Gackety-Gak
This Stuff Bounces Back
Topics: Matter, Chemical
Changes, Polymers
Materials List
 White glue
 Sodium Tetraborate
(Borax) (Na2B4O7)
 Water
 Lab equipment to
measure volume
and transfer liquids
(beakers, graduated
cylinders, graduated
syringes)
 Craft sticks
 Small, zipper-close
baggie
This activity can be used
to teach:
Next Generation Science
Standards:
 Structure of matter
(Grade 5, Physical
Science 1-1)
 Properties of materials
(Grade 5, Physical
Science 1-3)
 Changes of state
(Middle School,
Physical Science 1-4)
 Chemical reactions
(Middle School,
Physical Science 1-2)
 Mixtures (Grade 5,
Physical Science 1-4)
Written by Coral Clark (RAFT)
Slimes and putties, like Gackety-Gak, are great student hooks to teach polymers,
physical and chemical properties, and organic chemistry. Kids just love it!
To Do and Notice
1. Prepare the borax solution by dissolving 30 ml (2 Tablespoons) borax in 500 ml
(~2 cups) hot water. (Safety note: instructors should do this step if student
skill/age level poses a safety concern.) (Teacher note: test the solution before
class to make sure that the strength is adequate.)
*Borax is commonly marketed as a laundry additive and sold in grocery stores in
the laundry detergent section.
2. Measure 10 ml (2 teaspoons) borax solution into a zipper-lock bag.
3. Mix 15 ml (1 Tablespoon) white glue and 15 ml (1 Tablespoon) of water together
using the craft stick.
4. Pour the diluted glue mixture into the baggie with borax solution.
5. Squish the mixture together to see the polymer putty form. Remove the putty
from the baggie and knead it a little to thoroughly mix in any remaining water.
6. Notice that if pulled quickly, the putty will break. If pulled slowly, the putty will
run. What other properties does the putty exhibit?
The Science Behind the Activity
Polymers are long-chain molecules of repeating smaller units (monomers). In this
putty, white glue is mixed with borax to create a network of weak-linked polymer
molecules that trap water. The putty can be formed into shapes like a solid, but also
flows like a liquid. It is considered a rheopectic, non-Newtonian fluid.
Silly Putty brand putty was introduced to the public as a plaything in March of 1950,
6 years after GE engineers were attempting to create a synthetic rubber from a
silicone oil and boric acid. No one at the company could figure out anything practical
to do with the putty, but then Peter Hodgson of Connecticut put the putty in a plastic
egg and marketed it as a toy. A new era for toys was born… or could we say
hatched?
Web Resources (Visit www.raft.net/raft-idea?isid=72 for more resources!)
For more information on the mineral borax, go to: http://www.galleries.com/Borax
Copyright 2015, RAFT