Polymer Strand Vanderbilt Student Volunteers for Science Training Presentation Spring, 2007

Important! Please use this resource to reinforce your understanding of the lesson! Make sure you have read and understand the entire lesson prior to picking up the kit! We recommend that you work through the kit with your team prior to going into the classroom. This presentation does not contain the entire lesson—only selected experiments that may be difficult to visualize and/or understand.

Set-Up One VSVS member should take the container of calcium chloride solution and half fill 34 1-oz cups while other members are handing out the materials listed below. Give each student –One paper towel sheet –One 1-oz cup half-filled with calcium chloride solution –One small plastic spoon –One observation sheet Pass out one dropper bottle of sodium alginate to each pair Tell students they will be sharing a dropper bottle with another student

Step 1 One VSVS member should demonstrate the following technique that each student will be using to get beads of polymer gel. Take the red cap off the dropper bottle and while holding the bottle over the 1 oz cup of calcium chloride solution placed on the paper towel, carefully squeeze 4 drops of sodium alginate into the 1 oz cup. Use a small spoon to take the blue gel beads out of the calcium chloride and lay them on the paper towel.

Step 2 Then, add a squirt of sodium alginate into the 1 oz cup of calcium chloride. Use the small spoon to take the blue polymer strand out of the calcium chloride and lay it on the paper towel. (Tell them that blue food dye has been added to the sodium alginate solution to make the polymer strands easier to see.) Let each student make their own polymer beads and strand and have take them out of the cup and put on the paper towel.

Step 3 Then, tell each student to make another set of polymer beads by carefully squeezing out 4 drops of sodium alginate into the 1 oz cup and leave it in the solution for five minutes. During the five minutes you are waiting, tell the students to use the small spoon and press down on one of the polymer beads they put on the paper towel from the first part of the experiment. Ask them to record their observations on the observation sheet. (The drops smash easily because the inside of the polymer beads is liquid.)

Step 3 Cont. When the 5 minutes is up, tell the students to remove the polymer beads from the solution. They should use the small spoon to press down on one of the 5-minute polymer beads. Ask them to record their observations and to compare the results with the polymer bead they prepared earlier. (They shouldn’t smash as easily as the other gel beads. This is because more cross-linking has occurred.)

Clean-Up Then let each student make a polymer strand following the same technique. Tell the students to keep their polymer strands and small spheres on the paper towel until the next day to observe what happens, if anything. Clean-up: Students may keep the paper towel sheet with their polymer strands. Empty the 1-oz cups down the drain. Put used plastic cups and spoons in the plastic trash bag. Make sure all red caps are on the dropper bottles. Return dropper bottles and the container of calcium chloride to the box. Place the trash bag in the box and bring the box back to VSVS lab as soon as possible.