, and deep roots.
[2:41] SPEAKER_01: But how do they actually make the air clean?
[2:44] SPEAKER_01: They don't have lungs like humans or animals, right?
[2:47] SPEAKER_00: Well, not exactly lungs.
[2:50] SPEAKER_00: But if you took a leaf from your backyard and put it under a powerful electron microscope, you would see that its surface isn't smooth at all.
[2:59] SPEAKER_00: It is covered in thousands of tiny microscopic mouths.
[3:04] SPEAKER_01: Wait, mouths?
[3:05] SPEAKER_01: Like with teeth and tongues?
[3:07] SPEAKER_00: That's a little freaked out.
[3:10] SPEAKER_00: No teeth.
[3:11] SPEAKER_00: They are called stomata.
[3:13] SPEAKER_00: Stomata are tiny pores or holes that look just like a pair of tiny green lips.
[3:20] SPEAKER_00: They open and close all day long to let air in and out.
[3:24] SPEAKER_00: That's wild! How many of these tiny lips are on one leaf?
[3:29] SPEAKER_00: A single square centimetre of an oak leaf, which is about the size of your fingernail, can have over 100,000 stomata.
[3:39] SPEAKER_01: 100,000?
[3:40] SPEAKER_01: On just a fingernail-sized piece of a leaf?
[3:43] SPEAKER_01: That means a whole tree has trillions of them.
[3:47] SPEAKER_00: Yes, and human beings have known about this plant's superpower for a long time.
[3:52] SPEAKER_00: Back in the year 1779, a Dutch scientist named Jan Ingenhaus did a brilliant experiment.
[4:00] SPEAKER_00: What did he do?
[4:01] SPEAKER_00: Did he use a microscope too?
[4:03] SPEAKER_00: He actually used a simple glass bowl.
[4:06] SPEAKER_00: He took some green willow branches and put them completely underwater in a clear container.
[4:13] SPEAKER_00: Did the branches drown?
[4:14] SPEAKER_00: Plants need air too.
[4:16] SPEAKER_00: Nope.
[4:17] SPEAKER_00: When he put the glass container in bright, blinding sunlight, he noticed something amazing.
[4:24] SPEAKER_00: Tiny bubbles were forming all over the leaves.
[4:27] SPEAKER_00: But when he moved the container into a dark closet, the bubbles completely stopped.
[4:32] SPEAKER_00: What were the bubbles made of?
[4:34] SPEAKER_00: Pure oxygen.
[4:36] SPEAKER_00: Jan discovered that plants need the energy of sunlight to create the oxygen that we breathe.
[4:42] SPEAKER_00: It was a massive scientific breakthrough that changed how we understand nature.
[4:47] SPEAKER_01: So the tiny leafy mouths, the stomata, they breathe out oxygen bubbles.
[4:53] SPEAKER_00: Exactly! But it is part of an incredibly complex chemical recipe called photosynthesis.
[5:00] SPEAKER_00: Photo is a Greek word that means light, and synthesis means putting things together.
[5:06] SPEAKER_01: So they take sunlight and put it together with.
[5:10] SPEAKER_01: what else?
[5:11] SPEAKER_00: Here is the magical recipe.
[5:13] SPEAKER_00: First, the plant drinks up water through its roots.
[5:17] SPEAKER_00: Then, its millions of tiny stomata mouths breathe in a gas from the air called carbon dioxide.
[5:24] SPEAKER_00: Carbon dioxide?
[5:25] SPEAKER_00: Isn't that the waste gas we breathe out when we exhale?
[5:29] SPEAKER_00: Yes! It is also the heavy gas that comes out of car exhaust pipes and factory smokestacks.
[5:36] SPEAKER_00: Too much carbon dioxide acts like a thick blanket, trapping heat and making our planet way too hot.
[5:43] SPEAKER_00: But to a plant, carbon dioxide is a delicious meal.
[5:47] SPEAKER_00: So they basically eat the bad air.
[5:50] SPEAKER_01: That's incredibly helpful.
[5:52] SPEAKER_00: They do! Inside the leaf, there are tiny green factories called chloroplasts.
[5:58] SPEAKER_00: A single plant cell can have a hundred of them.
[6:01] SPEAKER_00: They grab the sunlight, the water, and the carbon dioxide, and they mash them all together.
[6:07] SPEAKER_01: And what comes out of these tiny green factories?
