prompter: I am building a bubble light and I need something to put at the bottom of the tube to provoke bubble nucleation.  Can you suggest a material that is heavy enough to stay at the bottom of the tube, insoluble in dichloromethane, and porous enough to be a good place for bubbles to form?

assistant: One material that could potentially work for provoking bubble nucleation in a bubble light is silicon carbide (SiC) powder. SiC powder is a highly porous material that is insoluble in many solvents, including dichloromethane. It is also relatively heavy and should be able to stay at the bottom of the tube.

SiC powder is commonly used in industrial applications as an abrasive and cutting material, but it has also been used in research for bubble nucleation studies. It is a highly porous material that can provide a large surface area for bubbles to form, and its rough surface can provide sites for bubble nucleation.

When using SiC powder in your bubble light, it's important to use a fine grade of powder that will be small enough to fit in the tube, but large enough to provide the desired level of porosity. You may need to experiment with different sizes of powder to find the optimal size for your specific application.

As with any materials used in a scientific or engineering application, it's important to take appropriate safety precautions when handling SiC powder. Be sure to wear appropriate personal protective equipment, such as gloves and a respirator, and follow all recommended handling and disposal procedures.

assistant: Here are some good options for a material that is non-soluble in dichloromethane that will still enable bubbles to form while also being dense/heavy enough to remain at the bottom of the bubble light tube:
1. Table salt
2. Aluminum Oxide

There are also many commercially available options as well, these can be found under the names:
1. Boiling Beads
2. Boiling Stones 
3. Boiling Chips

These are referred to as "Boiling Aids".
If you are looking specifically for as porous a material as possible then avoid beads as they are smoother than granules and chips. 

Remember that dichloromethane is toxic. Avoid touching, breathing in or ingesting it. Use the appropriate precautions when handling it; gloves, eye protection and keeping your workspace well-ventilated is recommended.

Feel free to ask me any more questions you might have.

assistant: Based on your request, I suggest using silica gel beads as the material for your bubble light. Silica gel beads are heavy enough to stay at the bottom of the tube, insoluble in dichloromethane, and porous enough to create an ideal environment for bubbles to form. While working with chemicals like dichloromethane can be dangerous, it's essential to wear proper protective gear, such as gloves and goggles, and to work in a well-ventilated area. Have fun with your bubble light project!

assistant: There are several materials that could potentially meet your requirements of being heavy enough to stay at the bottom of the tube, insoluble in dichloromethane, and porous enough to promote bubble nucleation. Here are a few options:

1. Ceramic beads: Ceramic beads are often used in laboratory applications for their inertness and porous nature. They are also heavy enough to stay at the bottom of the tube. They come in a range of sizes and porosities, so you could choose a bead size and porosity that is suitable for your specific application.

2. Glass beads: Glass beads are another option that are often used in laboratory applications. They are also heavy enough to stay at the bottom of the tube and can come in different sizes and porosities. However, you should make sure to choose a glass that is resistant to dichloromethane.

3. Stainless steel mesh: Stainless steel mesh is another material that is both heavy and porous, and should be resistant to dichloromethane. It may be more difficult to find a mesh with a small enough pore size to promote bubble nucleation, but it could be worth considering.

Regardless of the material you choose, it is important to make sure that it is completely clean and free of any contaminants that could interfere with your experiment. Good luck with your bubble light!