Explain that scientists believe all matter, including ice and water, is made of very tiny particles. Single particles of matter are much too small to see even with the most powerful microscopes available. Once enough of the particles clump together, we see them with our eyes as water, or ice, or salt, or other materials. The Particle Magnifier (Water) represents what scientists imagine they might see if they could see individual particles of ice or water at various temperatures.

Start by selecting Absolute zero on the thermometer of the Particle Magnifier (Water) and show the ice/water at increasing temperatures. At each temperature, provide a few words of context (see Notes, below) and ask:

Temp	Notes	Likely student observations
Absolute zero	No heat energy is present.	The particles are arranged in a pattern. The particles are not moving. All of the particles are the same size and shape.
-89°C	The ice is still extremely cold, but heat energy is causing the particles to vibrate.	The particles are still arranged in a pattern. The particles are jiggling, or vibrating. The size of the particles is the same.
-15°C	The ice is warmer, but is still quite frozen.	The particles are vibrating at a greater speed than at -89°C. They are still arranged in a pattern.
2°C	Enough heat energy has been added to transform ice to water.	The particles are no longer arranged in a pattern; they are sliding past and colliding with one another. The water particles look the same as the ice particles.
20°C	The water is at room temperature.	The particles are moving faster, still sliding past and colliding with one another. The water particles look the same as the ice particles.

Temp	Notes	Likely student observations
50°C	The water is now too hot to touch, but it is not boiling.	The particles are moving faster, still sliding past and colliding with one another. The water particles still look the same as the ice particles.

How does the Particle Magnifier explain some of the differences between solids and liquids?

• Solid materials have a shape because the particles are locked together.
• Liquids flow because the particles have more heat energy, have broken away from one another, and can slide past and/or bump one another.