Iron is a metal and vital to life on this planet. It is not only the fourth most abundant element on Earth, but plants, animals, and people need it to survive. In this activity, we will explore where iron comes from, how we use it every day, and how it helps our bodies stay healthy.
Where Iron Comes From
Did you know that the Earth's inner core is made from solid iron and the outer core is mostly made of liquid iron and nickel? Also, 5% of the Earth's crust is made up of iron, making it the 4th most abundant element in the Earth's crust! We can find iron in many rocks, soils, and dark sand. The black sand at Black Sands Beach has an iron called magnetite mixed into it.
Iron plays an important role in our daily lives. Today, many things that we use are made from iron. Some examples are silverware, refrigerators, stoves, knives, stainless steel, and even our cars!
Quick Facts:
- 4th most abundant element on Earth
- 5% of Earth's crust is iron
- Found in rocks, soil, and dark sand
Iron in Food
Iron is also a micronutrient found in food. Plants absorb iron particles (small pieces) from the soil as they grow. Iron helps the plants grow stronger. When we eat the leaves and fruit of the plant, we are also eating part of that iron.
Animals also get their iron from eating plants. That is why eating meat from herbivores (plant-eating animals) can also give you iron. Iron is essential for a healthy human body.
Two Types of Iron in Food
Heme Iron - Found in meat, fish, and poultry. This type of iron is easier for your body to absorb and use.
Non-Heme Iron - Found in plants like spinach, beans, and fortified cereals. Eating Vitamin C foods (like oranges!) helps your body absorb this type better.
💡 Fun Tip: Vitamin C is iron's best friend! Eating an orange with your spinach helps your body absorb more of the plant-based iron.
We Need Iron to Be Healthy
The adult human body contains about 4 grams of elemental iron. That is almost 1 teaspoon of iron (0.8 tsp to be exact). Our body only needs a small amount of iron to be healthy.
Iron helps the body make new red blood cells and is an important part of our body's hemoglobin. Hemoglobin is the part of a red blood cell that binds to oxygen (O₂) and carries the oxygen all over the body. It also carries carbon dioxide (CO₂) out of your blood and to your lungs to be breathed out.
How Your Body Uses Iron
When iron reaches your stomach, acids break it down into tiny pieces. Then your small intestine absorbs the iron and sends it into your bloodstream. From there, it travels to your bone marrow where new red blood cells are made!
How Much Iron Do We Need?
- Children need about 10mg of iron per day
- Adults need between 8-18mg per day
- Women generally need more iron than men because of menstruation
What Happens Without Enough Iron?
When you don't get enough iron, you might:
- Feel tired and weak all the time
- Have pale skin
- Get sick more easily
- Have trouble concentrating in school
- Feel cold more often
Fun Fact: Your Body Recycles Iron!
Did you know that your body is super smart? When old red blood cells die after about 120 days, your body doesn't waste the iron. Instead, it saves and recycles that iron to make new red blood cells. This means the iron in your body right now might have been used dozens of times before!
Making the Connection
Have you ever seen rust? That's iron reacting with oxygen—similar to what iron does in your blood, but controlled by your body in a helpful way!
⚠️ SAFETY NOTE: We get our iron from foods! It is very unsafe to eat rocks to get iron, or to take iron supplements without talking to a doctor first. Too much iron can actually make you sick. Always eat a balanced diet with iron-rich foods instead.
Learning Activity
Iron is in the food we eat. It is broken down into microscopic pieces, but it is still there. In this activity, you will have a chance to pull out the iron from your cereal!
Experiment: Extract Iron from Cereal
Materials:
- Strong Rare Earth Magnet ($10-$15 on Amazon)
- ¾ cup Total Cereal (or other iron-fortified cereal)
- Blender
- Clear plastic cup
- ¾ cup water
- Plastic spoon
Instructions:
- Place ¾ cup of Total cereal into your blender with ¾ cup of water.
- Blend up the mixture until it's smooth, then pour it into a clear plastic cup.
- Place your magnet on the side of the cup for about 1-2 minutes.
- Watch carefully as the small iron particles collect right next to the side of the cup!
🎯 Fun Tip: If you put iron-rich cereal like Total on top of water in a bowl, it will float and follow your magnet around! Try it!
Observe & Think
These iron particles are the same iron that you see in rocks. They are just broken down into a smaller, easier-to-digest form. It might look strange, but our body needs it! We just need a small dose of iron from our food every day.
Discussion Questions:
- Why do you think cereal companies add iron to their products?
- How is the iron in cereal different from a nail or paperclip?
- What other foods do you eat that might contain iron?
Extension Activity: Iron Content Research
Now that you know iron is in our food, let's explore which foods have the most iron!
Your Mission:
- Research and find the iron content (in mg) of these foods:
- 1 cup of cooked spinach
- 3 oz of beef
- 1 cup of lentils
- 1 apple
- 1 serving of fortified cereal
- ¼ cup of raisins
- Create a chart or bar graph showing which foods have the most iron.
- Calculate: If you're a kid who needs 10mg of iron per day, how many servings of each food would you need to eat?
- Plan a one-day meal plan that includes at least 10mg of iron from different food sources.
Think About It:
- Which foods surprised you with their iron content?
- Why do you think it's important to eat a variety of iron-rich foods instead of just one?
- Remember: Vitamin C helps your body absorb plant-based iron. Which Vitamin C foods could you pair with your iron-rich plant foods?
Amazing Iron Facts
- Your body contains enough iron to make a nail about 3 inches long!
- Red blood cells live for about 120 days before they're recycled.
- Your body makes about 2 million new red blood cells every single second!
- The red color of your blood comes from iron in hemoglobin.
- Ancient people made tools and weapons from meteorites that fell from space—these space rocks were rich in iron!