
The goal of this demonstration is to show how Gore-tex can allow some things through but keeps others out. Specifically letting through gases but keeping water or other liquids out.
The goal of this demonstration is to show how Gore-tex can allow some things through but keeps others out. Specifically letting through gases but keeping water or other liquids out.
Materials needed:
- Micro scale: 2 Gore-tex gloves
- 1 Plastic glove
- 3 squeeze bottles with cotton balls with scented oils inside
- Water
- Macro-scale: Frame with ribbon cross hatching
- Ping-Pong balls with Velcro dots
Procedure
Set-up:
- Velcro one plastic and one Gore-tex glove on to one bottle each.
- Fill third bottle with small amount of water and then attach Gore-tex glove.
- Lay out "water molecules" stuck together to form a "water drop".
Supplies to have out:
- 1 red squeeze bottle with Gortex glove
- 1 yellow squeeze bottle with plastic glove
- 1 squeeze bottle with water inside and Gortex glove
- Frame with water molecules
During the Demonstration:
- Let visitors feel both gloves, then ask them what they notice. Have the visitors squeeze the bottles to smell each one. (Be careful not to squeeze too much - then the whole room smells and you don't know where the smell is coming from.) Ask them what each bottle smells like. Probe for discussion by asking how smell travels.
- Then show the visitor the water bottle. Ask them if they think water will go through the glove. Let them try it out and see what happens.
- Have a visitor hold the frame. Show them one ball and one clump of balls. Ask them if they know which one is gas and which is a water droplet. You can give them a hint by asking which they can see better a water droplet or the moisture in the air? The gas is harder to see because it's smaller. Drop the "gas" molecule onto the frame, then drop the "water" molecule onto the frame. Tell the visitors that this frame is like Gore-tex because it lets single molecules like air through and not large clumps of molecules like water droplets.
Cleanup:
- Remove Gore-tex glove from bottle and empty water.
- Gather all materials and return to storage.
Explanation:
Just like the frame, the size of the holes between fibers of Gore-tex lets single molecules, like air, through and not large clumps of molecules, like water droplets. Often Gore-tex also has a water repellent on it. This also causes the water to bead up and become larger droplets that won't fit through.
What Could Go Wrong?
Be careful not to squeeze the scented bottle too much - then the whole room smells and you don't know where the smell is coming from.
General Maintenance:
Because you are using water you could get mildew growing on things. Try to dry everything before you put it away. Check for mildew every few weeks and wash with warm soapy water or replace the materials if this is an issue.
Procedure Sheet: goretex_procedure.pdf
Gore-Tex FAQs
The Gore-Tex® demonstration shows the properties of how a microporous material can allow only molecules of a certain size to pass through.
Cool Facts:
- If you own a raincoat or any waterproof sports clothing, they most likely have Gore-Tex® in/on them.
- Gore-Tex® gloves don't make you sweat! They allow for enough air to pass through in order to keep sweat from accumulating on your hands by allowing the sweat to evaporate.
- Gore-Tex® has also been used in dental floss because it can slide between teeth that regular dental floss can't!
- Gore-Tex® can be used as a body implant material for cosmetic surgery. It is safe to use in the body because it is a material that does not react with body tissues.
A Gore-Tex® is actually a microporous material, discovered in 1969 by stretching PTFE (polytetrafluoroethylene) otherwise known as Teflon.
A: Fabrics are materials that are made by weaving threads together in a pattern. Examples are cotton and linen.
A: Gore-Tex® is a porous material, but not a fabric. It is similar in that it allows air to pass through it, but the pores are small enough that water molecules cannot pass through because of their size. This makes it seem like a very tightly woven fabric.
A: One glove is made out of plastic and doesn’t have any pores which the air or water can pass through. The Gore-Tex® glove is made out of a completely different type of material.
A: Because of its ability to allow air molecules to pass through, Gore-Tex® would not work well in garbage bags because the odors would escape the bag.
The outermost layer of many articles of sporting attire is now made out of Gore-Tex®. Because of its combined waterproof and breathable nature, it is a popular and useful choice in clothing. ‘Warm-up’ suits and raincoats are often made of this material. Elixer® guitar strings are popular due to their longevity and are also made of Gore-Tex®.