[6:10] SPEAKER_00: Two very important things.
[6:13] SPEAKER_00: First, they create a sugar called glucose that travels in the sap to feed the plant and help it grow tall.
[6:20] SPEAKER_00: And the leftover waste from making that sugar?
[6:23] SPEAKER_00: That is pure clean oxygen.
[6:25] SPEAKER_00: The plant just pushes it out into the air.
[6:28] SPEAKER_01: So every time I take a deep breath of fresh air, I am basically breathing in a plant burp.
[6:34] SPEAKER_00: Yep! A very clean, life-saving, microscopic plant burp.
[6:40] SPEAKER_00: And because plants suck up so much carbon dioxide, they act like giant vacuum cleaners for the entire earth, scrubbing our atmosphere clean.
[6:49] SPEAKER_01: Okay, so if one tiny leaf does that much work, a whole huge forest must be doing a ton of vacuuming.
[6:56] SPEAKER_01: Is that why Junior wanted to know about the South American rainforest?
[7:00] SPEAKER_00: You guessed it! Junior, pack your bags.
[7:04] SPEAKER_00: We are heading straight into the heart of the Amazon rainforest.
[7:08] SPEAKER_00: This jungle is so massive, it covers 5.5 million square kilometres across nine different countries in South America.
[7:18] SPEAKER_01: Whoa! 5.5 million?
[7:21] SPEAKER_01: That's big enough to cover almost the entire continent of Australia.
[7:25] SPEAKER_01: How many trees can fit in a space that gigantic?
[7:29] SPEAKER_00: Scientists estimate there are 390 billion individual trees in the Amazon.
[7:36] SPEAKER_00: And they aren't just one type of tree either.
[7:38] SPEAKER_00: There are over 16,000 different species.
[7:42] SPEAKER_00: Some, like the giant kapok tree, shoot up 200 feet into the sky.
[7:48] SPEAKER_01: 390 billion?
[7:50] SPEAKER_01: That's like 50 huge trees for every single person on Earth.
[7:55] SPEAKER_01: You got it!
[7:56] SPEAKER_00: And because it is so massive, scientists often call the Amazon the lungs of the planet.
[8:03] SPEAKER_00: All those billions of giant trees are pulling in carbon dioxide and breathing out oxygen during the day while they rest at night.
[8:12] SPEAKER_00: Do they do anything else besides making oxygen and sugar?
[8:15] SPEAKER_00: Oh, they do something unbelievable.
[8:18] SPEAKER_00: They make their own weather.
[8:20] SPEAKER_00: Have you ever heard of a flying river?
[8:22] SPEAKER_01: A river flying in the sky?
[8:25] SPEAKER_01: No way.
[8:26] SPEAKER_01: Water is way too heavy for that.
[8:28] SPEAKER_00: Way! Trees pull up water from the soil and sweat water vapour out of their stomata.
[8:34] SPEAKER_00: This is called transpiration.
[8:36] SPEAKER_00: The Amazon trees release about 20 billion tonnes of water vapour into the air every single day.
[8:43] SPEAKER_00: 20 billion tonnes of water floating in the air.
[8:47] SPEAKER_00: Yes.
[8:48] SPEAKER_00: This massive amount of invisible water forms giant flowing clouds that look just like a river in the sky.
[8:56] SPEAKER_00: These clouds eventually rain back down, keeping the entire jungle perfectly wet and alive.
[9:03] SPEAKER_01: 20 billion tonnes of water sweating out of leaves.
[9:08] SPEAKER_01: That is heavier than all the giant skyscrapers in New York City.
[9:13] SPEAKER_01: But wait, what happens if those trees disappear?
[9:16] SPEAKER_00: That is the really scary part.
[9:19] SPEAKER_00: When giant forests are chopped down or burned in wildfires, they stop cleaning the air completely.
[9:26] SPEAKER_00: But it gets worse.
[9:27] SPEAKER_00: All the carbon dioxide they sucked up over hundreds of years gets released right back into the sky.
[9:34] SPEAKER_01: Oh no.
[9:35] SPEAKER_01: So the vacuum cleaner basically breaks and dumps out all the dirt.
[9:39] SPEAKER_00: Exactly.
[9:40] SPEAKER_00: The Amazon currently stores over 150 billion metric tons of carbon inside its trees and the soil.
[9:49] SPEAKER_00: That is equal to the weight of a billion blue whales.
