How to Make an Atom Structure at Home With Marshmallows

Atoms were once believed to be the smallest objects in existence.

In 1911, the Nobel Prize-winning chemist Ernest Rutherford became aware that atoms contained elements called protons and neutrons. Rutherford then discovered that electrons orbited the protons and neutrons, but the geometry of atoms was still open to debate. A Danish scientist, Niels Bohr, then suggested that electrons revolved around the nucleus in several different orbits. Although the model suggested by Bohr is no longer considered perfect, it is still the best model to demonstrate the structure of an atom.

Things You'll Need

• Packet of large multicolored marshmallows
• Packet of small marshmallows
• Large paper plate

Instructions

1. Place three large white marshmallows and four large pink marshmallows in a group in the center of a large plate. These represent three protons and four neutrons in the nucleus of a lithium atom.

2. Place a small marshmallow on the outer edge of the plate. It can go anywhere around the edge because it represents a second-energy-level electron orbiting the lithium nucleus.

3. Place two small marshmallows in an orbiting position about halfway between the nucleus and the edge of the plate. These represent two lithium electrons in the first-energy-level orbit. The model of the atomic structure of an atom is complete.

Tips & Warnings

• The atom you've created is lithium, the metal used in mobile-phone batteries.

• Try a more complicated atom, such as meitnerium, with 109 protons, 157 neutrons and 109 electrons. Take turns to remove neutrons, protons and electrons to make smaller atoms and then eat the unwanted particles!

• The Bohr atom model is a good representation of atomic structure to introduce the particles, but it simplifies the situation. Electrons don't seem to exist in any one place but are more like a smear or a blur in orbit around the nucleus.

• The difference in size between protons, neutrons and electrons and between large and small marshmallows is not to scale.

References

• Indiana University Northwest; Rutherford's Planetary Model of the Atom; N. De Leon
• University of Tennessee Dept. Physics & Astronomy: The Bohr Model
• Chemical Elements.Com: Periodic Table - Lithium
• Georgia State University Hyperphysics; Lithium Energy Levels; C.R.Nave; 2011
• Chemical Elements.Com:Periodic Table - Meitnerium