Solar Energy and Photosynthesis

Group of trees with the sun shining through

Solar Energy and Photosynthesis

“Photosynthesis” is a combination of two Greek words that mean “light” and “putting together.” If we consider these meanings, we can understand that photosynthesis is a process that uses sunlight to create something. The ingredients involved in photosynthesis are sunlight, water, and carbon dioxide, which are the things plants need to grow. When we understand how photosynthesis works, we can understand the huge importance of the sun in the lives of plants.

Plants need food to grow and survive, but plants don’t eat the same kinds of foods that humans and animals eat. Plants use solar energy, energy captured from the sun, and they mix it with other things to make their nutrients. This process is called photosynthesis. All living things depend on plants and the process of photosynthesis for survival. Without plants, there wouldn’t be oxygen for humans and animals to breathe, and animals wouldn’t have anything to eat. If animals don’t have plants to eat, humans don’t have animals to eat.

Carbon dioxide is in the air, and it passes through small holes in plant leaves. These holes are called stomata. Plant roots are responsible for absorbing water from the soil. The water moves through the roots, up through the stem, and then to the plant leaves. At the same time the plant is absorbing carbon dioxide and water, it’s also absorbing sunlight, thanks to the chlorophyll in the plant’s cells. The sun’s energy splits the water molecules into oxygen and hydrogen. The plant releases the oxygen out into the air. The hydrogen combines with carbon dioxide, forming glucose that the plant uses to survive. Some of the glucose is used immediately for the plant to grow. The plant also stores some of the glucose in its roots, fruits, and leaves to use later.

Carbon dioxide, one of the things plants need for photosynthesis, is found in the air. As plants absorb carbon dioxide from the environment, they also produce oxygen, which humans and animals need to survive. Chlorophyll is in chloroplasts, which are in plant cells. Chlorophyll helps plants convert carbon dioxide, water, and sunlight into oxygen and glucose.

Although plants need carbon dioxide for photosynthesis, they have other needs, too. Most plants grow in the soil, and they need minerals from the soil to grow. Nitrogen in the soil helps plants grow, and it helps with making leaves. Phosphorus in the soil helps with strong roots. Potassium is essential for flowering plants because it helps with fruit production. To be healthy, plants need the right amounts of nitrogen, potassium, and phosphorus. Sometimes, the soil doesn’t contain enough of these minerals, so fertilizers are added to the soil to help plants grow. Nature also helps to improve the nutrients in soil. Leaves that fall in the autumn contain nitrogen, so mulching leaves and leaving them on the ground can be good for the soil. Covering the topsoil with a layer of leaves also helps keep the soil moist and keeps it from eroding away, which makes the soil healthier, too.

Photosynthesis Vocabulary

  • Absorption: Absorption happens when some of the sun’s energy is taken into a plant.
  • Carbon Dioxide: Carbon dioxide is an odorless gas that is created when people and animals breathe, and it’s absorbed by plants during photosynthesis.
  • Chlorophyll: Chlorophyll gives plants their green color and absorbs sunlight.
  • Chloroplasts: Chloroplasts are small parts of plant cells that capture energy from sunlight.
  • Glucose: Glucose is the nutrient produced by photosynthesis, which plants need to grow.
  • Leaf: A leaf is a large part of a plant attached to the stem that contains chlorophyll and can take in carbon dioxide.
  • Oxygen: Oxygen is an odorless gas that animals need to breathe.
  • Photosynthesis: Photosynthesis is the creation of compounds in plants using sunlight.
  • Xylem: Xylem is a type of tissue in a plant’s veins that moves water and nutrients through the plant.

Additional Resources