Salt Water Ice Activity For Teachers

The goal of this experiment is to explore the differences between freshwater ice and sea ice. This experiment allows the students to make observations about the two types of ice.

Tips for Classroom Implementation

Time Required: Two 50-minute class periods on two different days (one to prepare and freeze the ice cores, the other to add food coloring and observe its movement through or around the ice).

Tips:

• Read Frozen Life companion story as a class before beginning this activity. It will teach students about brine channels in sea ice and the importance of plankton in arctic ecosystems.
• Place a container under the ice to collect water as it melts.

Extensions

• Conduct experiment with many different concentrations of salt to see how the dispersion differs between ice samples.
• Research and observe how long it takes for water with different concentration of salt to freeze. At 32˚F (0˚C) the fresh water will freeze but with salt water it will not freeze at this temperature.
• Research and observe the effects of temperature on ice. Have students touch both types of ice (before adding food coloring) and see if they can feel a difference. The salt water ice will feel colder because when salt is added to water it lowers the freezing point. Water will continue to get colder until it reaches its freezing point (depending on the salt concentration, typical sea water at 34ppt salinity would freeze at 28.65˚F (-1.86˚C)) so it will be colder than fresh water.

Objective

• Students will compare and contrast the differences between sea and freshwater ice.

Arizona Science Standards

Arizona Science Standards

Strand 1: Inquiry Process

Concept 1: Observations, Questions, and Hypotheses
K-4: Observe, ask questions, and make predictions.

Concept 2: Scientific Testing (Investigating and Modeling)
K-4: Participate in planning and conducting investigations, and recording data.

Strand 4: Life Science

Concept 3: Organisms and Environments
K-4: Understand the relationships among various organisms and their environment.

Common Core Standards:

6-8.RST.3 Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks.

Next Generation Standards:

5-LS2-1. Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment. (For this one, have students walk through the food webs in the Frozen Life companion story.)

Additional image from Wikimedia via Patrick Kelley.