You can teach second grade students a simplified process of photosynthesis by growing plants near the windows in your classroom. Start the plants from the seed stage so that students can witness the sun's impact of on the growth of plants. Dedicate a couple hours on a sunny afternoon to have the student watch and help plant a few seeds. Over the course of the next few weeks, use the sprouting of the seeds and their gradual growth to discuss with the students how plants use energy from sunlight to change the air into energy to grow.
Science projects on the sun can make for very visual lessons for second-grade students. Because children can see the sun on most days, they will be more likely to understand your discussions and diagrams on the earth's movement around the sun. Use poster board to draw a diagram of the earth and the sun and their locations in the solar system. Use arrows to show the students that the earth moves around the sun, and have the students color the diagrams with earth and sun tones.
Their own shadows usually mesmerize children, so shadows are a perfect way to incorporate a science project about the sun for second-grade students. Choose three sunny days to create a shadow project where you take the students outside at three different times: 10 a.m., noon and 2 p.m. Have the students stand in the same place each day and talk to them about how their shadow shows the sun's movement in the sky, but it is really the earth's movement in the solar system as the time passes throughout the day.
Show second-grade students how the sun can create thermal heat by placing a piece of fabric in the sun for a few hours. Have the students come up to feel the warm fabric and explain to them how the sun makes the fabric warm, and how humans can turn this heat into energy and use it to power schools, homes and even cars.