Each group needs:

• a thermometer OR a LEGO MINDSTORMS EV3 Intelligent Brick with an attached LEGO MINDSTORMS Temperature Sensor (the EV3 Intelligent Brick at https://education.lego.com/en-us/products/lego-mindstorms-education-ev3-intelligent-brick/45500); the MINDSTORMS temperature sensor at https://education.lego.com/en-us/products/lego-mindstorms-education-ev3-temperature-sensor/9749
• 1 gallon-size plastic bag
• ice cubes, enough so the gallon-size plastic bag is about one-quarter filled
• one-quarter cup ice cream mix placed in a 1 quart-sized Ziploc® bag (see below for ingredients to make the ice cream mix )
• wooden stirring spoon
• paper towel
• paper and pencil
• watch or stopwatch, to measure two-minute intervals (or use classroom wall clock)
• plastic spoon, one per student
• 12 Dixie cups, three per student

In addition, prepare the following supplies for the three different group types:

• give the "no salt" groups nothing extra
• give the "some salt" groups each a plastic baggie containing one-quarter cup salt
• give the "lots of salt" groups each a plastic baggie containing 1.5 cup salt (or more)

To make the ice-cream mix (makes 17 single-bag [¼ cup] servings):

• 2 cups half & half
• 2 cups heavy cream
• ¼ cup powdered sugar
• 1 teaspoon vanilla extract

To share with the entire class:

• classroom board or overhead projector

Alternative: LEGO MINDSTORMS NXT Set:

Note: This activity can also be conducted with the older (and no longer sold) LEGO MINDSTORMS NXT set instead of EV3; see below for those supplies:

• a thermometer OR a LEGO MINDSTORMS NXT Intelligent Brick with an attached LEGO NXT Temperature Sensor
• computer loaded with the NXT 2.1 software