Valerie Andrews- Investigating Colloid Polymers
Title: Investigating Colloid Polymers (Flubber)
Principle(s) Investigated:
(reviewed)-What is a solid ? (A solid is rigid, and retains its shape. It has a set shape and volume.)
(reviewed)-What is a liquid ? (A liquid is fluid, has definite volume, and will take the shape of its container.)
-What is a mixture ? (two different types of molecules that are currently blended, but could be separated)
What is a colloid ? (A colloid is made of particles which will not settle out of a mixture. Colloids have some properties of solids, and some of liquids.)
-What is a polymer ? (A polymer is a long chain of molecules that look something like strings of cooked spaghetti. Polymers can slide past each other, and it will act like a liquid. If they hook together, then it will have the properties of a solid.)
Eighth Grade: Structure of Matter
3. c. Students know atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.
d. Students know the states of matter (solid, liquid, gas) depend on molecular motion.
e. Students know that in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently.
Materials:
All supplies can be obtained from a grocery store, or Target:
To make the Flubber:
Borax Mixture:
-2 tsp Borax
-1 1/3 cups of hot water (not boiling)
Glue Mixture:
-2 large bottles of Elmer‘s glue (8oz bottles)
-1 ½ cups of hot water (not boiling)
During the inquiry lesson, students will also need:
-a plastic cup
-a rubber ball or marble
-newspaper to cover the desks
Procedure:
Mix the Borax mixture in one bowl thoroughly.
Mix the glue mixture in another bowl thoroughly.
Then combine the two by adding the hot Borax mix to the hot glue mix.
Mix this well and let it sit for 2-3 minutes while it solidifies and cools.
Student prior knowledge:
Before this activity is done, your students should have already investigated the concepts of solids and liquids. This lesson will challenge their thinking because the students are asked to evaluate whether the Flubber is a liquid or a solid based the tests that they do, and the prior knowledge that they have.
Explanation:
-Review what you know about solids, liquids, and gasses. Fill out the chart on the board / projector about the different characteristics of each:
-Inform the students that today we are going to look at a substance, and decide which state of matter it is.
-You may want to have your students work in small groups or pairs, so that they can elaborate on what they see using scientific discussion questions.
-Distribute the observation sheet to each student. Read through the questions together so that there is no question about what is expected.
-Have one person from each group come up and get their Flubber. One other person will need to come up and get the other materials.
-Allow the students to investigate the Flubber, they need to record their observations on the observation sheet.
- Call for a poll of the students to see who thinks it’s a liquid and who thinks it is a solid. Ask some students to explain their thinking.
- Show the students how the Flubber was created.
-You need to mix the hot Borax mixture into the hot glue mixture. Mix it for a few minutes and then let it sit. While the mix is forming the Flubber, discuss the following points with your students:
-The Borax is a mixture because it does not dissolve into the water. It can be separated. When the two mixtures combine a Polymer colloid is formed.
-A colloid is a mixture where the particles are too large to dissolve, but small enough to remain suspended in the liquid. A polymer is a long chain of molecules that looks kind of like cooked spaghetti. In a polymer colloid, the suspended particles are long polymer strands.
-If the polymer chains slide past one another easily then the substance acts like a liquid. If the molecules hook together, then they form a more rubbery-solid. In the Flubber, Borax is what hooks the glues polymer molecules together.
Closure:
-Ask students to think of real life examples of other substances that have both solid and liquid characteristics.
Questions & Answers:
In what ways is the Flubber similar to a liquid?
-If you put it into a container, it will take the shape of the container.
In what ways is the Flubber similar to a solid?
-If you roll it into a ball, it will bounce, and hold its shape.
How would you classify Flubber?
-Students will come up with a wide variety of answers to this question. The important part is WHY they classify it as a specific state of matter. The correct answer is a polymer colloid.
What other substances have you seen that behave similarly to the Flubber?
One example could be Jell-o.
Is a colloid a state of matter?
No. Matter is either a solid, liquid, or a gas. There is one other option which is a plasma. A colloid is just a substance that is a mixture and so it behaves like both.
Applications to Everyday Life:
Below is a list of everyday polymers:
CoolWhip®
Pudding/desserts/cake
Astroturf®
Boots
Velcro®
Basketball
iPod®
Panty hose
Roller blades
Fishing rod
Watch
Credit card
Frozen foods
Jelly/jam
Dish pan
Stereo
Thermos
Tennis ball
Air freshener
Artificial flowers
Salad dressing
Bubble gum
Tennis racquet
Contact lenses
Wet suit
Football pads
Chair/table
Swim fins
Frisbee®
Paint
Shin guards
Balloons
Eye glasses
Raincoat/windbreaker
Carpeting
Teflon®
cookware
Hair spray
Sunscreen
Snorkel
Nerf®
Umbrella
Disposable diapers
Telephone
Straws
Silly Putty®
Tape
Cosmetics
Gravy
glue
CDs
Computer
Automobile
Bicycle
Shoe strings
Tennis shoes
Plastic fork/spoon Shampoo
Insulated cups
2 liter soda bottle
Plastic bags
Pen
Scotch® tape
There are many different types of colloids:
Sources:
"Kids Science Information on Polymers and States of Matter." Science Kids at Home -. 2011. Web. 12 Apr. 2011. <http://www.sciencekidsathome.com/science_topics/amazing-polymers.html>.
VanCleave., Janice. "Gak Recipe - A to Z Home's Cool Homeschooling." A to Z Homeschool Curriculum, Laws, Programs, Social Networks. 2011. Web. 12 Apr. 2011. <http://homeschooling.gomilpitas.com/extras/Gak.htm>.