TEACHER GUIDE MOLECULES MATTER! STRUCTURE OF PHOTOSYNTHESIS MATERIALS PER GROUP: • Spice drops, Dots candy or colored mini marshmallows Oxygen (different colors) Sunlight • Toothpicks SAFETY PRECAUTIONS: • Do not eat or drink in the labo- ratory. • Please use caution when han- dling the toothpicks as their Carbon ends are sharp. Dioxide TOTAL DURATION: 5 min. pre-lab prep time; 40 min. class time LESSON OBJECTIVES: Water Students will be able to: Minerals 1. Use knowledge of atomic structure to build models of LESSON OVERVIEW: molecules. Plants make the oxygen we breathe and the food we consume. They do this through a process known as photosynthesis. Photosynthesis 2. Rearrange atoms of carbon is the single most important chemical process on the planet because dioxide and water to model the all living creatures depend on it to survive. Without plants, photo- process and products synthesis would not occur and life on Earth would not exist. of photosynthesis. ESSENTIAL QUESTION: How do the structures of atoms relate to their ability to bond? An education and outreach program of: TOPICAL ESSENTIAL QUESTION: How do the atoms in carbon dioxide and water recombine to form glucose during photosynthesis? Noble Research Institute, LLC • 2510 Sam Noble Parkway • Ardmore, OK 73401 • www.noble.org • 580-223-5810 TEACHER GUIDE MOLECULES MATTER! STRUCTURE OF PHOTOSYNTHESIS STANDARDS: Middle School High School HS-PS1-7 MS-PS1-1 HS-PS1-1 Students who demonstrate Students who demonstrate Students who demonstrate understanding will be able to: understanding will be able to: understanding will be able to: Use mathematical representa- Develop models to describe Use the periodic table as a tions to support the claim that the atomic composition of sim- model to predict the relative atoms, and therefore mass, are ple molecules and extended properties of elements based conserved during a chemical structures. on the patterns of electrons in reaction. the outermost energy level of HS-LS1-5 MS-PS1-5 atoms. Students who demonstrate Students who demonstrate understanding will be able to: understanding will be able to: HS-PS1-2 Use a model to illustrate how Develop and use a model to Students who demonstrate photosynthesis transforms describe how the total number understanding will be able to: light energy into stored chemi- of atoms does not change in Construct and revise an expla- cal energy. a chemical reaction and thus nation for the outcome of a mass is conserved. simple chemical reaction based HS-LS1-6 on the outermost electron states of atoms, trends in the Students who demonstrate MS-LS1-7 periodic table, knowledge understanding will be able to: Students who demonstrate of the patterns of chemical Construct and revise an understanding will be able to: properties, and formation of explanation based on evi- Develop a model to describe compounds. dence for how carbon, hydro- how food is rearranged gen and oxygen from sugar through chemical reactions, molecules may combine with forming new molecules that other elements to form amino support growth and/or release acids and/or other large car- energy as this matter moves bon-based molecules. through an organism. Science and Engineering Practices: Crosscutting Concepts: 1. Asking questions 1. Patterns 2. Developing and using models 2. Cause and Effect: Mechanisms and 3. Planning and carrying out investigations explanations 4. Analyzing and interpreting data 3. Scale, Proportion and Quantity 5. Using mathematics and computational 4. Systems and System Models thinking 5. Energy and Matter: Flows, cycles and 6. Constructing explanations and designing conservation solutions 6. Structure and Function 7. Engaging in argument from evidence 7. Stability and Change 8. Obtaining, evaluating and communicating evidence An education and outreach program of: Noble Research Institute, LLC • 2510 Sam Noble Parkway • Ardmore, OK 73401 • www.noble.org • 580-223-5810 TEACHER GUIDE MOLECULES MATTER! STRUCTURE OF PHOTOSYNTHESIS KEY VOCABULARY: Atom Matter Neutrons Valence electrons Compounds Photosynthesis Elements Protons Electrons Atomic number Chemical formula LAB BACKGROUND INFORMATION: NOTE: This is background information for the teacher to assist in facilitating learning and will be explained to the students after the Explore section. Plants make the oxygen we breathe and the food we consume. They do this through a process known as photosynthesis. Photosynthesis is the single most important chemical process on the planet because all living creatures depend on it to survive. Without plants, photosynthesis would not occur and life on Earth would not exist. During photosynthesis, plants use light energy from the sun, carbon dioxide (CO₂) and water (H₂O) to produce energy in the form of glucose (C₆H₁₂O₆) and oxygen (O₂) as a byproduct. As we breathe, we inhale oxygen that is produced by the plants