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How to Make a Model of a Solid, Liquid and Gas From Styrofoam

Learning about the elements of the world can be a lot of fun, but it's difficult to view everything that's really happening inside these elements unless you're using a powerful microscope. If you're entering a science fair, or you just want to illustrate how solids, liquids and gases are formed, you can use regular polystyrene balls to put together quite a display, using a basic planetary model. This method was created when the atomic nucleus was first discovered, and is still widely taught to children today.

Things You'll Need

Calculator
Polystyrene balls
Magic markers
Three colors of model paint (optional)
Model glue
Wood glue
Long piece of wire
Pipe cleaners (optional)
Posterboard

Instructions

- 1
  
  A periodic table will usually tell you the atomic number and weight of the element.
  
  Look at an accurate periodic table of the 118 known elements and choose a solid, liquid and gas you'd like to represent with the polystyrene balls. The periodic table will be helpful for a few reasons. It will likely tell you whether the element is in a solid, liquid or gas phase at normal room temperature; the atomic weight of the element; and the number of electrons it contains. A good reference is the Jefferson Lab Periodic Table (see the Reference section), where you can learn everything about the elements you select for your experiment.
- 2
  
  The atomic number of gold, or Au, (seen on the right) is 79.
  
  Calculate the number of protons and electrons in your elements. Finding the electrons is easy, since the atomic number of the element denotes the amount of electrons it has. For example, the atomic number for gold (Au), which is a solid, is 79. Therefore, there are 79 electrons in one atom of gold. Every atom must have an equal number of protons to balance the electrons, so in the above example, gold has 79 protons as well.
- 3
  Calculate the number of neutrons in your elements by looking at the total atomic weight of the solid, liquid or gas. The number of neutrons equals the atomic weight rounded up to the nearest whole number, and subtracting the number of protons and electrons. For the gold example, the atomic weight is 196.966569. Round this number up to 197, then subtract the number of electrons (79) and protons (79), and you'll see there are 39 neutrons in one atom of gold.
- 4
  Construct the nucleus of your atom first, by holding each of your polystyrene balls and labeling them as protons and neutrons -- either marking them with letters or numbers, or painting them by hand -- and adding the positive sign on each proton to show its charge. The nucleus is the center of an atom, where all the protons and neutrons are bunched together. You can accurately illustrate this formation by taking model glue, dabbing a bit onto each of the balls and sticking them together to form a base.
- 5
  Construct the electron representation which will be outside of the base of protons and neutrons. The easiest way is to take a long piece of wire, or several pipe cleaners, and shape them into a circle. Mark each of your polystyrene balls for this part of the model with a different kind of paint, or leave them uncolored, with just a negative symbol on each to show the charge. Glue these balls in various places on the ring you created.
- 6
  Paste the proton and neutron base, along with the ring of electrons, onto a large piece of posterboard with wood glue. Repeat steps 2 through 6 for each of your elements, marking your posterboard for each with proper labels, and you'll have a scientific and fun representation of the atoms contained in a solid, liquid or gas.

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