To begin the lesson, I work with students to define the characteristics of liquids. We discuss that liquids conform to the shape of their container. I provide students with a chance to speak with their peers about their experiences with liquids that are familiar to them to help them make personal connections to the material they are learning. I then inform students that water is a special liquid because it has unique properties. I tell students that in their lab work they will explore one of the unique properties that makes water such a special liquid.
Background information of the unique properties of water can be found here.
I distribute a copy of the surface tension lab to each student. I explain that in the day's lab, the students will be adding drops of water to a penny using an eye dropper. I show students the water dropper tray that I prepared for each group and name each piece of equipment. I then review the question that we will answer in the lab and ask students to make a prediction about how many drops of water they think their penny will be able to hold. After each student has made their prediction, I go over the procedures for the lab and review the data that each student will need to collect.
A video of my students completing one test in this lab can be found here.
To conclude the lab, I ask students to do two separate activities. First, I ask students to use the data table on the back side of their lab sheet to draw conclusions about the lab they conducted. Students use the data collected in their data table to discuss which side of the penny held more water, the effects of soap and salt on the water, and to make a guess as to why this happened.
I then define for students two of the special properties of water that are responsible for the action of the water on the penny in the lab: cohesion and surface tension. We discuss the definition for each term and add the terms to our pocket chart containing the vocabulary words for the unit. This pocket chart serves as a visual reminder for students of they content they have learned throughout the unit.