How to Turn Homemade Salt Crystals into Sparkly Apples!

Instructions

1. Here is the homemade salt crystal STEM lesson plan.

Objective

2. Students will understand the science behind the formation of salt crystals and will be able to create salt crystals in the shape of apples using a hands-on experiment.

Duration

Two 45-minute class periods 3-4 days apart.

Materials

• Table salt (NaCl)
• Hot water
• Clear glass jars
• Measuring spoons and cups
• String
• Pencils
• Pipe cleaners (red, green, brown, and yellow)
• Magnifying glasses
• Science journals

Day 1 - Introduction and Experiment Set-Up

Do these activities on day 1.

1. Introduction to Salt Crystals (15 minutes)

• Begin with a discussion on what students know about salt crystals.

• Show them examples of natural salt crystals and explain their formation.

• Explain the process of crystallization. Talk about how, when a saturated salt solution starts cooling or evaporating, salt molecules begin to settle out and organize themselves in a crystalline structure.

3. Hands-on Experiment Set-up (20 minutes)

• Instruct students to add several tablespoons of table salt to a container.

• Pour in hot water (about a cup) and stir until the salt stops dissolving. If all the salt dissolves, add more until you have some undissolved salt at the bottom. This ensures your solution is fully saturated.

• Shape the apples from pipe cleaners while the supersaturated solution cools.

• Add a stem and leaf to each apple.

• Tie a string to the top of each apple and wrap it around the center of a clothespin.

• Lay the clothespin over the opening of the jar, ensuring the apple doesn't touch any sides of the jar.

• Pour the cooled supersaturated solution into the jar, covering the apple.

4. Making Predictions (10 minutes)

• Have students to write in their science journals or STEM worksheets what they predict will happen to the apples over the next few days.

Day 2 - Observation and Analysis

Here is what to do the next class period, 3-4 days later.

1. Observing the Results (15 minutes)

• After a few days, the solution should start forming crystals around the string and within the apple mold.

• Remove the apples from the jars and let dry on a paper towel.

• Instruct students to observe their apple-shaped salt crystals using magnifying glasses.

2. Discussing the Results (20 minutes)

• Discuss the results with the class. Were their predictions correct? Why or why not?

• Talk about how the shape of the apple was formed and how the salt molecules attached themselves to the pipe cleaners.

3. Writing and Reflection (10 minutes)

• Have students write their observations on their STEM worksheet, including drawings of their apple-shaped salt crystals.

Assessment:

• Participation in the discussion and hands-on experiment.

• Predictions and observations recorded in science journals.

• Full understanding of the concept of how and why salt crystals form.