Mixtures & Solutions
Investigation 2
Part 4
Comparing the Crystals
Students examine the crystals left by evaporating the 3 saturated solutions and compare their shapes.
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.
Crystals of specific materials have their own unique structure.
3. Lesson set up and Management
Materials:
You will need the saved trays of the salt, citric acid, and Epsom salt crystals and either a hand lens or loop for each group. If a tray did not get saved do this lesson another time. Make up the solution for the missing crystals, and evaporate it to use for that later time.
Student Management:
This is a very quick lesson. Initially, I have the students draw the crystal pictures in their journals based on their first investigations. Afterwards, I let students look at the saved trays of the three types of crystals to make their comparisons.
Make sure students completely clean all their used trays each time. Otherwise, you will have a mess to clean the next time you wish to use the kit.
Writing Support:
Have the students write a descriptive paragraph comparing the properties of each crystal. This is a good practice in comparing and contrastiing, as well as the use of adjectives.
Reading Support:
There is no specific reading for this lesson.