and exhale carbon dioxide that the plants use to make more oxygen. Photosynthesis Equation: Light 6H₂O + 6CO₂ -------------> C₆H12O₆ + 6O₂ Plants convert the glucose that they produce into energy that they need to grow. When we eat plants or plant-derived food, we also use the glucose as energy. In fact, every living creature on the planet uses the glucose produced by plants. Photosynthesis is a chemical process that involves compounds made up of elements found in the periodic table. With a little knowledge about chemistry and the elements, and how they interact, you will be able to build the compounds involved in photosynthesis. Figure 1 Chemistry is the study of the composition, properties and behavior of matter. Matter is anything that has mass and takes up space. The E smallest known unit of matter is the atom. Atoms consist of three particles: protons, neutrons and electrons. E P N N Protons contain a positive electrical charge and are located in the N nucleus of atoms. Neutrons are also located in the nucleus and are P P E electrically neutral, meaning they have no electrical charge. Electrons have a negative electrical charge and move around the nucleus in what is called the atom’s electron cloud, a spherical cloud of varying density surrounding the nucleus that is often depicted as shells or orbits around the nucleus (Figure 1). Electron Proton Neutron An education and outreach program of: Noble Research Institute, LLC • 2510 Sam Noble Parkway • Ardmore, OK 73401 • www.noble.org • 580-223-5810 TEACHER GUIDE MOLECULES MATTER! STRUCTURE OF PHOTOSYNTHESIS An element is matter made of only one kind of atom. Each element E is different and has unique properties. So far, 118 elements have been identified; 98 of them occur naturally. These elements make up gas- es in the air, minerals in rocks and liquids such as water. Examples E of naturally occurring elements include oxygen and nitrogen in the E air you breathe, and metals such as iron, silver and gold. Of all these P = 4 naturally occurring elements, 25 percent are important to living N = 4 E E things. Four of these elements, carbon (C), hydrogen (H), oxygen (O) and nitrogen (N), make up 95 percent of the molecules in living things. E Elements fall into three categories: metals, metalloids and nonmet- als. The elements in each category have similar properties. To help organize and display the elements, chem- ists have created a chart called the periodic table of elements. The periodic table is neatly arranged in rows (left to right) and columns (top to bottom). The rows are called periods. Elements in a period have the same number of electron shells. The columns are called groups or families, and elements in each group have the same number of valence electrons or electrons in the outer- most electron shell. A Bohr model shows the electrons in their shells. The periodic table also contains letters and numbers that describe each element. Each element of the peri- odic table is abbreviated with one or two letters known as the element’s symbol. For example, the symbol for oxygen is O and the symbol for sodium is Na. Numbers for each element represent the element’s atomic number and atomic mass. The number above the symbol is the atomic number, which describes how many protons are in the nucleus of each atom of that element. The number found below the element symbol is the atomic mass, the weighted average mass of an element (Figure 2). This number can vary because of isotopes or atoms of the same element that contain dif- ferent numbers of neutrons. Elements are capable of combining to form a com- Figure 2 pound because of the valence electrons in the out- ermost shell. A compound is a substance in which Atomic Number the smallest unit is made up of atoms of more • number of electrons 21 • number of protons than one element bonded together. Compounds are expressed as chemical formulas; the formula tells you which elements make up a compound as Symbol/Name well as how many atoms (indicated by a subscript number written below and to the right of each ele- Sc44.96 ment’s symbol) of each element exist in one unit of that compound. For example, the chemical formula Atomic Mass for water is H2O, and it is made up of two atoms of • in AMU (atomic mass units) hydrogen (H2) and one atom of oxygen (O). An education and outreach program of: Noble Research Institute, LLC • 2510 Sam Noble Parkway • Ardmore, OK 73401 • www.noble.org • 580-223-5810 TEACHER GUIDE MOLECULES MATTER! STRUCTURE OF PHOTOSYNTHESIS ENGAGE: Prepare several transparent tubes labeled to represent the elements carbon, hydrogen and oxygen, and the compounds sugar and water. The carbon tube can be filled with crushed charcoal or burned wood, and the tubes representing the gases, hydrogen and oxygen, can be left empty. Pass the element tubes around to allow students to observe them and describe them.