For those that travel on a path slightly more gooey. Viscosity! It's the stickiness of life that keeps everything from lava to jelly in check. With the viscosity tube tumbler, you can look at everything from air bubble races to density columns to sedimentation in real time. Grab your glitter, your honey, oil, alcohol, your dirt, your sand, and let's go on a viscous and dense ride. This is great for any home, museum, or classroom, too!

What: Viscosity Tube Tumbler!
Concepts: viscosity, fluid dynamics, density, sedimentation, physics
Time: ~ 2 hours to make
Cost: ~ $20 including tubes
Materials:
- Clear Tubes (we used 5 x 1" tubes that were 23" long)
- Tube Caps (we needed 10)
- Duct Tape
- Rubber bands (we needed 10 thick ones)
- Wood (we used about 1/4 sheet of 3/4" ply)
- 2 Lazy Susans (we used 4" square ones)
- Wood Screws
- Things to fill tubes with! (oil, honey, water, food coloring, glitter, sand, dirt, alcohol)
Tools:
- Saws (a range for cutting wood)
- Drill
- Sandpaper
- Funnel (optional)
- Syringe or pipette (optional)

Tubular! Let's do it!

Step 1: Leakiness Check!

All righty! You got all your materials, and now to check to see if things can get through. With a correctly sized rubber end cap (ours are 1") you should be good to go. But it's good to make sure so you don't end up with liquid disasters later. :)

While we're getting started, it's a great thing to learn about the difference between viscosity and density. There's a good write-up here!

Step 2: The Tube Holder

This is like a giant test tube holder. We measured our tubes at about 1" wide, so we decided to cut holes with a 1 1/8" forstner drill bit to make 5 holes evenly spaced apart. Our board happened to be 13" x 4", but choose whatever you like.

Step 3: Two End Circles

These are going to be what attach to your tube holder. Make sure they're big enough to hold your Lazy Susans on, but the diameter is up to you. We made ours about 9" in diameter. Cut them out and sand them on down. Huzzah!

Step 4: Screw Together

Time to make a wooden barbell. Measure out where your tube holder should go on your circles so that it is centered. Outline the tube holder in place on the circles, and make a pilot drill hole. This will make it easy to line up when you drill them together from the other side.

Do the same on both sides for four screws total!

Step 5: Side Supports

These will hold your spinning contraption in the air. Because our tubes are 23" long (we cut them after this photo), we decided to make the support a little over half that to give some clearance for the tubes on the ground. We chose to make ours 16" tall, which was cutting it close. They are 6" wide, and we added in some curve just for aesthetic purposes.

End by screwing in one of the Lazy Susans to each one, making sure they're square and at the same height on both supports. We used 4" square ones.

Step 6: The Other Side of the Lazy Susan

This is the trickiest step! Drill a pilot hole in your side support through the top plate of the Lazy Susan. Then drill that hole out with a much bigger drill bit.

Swap over to your end circle, and draw where the Lazy Susan should go, making sure it's centered. Then place the two together, and use big hole you made to screw the plate in to the end circle side. After you get the first screw in, you swing around your side support to get to the others.

This is tricky, but once you get the idea, it'll make more sense. There are bunches of videos on installing Lazy Susans, that I watched because my first time installing one, I also had no idea what to do. A good one can be found here.

And if you got it, YAY! It spins!

Installing a lazy susan is the opposite of lazy. I now realize that all the energy people save from swinging their food around in a circle is spent by the people installing the hardware. :)

Step 7: The Wood Base

Choose a wood base from a board a little larger than your contraption. I rounded the corners on ours with a band saw (optional), then marked where the supports should go, making sure it was all squared up. Make a pilot hole on the side you marked, then screw in the base from the other side.

You can counter-sink them, too to avoid unevenness. Or in the case of this soft wood, just drill the heads a bit deeper into the wood. :)

Step 8: Tube Time!

We're now going to make something to hold the tubes in place. We wanted something that would stick, but we could also take off to clean or change out the contents of the tubes. After much experimentation, duct tape was the answer (isn't it always?)

Find the center of your tube, and wrap duct tape around it. Check to see how much you need to make it snug within the hole. After you find the right number of wraps, wedge the tube in and add rubber bands to both sides as safety stops to prevent slippage. Repeat for all five tubes.

Step 9: End Caps

Add end caps to one side of each tube. Adding a little duct tape is good to really make sure you got a seal, and that students won't pull them off. They also make a great place for labels of what's in each tube.

Step 10: Adding Liquids

There's so many (infinite) to choose from! The basic method of adding liquids is to use a funnel, and pour in on in until the tube is mostly full. I find a good a good amount is just enough so that you can't see the air bubble when the end cap is on. If you put in to much, you can remove a little with a pipette or syringe. When you're all done, cap it and duct tape it up.

Translucent liquids are your friends here, and you can color them with food dye. Some great ones so start with include: honey, alcohol, water, and oil. A great one to do is even a combo of two of them.

Step 11: Adding Other Things

There are so many things to add, and your tubes don't just have to be about viscosity. Some of our favorites include adding glitter, adding different sediments to water, magnetic sand (with iron), and you can experiment with much much more!

Pictured here too is a failed experiment with molasses. It's just too dark to see the air bubbles inside, oops! If you mess one up, just open it up, wash it out, and try something new!

Step 12: Take Your Tubes for a Spin

Give them a spin and see the air bubbles race, the glitter scatter, the sediment separate, and the ferrous sand cling to the whichever walls have nearby magnetics. There is so much to do with your tube tumbler, and we can't wait to hear what you come up with.

As always, keep exploring, and happy happy tumbling.