100%

In K class, I got to complete the ice-water-steam-vapor demonstration that was cut off due to lack of time the week before. The demo gets more exciting when you show that "other things also have solid and liquid states". To do this, you melt some butter (smells nice), then you get out your pocket butane torch and melt some solder, which is an eye-opener for somebody who's never seen metal turn runny, and drip and splash.
We also talked about lava and spiders.
Lava and spiders?
Sure, great combination.
Actually it was mostly about spiders, and the lava is more like a universal constant - - everybody loves lava, you can talk about it at any time of day or night, and kind of weave it into unrelated conversations. Would you like Corn Flakes or Cheerios? I'd like Corn Flakes, with molten lava please.
The spider discussion - - launched by one question in the question box - - achieved a marvellous 100% participation rate. Sometimes I think that you are wondering, does my child participate in these science fandangoes? In this case, the answer is yes because absolutely everybody had at least one question or a comment. 100%.
A remarkable question during the Q&A concerned whether spiders are reptiles. That might sound odd, but it gets interesting when you hear the full question as asked:

Since spiders lay eggs, does that mean they are reptiles?

Now we see that the questioner is thinking really hard, and very rationally. I want to construct large sweeping rules of categorization! I have data, but I need more data! How significant is egg-laying as a classifier?

For Silver Surfers we had an action dramatization of the role of blood in the body. As a blood cell, I ran around the circle of body cells (the role of body cell was excellently played by a cast of Silver Surfers), and brought needed cell nutrition (represented by peanuts) to the cells, and took away metabolic waste (represented by peanut shells). I also handed out a few choice oxygen molecules (the ubiquitous styrofoam balls) to those cells that needed them.
I wonder if I could make like a leitmotif of always including at least one styro ball in every class.
Science as conceptual/performance art.
Maybe Yoko would be interested.
Did the action drama work? Do all the students suddenly understand blood circulation? Let me know if any clues pop out. Sometimes we find out many months later, when a remark pops out of the blue "sure, Mom, I know what blood does. It carries food just like our science specialist handing out peanuts!"

Insect blood (or, hemolymph anyway) is quite different. For one, it doesn't actually flow in tubes. It just slops around. So you'll never see an insect as big as a Golden Retriever because the system for getting nutrition to cells is just not good enough. As we say in computer science, it's not scalable. For another thing, insect hemolymph does not carry oxygen. At all. It's just not in the job description.