Our Water theme started last week with experiments on the physical properties of water. At different levels and in different groups, students have explored what floats and what does not; dwelt on the concept of density and buoyancy; experimented with water pressure and communicating vases; built gravity-driven flows and boats to float on them; and experimented with watercolor painting. This week they continue with experiments on the physical properties of water and start looking at its chemical properties. They will explore how water changes state from ice to liquid to vapor, and measure the temperature as they cool or warm water. They will observe ice cubes floating on water and ponder over whether or not melting icebergs will contribute to sea level rise. They will explore the structure of snow flakes and experiment with solutions and diffusion.
These first two weeks address Next Generation Science Standards, including:
- Collaborate with a partner to collect information.
- Keep records as appropriate—such as pictorial records—of investigations conducted.
- Recognize that learning can come from careful observation.
- Sort objects by observable properties, such as size, shape, color, temperature (hot or cold), weight (heavy or light) and texture, and whether objects sink or float.
- Raise questions about the natural world, investigate them in teams through free exploration, and generate appropriate explanations based on those explorations.
- Observe and measure objects in terms of their properties, including size, shape, color, temperature, weight, texture, sinking or floating in water.
- Observe and describe water in its solid, liquid, and gaseous states.
- Identify properties and common uses of water in each of its states.
- Describe how moving water and air are sources of energy and can be used to move things.
- Investigate and identify materials that will dissolve in water and those that will not and identify the conditions that will speed up or slow down the dissolving process.
The big ideas we are insisting on are: Water (as a liquid) has no shape; it adopts the shape of the container that holds it. Whenever an object is introduced into a container of water, water is "displaced." There is a difference between "sitting on the water" (supported by surface tension) and "floating" on the water; in the first case, gently pushing the object down sends it to the bottom, in the second case, the objects bobs back up. Ice floats because it is less dense than water. Water (a.k.a. the "universal solvent") is very good at dissolving other substances.