I use simple physical models extensively in my research. Building physical models is a fun, creative process that forces the builder to think critically about how biological systems work mechanically.
In my work, a huge portion of the "observation" portion of the scientific method occurs during physical model building.
Below are some tips and resources for building models of soft biological cells and tissues.
Tube Method #1:
Here's one method for making flexible tubes out of silicone rubber. This is from Smooth-On's 'How-to' site, which has lots of useful tutorials.
I used this method to make the muscle fiber models in Sleboda and Roberts 2020. Instead of the "powermesh" fabric shown at 1:50, I wrapped the tubes in layers of sewing thread so that I could vary the pitch of the reinforcing fibers.
YouTube: "Medical Simulation: Making Suturable Vessels" by Smooth-On
Tube method #2:
This is a really interesting looking extrusion-based method. I haven't tried this one personally, but it looks like it would produce tubes with more uniform thickness than method #1.
YouTube: "Home made silicone fuel line?" by EngineerNick
This is a very useful knot for making air and water-tight connections. A couple of these make a light-weight and unobtrusive replacement to a zip-tie or hose clamp.
YouTube: "Super Useful Knot - How To Tie A Constrictor Knot" by WhyKnot