After this activity, students should be able to:

• List the basic components and structure of the atom.
• Identify the electrical charge of an atom and its subatomic particles.
• Explain how engineers use their knowledge of atoms to create new technologies.

Have you ever wondered what everything around you is made of? Are things made up of tiny particles that we cannot see? Yes, they are. These tiny building blocks of matter are called atoms and they make up everything we see around us, even ourselves. In this activity, we are going to learn about the atom. We will learn about the parts of an atom, its structure, and learn how to determine the charge of an atom.

Can the atom actually be broken down into smaller parts? Yes, it can. There are several subatomic particles that make up an atom. The three main ones are the protons and neutrons, which are found in the nucleus or core of the atom, and electrons, which are found floating around in shells outside of the nucleus. Scientists have also discovered that atoms contain other tiny subatomic particles floating alongside the electrons, called neutrinos. Also, protons and neutrons are made up of even tinier particles called quarks. Today, however, we are just going to look at protons, neutrons and electrons.

Did you know that atoms have energy? Well, these tiny subatomic particles are constantly moving or vibrating and we cannot even tell. For example, if you look at a molecule of water, it is made up of two hydrogen atoms and one oxygen atom. The electrons in each of these atoms that make up the water molecule are moving all around in their electron shells, or clouds. The outermost electrons in an atom are sometimes shared with another atom. That is how the molecule is formed. The large oxygen atom in a water molecule shares electrons with the hydrogen atoms.

How is this sharing possible? Well, it depends on the electrical charge of the atom. Each of our three subatomic particles in the atom has a type of charge. Protons have a positive charge or +1 charge on them. Electrons have a negative charge or a -1 charge to them. Neutrons are neutral or have no charge. When the overall charge of an atom is neutral, then there are an equal number of protons and electrons. If there are more protons than electrons, though, the atom is positively charged. If there are more electrons than protons, the atom is negatively charged. Any atom with a positive or negative overall charge is called an ion.

Do you think we can apply our knowledge of atoms and their structure to engineering? Yes! For example, how do engineers know that steel is extremely strong? Engineers know this because they know the characteristics of the atoms that make up steel. They know how the parts of each atom interact with each other to create a compound that has specific properties. Engineers and scientists have even been able to develop new atoms and elements that have specific properties that they need to create certain materials and technologies. Engineers use atoms, knowledge of their structure and how they bond, to make new medicines and products to help people. For example, environmental engineers need to know the properties of water molecules and the atoms that make up water molecules to design clean water and air treatment technologies to fight pollution.

Remind the students that the gumdrops are for learning, not eating. It often helps to have an extra bag of gumdrops for the students to share and eat after the activity.

The students can use staples or glue to attach the sticker dots if they do not stick to the gumdrops.

Human Lithium Atom: This activity demonstrates the huge amount of space between the nucleus and the electrons and dispels the common misconception that the electrons are located close to the nucleus. Have students make a human model of a lithium atom (same number of protons, neutrons and electrons as the gumdrop activity) on the playground or in the gymnasium. Students can wear T-shirts or caps of the same color, if possible, to represent protons, electrons and neutrons. Students can add pluses, minuses, or zeros, made out of electrical tape, to their shirts. Next, have students act in the roles of the protons, neutrons and electrons, with the "nucleus" (protons and neutrons) as close to the center of the playground as possible and the electrons running around the edge of the playground. This human model is a little closer to scale, but still far different than the relative distances of an actual atom. In reality, if the nucleus formed by the students on the playground is about two feet wide (or a group hug made up of seven kids), then the electrons in the outside shell should actually be a mile away from the nucleus, not just at the edge of the playground!