Atomic Nucleus

Physics

Atoms, Parts of the Atom

Grade Range

Middle School, High School

Format

Hands-on

Materials

• Velcro atom
• Million dot book (optional)
• Velcro electrons (optional)

Safety Precautions

Please see the Other Demonstration Hazards and Safety Precautions section on the Demonstration Safety page.

Demonstration

Preparation: Make sure the velcro atom is disassembled before beginning the demonstration.

1. Show the two parts of the velcro atom to the students, identifying the protons and neutrons. (Optional) Include the electrons.
2. (Optional) Show the million dot book, and explain what the size of an atom actually is.
3. Have the students try to assemble an atom with just the neutrons. When they show they cannot, explain why.
4. Have the students start building an atom with the protons and neutrons. (Optional) Have them add electrons in for each proton they put in.

Why This Works

The atom is composed of protons, neutrons and electrons. These particles are all very tiny, on the scale of nanometers. To give an idea of how small a nanometer is, we have a million dot book. Each dot is only one millionth of the book, which means each dot is pretty small. If we split each dot into a thousand more dots, then each of those dots would be one billionth of the book! A nanometer is one billionth of a meter, which is really, really small!

The number of protons in an atom determines what element that atom is. If we use only one proton, that would be hydrogen. If we use six, that makes it carbon. However, it is really hard to get six protons to stick together, because protons have a positive charge, and like charges repel. That's where neutrons come into play; they have a neutral charge, so they can connect to protons. They help to keep those protons together for bigger elements. We can adjust the number of neutrons that are in an element, which changes how the element interacts with other elements. Each type of an element with a different number of neutrons is known as an isotope, and some isotopes are more stable than others. For example, Carbon-12 is stable, and is the carbon we usually see, with six protons and six neutrons. Carbon-13 has one extra neutron, and is what we use for Carbon Dating, a method to figure out how old something is!

Electrons are smaller than protons and neutrons, and are not in the atom itself. They have a negative charge, and float around the atom because of the positive charge on the protons. If an atom has a charge to it, we call it an ion. If it lacks electrons, it has a positive charge, and is called a cation. If it has extra electrons, it has a negative charge, and is called an anion.

Additional Information

• This demonstration is a part of the Nuclear Physics Show.