What is the Best Formula for Flubber?
Lesson 7 of 7
Objective: SWBAT work as chemical engineers to develop criteria for a successful Flubber and create a formula that meets that criteria.
Chemist are responsible for new inventions of all kinds. Chemists are responsible for your hair products, new medicines, food recipes, and toy products such as silly putty and playdough.
Chemical engineers use the engineering design process to create new products. They begin with a request for a new product. The request will include constraints or what materials will be available to use in the new product and criteria for success or how the product will be evaluated.
As chemist we know that there are many recipes for flubber. The design challenge is to find the best possible recipe for flubber. One that scores high on the criteria for success.
Students will notice changes in appearance indicating that a chemical reaction has occurred. Students will observe the liquid glue and borax solution create a precipitate in the form of a non-Newtonian Fluid (having both the properties of liquid and solid) (MS-PS1-2 Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.)
Students will analyze test results to determine the best formula for flubber based on class defined criteria (SP4 Analyzing and Interpreting Data).
Engineers use information gathered by observations of the natural world (science) and apply those skills to develop a better product. When students work as engineers, the constraint will be to use only the ingredients found in a popular formula for flubber. As a class students will define what flubber should be able to do establishing their criteria for success. (MS-ETS1.1 Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.) (SP1 Asking Questions and Defining Problems)
Student engineers will evaluate each of their three formulas to determine which one meets the most criteria for successful flubber. (MS-ETS1.2 Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.) (SP3 Planning and Carrying Out Investigations)
Student engineers will develop and test three formulas for flubber. (MS-ETS1.3 Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.)
An important understanding for students in that engineering is an iterative process. They will design and test solutions three times. (MS-ETS1.4 Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.)
In this short video, I explain why pairing engineering as an extension to a science lesson is good for students.
Here are links to the MSDS (Material Safety Data Sheets) for the materials used in this lesson.
To avoid students putting glue into graduated cylinders, we used clear 9 ounce cups and tape on the scales found in the Resources Section - GraduatedScales9OZCup We disposed of the cups used for glue measurement and made our maintenance staff very happy we were not pouring any little bit of glue down the drain!
A complete materials list is available in the resources section.
Students in Action
The introduction to the lesson begins with this fun little video clip from the movie Flubber. I ask students to pay particular attention to the observations the scientist makes as he describes Flubber.
We are scientists too. We will be making observations about our flubber formulas as well.
What is the engineering design process?
- What is the problem we are trying to solve with this lesson? Problem - we are looking for a new best recipe for flubber.
- What do we already know about flubber formulas? Background - one common recipe found on the internet is 25mL of liquid glue, 25mL of cold water, 25mL of borax solution
- Engineering projects have constraints or limits. What constraints do we have for this lesson? Constraints - chemical engineers must use the same ingredients, however they may change the amount of any ingredient
- Engineering projects also have criteria for success. How should we evaluate a successful formula for flubber? Criteria for Success - the class contributes to a list of criteria for successful flubber. We agree that the flubber should bounce, stretch, be shaped easily, retain that shape and copy print from the newspaper.
The first challenge for the chemical engineer is to make the common recipe found on the internet. This is our standard of comparison.
Engineers then create 3 additional variations of flubber, testing each one to determine its best qualities for presentation in their ad.
I am delighted as I walk around the classroom observing students and listening to discussions about flubber formulas. There is 100% engagement in the classroom.
Connecting the Learning
How do you know a chemical reaction had occurred when you combined the liquid glue and the saturated borax solution? Students should know that a participate was formed when the glob was created.
Which formulas did not perform well according to the class established criteria? When students add little or no water the Flubber does not perform as well.
Why is it important to establish criteria for products? Students should understand that the criteria help us work as impartial judges for what works best.
Even with the established criteria, did your personal bias influence the selection of the best formula?Some students may place value on one criteria over another. They like they way the product bounces or copies print from the newspaper for instance. Some of the student ads reflect their bias for a good product.
Flubber is an example of a polymer. Polymers chain themselves together - they can stretch and bend. How is Flubber like a polymer? Students may remember when the Flubber began to form it stretch into strings.
What are some other examples of polymers? Students may think of things like rubber bands and gum.