The Three Basic States (Phases) of Matter

Target Subject: Physical Science

Purpose

To introduce the three states of matter, by examining tactile models illustrating the characteristics of particles in each state.

Background information

It is hard to imagine that matter is made of particles since no one can see them. In print textbooks, the diagrams used to demonstrate the phases of matter frequently look like round balls or marbles. The particles in a solid are shown in a grid with the particles very close together. In the picture representing a liquid, the balls have more space between each one, and for gases the balls are drawn with even more space between them. Sometimes the drawing includes arrows representing the movement of the particles. In this activity, marbles and balloons model the particles and their movement.

Preparation

To create models for the particles of a solid, liquid and gas, use three plastic plates and about 50 marbles for each student. Label the first plate “SOLID” and fill the plate with marbles until there is no room left between them to move. Label the second plate “LIQUID” and fill the plate with fewer marbles than the solid, leaving room for the marbles to roll around a bit. Label the third plate “GAS” and add around 5 marbles, giving them room to move freely.

Another demonstration model uses balloons and large trash bags. Blow up several balloons and pack them into a large trash bag until the bag is full and the balloons do not move around when touched to model a solid. To model a liquid fill the bag so that the balloons can move around freely and the bag can change shape. To create a model of a gas, put in only a few balloons and fill the rest of the bag with air to represent the space. (This activity may be difficult for students who are easily startled by popping of balloons that may occur accidentally.)

Materials

• 3 plastic plates for each student
• Approximately 50 marbles
• Braille and large print marbles
• Round balloons, filled with air
• Large clear plastic bags
• Tactile diagrams of solid, liquid and gas particles.

Procedure

1. Examine the relative space between the marbles on the three different plates starting with the solid.
2. Notice the ability of the marbles to move in the available space in each model.
3. Next examine all three bags of balloons.
4. Observe that the shape of a solid stays constant. There is not much room between the particles so they aren’t able to move.
5. Examine the bag representing a liquid. Note how the particles have more room to move around, so the bag can be shifted into different shapes much like a liquid can take the shape of its container. This can be demonstrated by putting the bag into a square box or round trash barrel.
6. Examine the bag representing the gas, the balloons will move around freely and can be felt bumping against the side of the bag.
7. Examine raised line drawings of the three states or phases of matter that correspond to the drawings in the print text. Textbooks available in Braille may have excellent diagrams. The states of matter are also illustrated as round particles in Basic Science Tactile Graphics published by the American Printing House for the Blind.