Upon further exploration on our Phases of Water Gizmo, students were challenged to answer, How are the phases of water different from one another? Our young scientists were able to explore this question because the Gizmo has a magnifying glass that can be dragged over the beaker so they can see the molecules in each phase.
When students pulled the magnifying glass over the ice, they could see the molecules. They noticed that the molecules were moving very slowly.
In most solid substances, the molecules bond and although they vibrate, they don't move much. The bonded molecules are what gives a solid its fixed shape. Water is a rule breaker in this respect, because the molecules do slow down but they don't bond together as much as most solids. This affects the density of ice.
When the temperature rose, students noticed that the molecules began to move more rapidly. Because ice is a ruler breaker, you can't really tell the difference between ice and liquid water in this Gizmo. Most of the time, you would see the molecules of a solid begin to move more quickly, and become less bonded.When students looked more closely at water vapor, they could clearly see that the molecules began to disperse and move more rapidly. There were very few molecules that could be seen under the magnifying glass because they were dispersed and filled up the entire container.
We added this diagram to our anchor chart.
The way the molecules react to temperature change led us to some very good conversation. The students were able to make the connection that ice and water didn't reach the top of the beaker. The liquid water molecules were loosely fit and can flow past one another. This gives water the ability to pour and its shape changes according to the container that its in. Ice acts differently than most solids because it actually expands when frozen. Have you ever seen a water bottle frozen after putting it in a freezer? Most solids actually shrink when frozen. Water vapor, on the other hand, has molecules that speed up and move apart to fill the whole container.
We discussed that most substances when in solid form have the greatest density and when in gas form are the least dense. The density of a substance refers to how much matter is packed into a particular space or volume. With water, however, ice floats in water. The molecules behave differently. Liquid water is most dense, then ice. Water vapor is the least dense.