# Water Permeability

To conduct this experiment, I used a bioplastic bag constructed from Ag12, and the process was described in the post "Heat Joining Bioplastic". The bag was grasped by soldering "helping hands", which are like alligator clips on a metal rod, though other instruments would probably serve this purpose better. Then, I injected 10 mL of water into the bag with the help of a syringe.

My setup:

![](https://829019481-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FQKxP3dLVX23EmnpaB5PS%2Fuploads%2FnCP4h6TkYxSFLgss6Zq9%2FIMG_2380.jpeg?alt=media\&token=e5a0ee16-b877-43a5-bdb8-9287cb08fc70)

The results:

The bag could hold water for a few hours (approx. 4) before water ended up on the newspaper. I couldn't tell if this was because water was actually traveling through the bioplastic, or if I joined the bioplastic poorly, but either way, it seems like I will redo the test.

An interesting thing I found is that the part of the bag that was holding the bioplastic actually started to biodegrade (or something else) a bit because it shrank and became rigid and hard, while the bioplastic that was not directly touching water didn't. By biodegrade, I mean that the glycerol started to leach out with the help of the water (I think). I think this for two reasons: (1 a sticky substance was found in the water that came through the bioplastic and (2 glycerol acts as a plasticizer which keeps things flexible, and the part touching the water lost its flexibility.

Before photo:

![](https://829019481-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FQKxP3dLVX23EmnpaB5PS%2Fuploads%2FF3YWk0W37HxtjbWHKmDd%2FIMG_2375.jpeg?alt=media\&token=f8284b46-adb1-4202-9237-b346c384e72f)

After photo:

![](https://829019481-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FQKxP3dLVX23EmnpaB5PS%2Fuploads%2Fh9Qq8hrFvzM7VdhJhi0J%2FIMG_2403.jpeg?alt=media\&token=f6acff56-c991-4761-8f97-66dbafbb39b2)

Testing photo:

![](https://829019481-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FQKxP3dLVX23EmnpaB5PS%2Fuploads%2FmsVi8KXtEQUyGDp1uUoa%2FIMG_2381.jpeg?alt=media\&token=994c8f72-d0fc-43c1-8f8e-a4b7316dee3e)

Notice the meniscus there. A meniscus forms when the material has a charge because water is polar and wants to stick to stuff that has a charge. So, this means the bioplastic has a charge.