Have you ever thought about how fish can breathe underwater? It’s pretty amazing! In this article, we’ll learn how fish get the oxygen they need from water, how their breathing is different from ours, and the cool science behind their gills.
People and many animals that live on land breathe air. Air is made up of different gases, with about 21% being oxygen, which we need to live. Our lungs take in oxygen from the air and send it to our blood to keep our bodies working.
Water has much less oxygen than air, usually less than 1%. So, how do fish get enough oxygen to survive in water?
Fish have special organs called gills that help them get oxygen from water. Gills are super efficient, taking up to 85% of the oxygen from the water, while our lungs only take about 25% from the air. This makes gills perfect for fish living in water.
Gills are made of thin, flat parts that are folded many times to create a large surface area. If you could unfold a fish’s gills, they would cover a big space! This large area helps fish quickly swap gases, letting oxygen into their blood and getting rid of carbon dioxide.
Fish breathe by taking water in through their mouths and pushing it over their gills. As the water moves over the gills, oxygen goes into the fish’s blood, and carbon dioxide comes out. Swimming helps fish move water over their gills, making it easier to breathe.
Gills need to stay wet to work well. If a fish is out of water, its gills can dry out, and it won’t be able to breathe. That’s why fish need to live in water; their bodies are made for underwater life.
In short, fish breathe underwater using their gills, which are great at getting oxygen from water. Even though fish and humans both need oxygen, fish have special ways to live where oxygen is hard to find. Learning about how fish breathe shows us how amazing life on Earth is and why it’s important to protect the places where fish live.
If you’re curious about fish and their cool adaptations, feel free to ask more questions!
Gills in Action: Create a simple experiment to understand how gills work. Fill a bowl with water and add a few drops of food coloring. Use a sponge to represent fish gills. Dip the sponge into the water and watch how it absorbs the colored water. Discuss how this is similar to how gills absorb oxygen from water. Ask the children: What do you notice about how the sponge absorbs the water? How do you think this is similar to how fish use their gills?
Fish Observation Walk: If possible, visit a local aquarium or watch a video of fish swimming. Observe how fish open and close their mouths and how their gills move. Encourage the children to mimic the movement of fish breathing. Ask them: Why do you think fish need to keep moving their mouths and gills? How does this help them breathe?
Design a Fish Habitat: Using craft materials, have the children design their own fish habitat. Include elements like water, plants, and rocks. Discuss why each element is important for fish survival. Ask the children: What do fish need in their habitat to help them breathe and live comfortably? How can we help protect these habitats in real life?
