Mixtures & Solutions
Investigation 1
Part 3
Observing Crystals
Students observe the crystals left after the water from the salt solution has evaporated. Review the states of matter. What happened to the water? Do all solids have a specific shape?
3. Lesson set up and Management
Properties of Substances (PR01 1.1.1)
• Use properties to sort natural and manufactured materials and objects, for example, size, weight, shape, color, texture, and hardness. Grades K, 1, 2, 3, 4, & 5.
• Use physical and chemical properties to identify and describe substances; for example: density, boiling point, and solubility. Grades 6, 7, & 8.
Changes in Systems (CH01 1.3.3)
• Know that matter can undergo changes of state such as evaporation, condensation, or freezing and thawing. Grades K, 1, 2, 3, 4, & 5.
• Understand physical and chemical changes at the particle level and know that matter is conserved. Grades 6, 7, & 8.
• Solid material separated by evaporation from a solution forms distinctive patterns.
• Matter in its solid form has a distinctive structure.
• Matter is conserved.
3. Lesson set up and Management
Materials:
Hand lenses
• Should be in the Foss measurement kit
• Loops also work fine for this
• Microscopes are not needed
Instead of duplicating the journal page in the manual, have students use a spiral notebook to write prompts.
Student Management:
Hand out the evaporation trays to one member of each group. Letting the students get them can cause confusion and mix ups. When the groups have their trays, begin with the questions at the start of the investigation.
Have the questions from the start of the investigation written on the overhead or board. Have students record what they think the answers are in their journal before the class discussion. This is a great assessment opportunity as you circulate to evaluate individual understandings of the concepts. You can also have the students draw a picture of their observations for comparisons to be made later on. It is important for students to review the procedures and record what they did in their journals.
Be sure to save two of the evaporation trays containing salt crystals. These will be used in Investigation 2, Part 4.
Writing Support:
Have the students do the writing above as well as the word bank entries and the inquiry entries.
Reading Support:
After reading “A Salty Story” in the Mixtures and Solutions: Science Stories book, have students discuss a fact they learned and why salt is such an important compound.