[9:54] SPEAKER_01: So if we lose the forest, we lose our giant air filter, all that carbon escapes, and the planet gets way hotter.
[10:01] SPEAKER_00: You nailed it.
[10:03] SPEAKER_00: That is why protecting the rainforest isn't just about saving jaguars in colourful macaws.
[10:08] SPEAKER_00: It's about saving the whole planet's climate.
[10:12] SPEAKER_00: But hey, are you ready for a mind-blowing, weird, fun fact about oxygen?
[10:17] SPEAKER_00: Always hit me with the weird facts.
[10:20] SPEAKER_00: While forests are super important, the absolute biggest oxygen factory isn't on land at all.
[10:27] SPEAKER_00: The ocean makes over 50% of our oxygen, and a tiny green bacteria called Prochlorococcus makes 20% all on its own.
[10:38] SPEAKER_01: Wait, a tiny bacteria in the ocean makes 20% of our oxygen.
[10:44] SPEAKER_00: Yes, it was discovered by a brilliant scientist named Sally Chisholm in 1988.
[10:50] SPEAKER_00: She used a special laser machine to find them.
[10:53] SPEAKER_00: They are so small that millions can fit in a single drop of seawater.
[10:59] SPEAKER_00: But there are billions of billions of them in the ocean.
[11:03] SPEAKER_01: So the tiny ocean bacteria and the giant rainforests are teaming up every single day just to keep us breathing.
[11:11] SPEAKER_01: That is amazing.
[11:12] SPEAKER_01: Alright Finn, it's time for the quiz.
[11:14] SPEAKER_01: Are you ready?
[11:15] SPEAKER_01: Okay, I'm ready.
[11:17] SPEAKER_01: I hope I remember all those massive numbers.
[11:19] SPEAKER_00: First question.
[11:21] SPEAKER_00: What are the microscopic lip-shaped mouths on leaves called?
[11:28] SPEAKER_00: Next one.
[11:29] SPEAKER_00: Who was the Dutch scientist that discovered plants make oxygen in sunlight all the way back in 1779?
[11:37] SPEAKER_00: Question three.
[11:39] SPEAKER_00: How many billions of trees are estimated to be growing in the Amazon rainforest?
[11:48] SPEAKER_00: Here's number four.
[11:49] SPEAKER_00: What do we call the massive clouds of water vapour the Amazon trees sweat into the air every day?
[12:00] SPEAKER_00: Last question.
[12:01] SPEAKER_00: What is the name of the tiny ocean bacteria that makes a huge amount of Earth's oxygen?
[12:11] SPEAKER_00: Great job! Let's see how you did.
[12:14] SPEAKER_00: The first answer is stomata, those are the tiny mouths.
[12:19] SPEAKER_00: For question two, the scientist was Jan Ingenhaus.
[12:23] SPEAKER_00: The answer to question three is 390 billion trees.
[12:29] SPEAKER_00: For question four, they are called flying rivers.
[12:34] SPEAKER_00: And the final answer is Prochlorococcus.
[12:38] SPEAKER_00: That one is super hard to say.
[12:40] SPEAKER_01: Wow! From microscopic lips on leaves to giant flying rivers in the sky, plants are basically silent superheroes.
[12:49] SPEAKER_01: I'm definitely going to say thank you to the next tree I see outside.
[12:54] SPEAKER_00: You definitely should.
[12:56] SPEAKER_00: They are working hard every single day, silently scrubbing the sky just to keep our air clean.
[13:03] SPEAKER_01: If you loved exploring the deep, steamy rainforest with us today, please leave us a five-star review.
[13:09] SPEAKER_00: Yes! Just scroll down on your podcast app and tap those five stars so we can grow our show to be as massive as the Amazon's 390 billion trees.
[13:20] SPEAKER_01: Oh, and don't forget to check out our site kidopoly.com.
[13:25] SPEAKER_01: We've got tons of fun learning games, activities, and cool science stuff for you to explore there.
[13:31] SPEAKER_00: And if you want a special shout out on the show, just like Junior got today, or if you just want to say hi, send us an email at hello at kidopoly.com.
[13:41] SPEAKER_00: We absolutely love reading your messages.
[13:44] SPEAKER_00: See you next time on Science is not boring.
[13:48] SPEAKER_00: Bye everyone.
[13:49] SPEAKER_00: Keep breathing that wonderful plant air!

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