Hey there! Today, we’re going to learn about how our bodies move, just like a robot named Squeaks. Squeaks is a robot, so he moves with motors. But our bodies work a bit differently. We use muscles to move! Let’s dive into how our bodies move and stay healthy.
Our bodies have lots of different parts, and scientists group them into body systems. To move, we need three main systems: the muscular system, the skeletal system, and the nervous system. Let’s explore each one!
The muscular system is made up of muscles. Muscles are like stretchy rubber bands that help us move. They can contract (squeeze together) and relax (stretch out). For example, when you bend your arm, your bicep muscle contracts and gets shorter and thicker. When you straighten your arm, it relaxes and gets longer and thinner.
The skeletal system is made up of bones. Bones are hard and sturdy, and they support our muscles. Muscles are attached to bones with strong cords called tendons. When muscles contract, they pull on the bones, making them move.
The nervous system is like the body’s command center. The brain is the most important part. It sends signals to the muscles, telling them when and how to move. For example, if you want to pick up an apple, your brain sends signals to your hand and arm muscles to help you grab and lift the apple.
Now, let’s talk about how we see colors. Our eyes have a special part called the retina, which helps us see. The retina has two types of parts: rods and cones. Rods help us see in the dark, and cones help us see colors.
There are three types of cones: those that see red, green, and blue. When light bounces off an object, like a red apple, the cones send a message to the brain about the colors they see. Most people can see all the colors of the rainbow, but some people are colorblind, meaning they have trouble seeing certain colors.
People who are red-green colorblind have trouble seeing red and green clearly. They might see these colors as dull or similar. There are also people who are blue-yellow colorblind, meaning they have trouble telling blue and yellow apart.
Different animals see colors differently. For example, dogs have only two types of cones, so they see the world a bit like red-green colorblind people. Some animals, like the mantis shrimp, have many more types of cones and can see a wide range of colors, even ultraviolet light, which humans can’t see!
Our skeleton is super important. It holds our body up and protects our organs. Without it, we’d be all floppy! Our muscles work with our skeleton to help us move.
The strongest bone in our body is the femur, which is in our leg. It’s big and strong because it supports a lot of our weight. The smallest bone is in our ear, called the stapes, and it’s tiny but helps us hear sounds.
When we’re born, we have about 300 bones, but as we grow, some bones fuse together, leaving us with 206 bones as adults. Our bones are alive and full of cells that help them grow and repair. They even make our blood!
Our tonsils are little lumps in the back of our throat that help protect us from germs. They trap germs that come in through our mouth or nose. Sometimes, they can get swollen and sore, which is called tonsillitis. If tonsillitis happens a lot, doctors might suggest removing the tonsils, but don’t worry, we can still be healthy without them.
Our bodies are amazing machines with muscles, bones, and nerves all working together to help us move, see, and stay healthy. Remember to take care of your body by exercising and eating well. If you have any questions about your body or going to the doctor, feel free to ask!
Muscle Movement Experiment: Let’s explore how our muscles work! Find a rubber band and stretch it with your fingers. Notice how it gets longer and thinner when you pull it and shorter and thicker when you let go. Now, try bending your arm and feel your bicep muscle. Can you feel it getting shorter and thicker like the rubber band? Try this with different muscles in your body and see how they work!
Bone Building Challenge: Use building blocks or modeling clay to create a simple skeleton. Think about how bones support our body. Can you make a structure that stands up on its own? Once you’ve built your skeleton, try attaching “muscles” using rubber bands or string. How does adding muscles change the way your skeleton can move?
Color Vision Exploration: Gather some colored paper or crayons in red, green, and blue. Look at each color and think about how your eyes and brain work together to see them. Now, mix two colors together, like red and blue, to make purple. What happens when you mix different colors? Try drawing a picture using only these colors and see what new colors you can create!
