Works as expected: using hot coffee, a lighter, etc. to get the wheel spinning. Can observe the inside, shiny metal finish on visible surfaces. I'm giving this as a gift, and I anticipate a happy receiver.
Interesting piece of engineering in small format!
My son bought me this for my birthday. We are both engineers by training and love interesting but useless things - this is one of the best I own in that category. The quality is first rate, it is fun to watch and I place it on top of my tea cup every morning as part of my early morning "ritual". Any scientific type will love this.
Ok so I bought this thing because I love physics items and this seemed like I very nice functional item to have displayed in my house.