The students will then learn what matter is and will review its phases. They will learn about elements and atoms, including the structure of and organization of atoms. The students will then learn about how and why atoms join together to form compounds and molecules. They will then learn the differences between mixtures and solutions and how a solution can be described. The students will then learn about the different types of chemical reactions that can occur. Radioactivity and radioactive isotopes will be explored so that the students will learn what they are and how radioactive exposure is changed by distance and time. The students will then learn about the different types of energy and how energy can be transformed from one type to another. They will explore work and simple machines, along with forces and motion. The students will learn about the properties of magnetism and electricity and how they are related to each other. The differences between temperature and heat will be explained while the students learn about how heat travels. Students will also learn about the nature of light and why some materials absorb light while others do not. They will review the process of photosynthesis, including how the process came to be understood by scientists.