In the past month I have been occasionally visiting local third-grade classes with some colleagues to deliver a lesson on adaptive variation. It isn’t as dry as that makes it sound—there are puzzles and tiny spoons and squishy fishing lures. We are fun scientists. Science is fun! Science is fun but if you don’t put the fishing lures back in the bins and pay attention, we won’t get to start, okay, I know they’re gross, please don’t throw them, thank you, as I was saying, science is fun!

It has been interesting to see how much difference there is between classes. One class squirmed and giggled whenever we suggested that animals might need to find, as we put it, “boyfriends and girlfriends.” Another class was completely unfazed. “Yes,” one student in that class clarified, “they need to find mates.” Every class so far has known about camouflage and what hummingbirds eat.

In one class we visited, we were repeatedly asked whether we had brought any brains for the students to touch. Some were disappointed that we had not brought brains to touch; others, clearly worried by the prospect, looked relieved. Another class was disappointed that we had not brought any live animals with us. “Well, then did you bring any plants?” they asked, giving us one more chance to be cool. “I could go outside and get some,” I joked, to absolutely stony faces.

This is the third demographic I have taught, adding to my experience teaching college students and prison inmates. After the inmates, who tended to be too shy to volunteer much, and the undergraduates, who seem to want to participate only exactly the minimum acceptable amount, the third graders are shockingly enthusiastic. They all want to volunteer. We have to cut them off when it seems that they could tell us about Tasmanian Devils forever. We have to move on to new topics while there are still eager hands in the air, wanting to offer another example of a species or another definition of “predator” or simply to grin at all the attention and whisper “I forgot what I was going to say.”

It’s hard not to get swept away in this gratifying enthusiasm, especially since the students often have such good things to say. “A predator is… kind of like an enemy,” one student offered, then amended thoughtfully, “but not.” Another student ventured that a biologist might be “someone who studies biography?”

One boy, upon learning that one of my colleagues is from Norway, exclaimed, “That explains a lot! That must be why you have so much of the f-word.” My colleague was rather taken aback at this; she is not prone to profanity, and was not aware of any exceptional tendency toward vulgarity in her home country. Eventually it became clear that by “the f-word,” the boy had meant “freckles.”

Of course, not everyone is into it. When I asked one boy, “What do you think is different about these birds?” he declared, “I hate birds!”

At the end of the lesson we try to leave some time for questions. One class had evidently been talking about feelings lately. “How does it feel to be a scientist?” asked one student, while another sighed, “I was going to ask that!” Then the follow-up: “How does it feel to study bugs?” My colleague who studies bugs tried to explain why she likes bugs, but the students did not look convinced.

Sometimes we are quite disappointing to our interrogators. “Do you build robots?” No. “Do any of you make explosions?” No. “Do any of you study penguins?” No. “Do any of you study any kind of dog?” No. “Do any of you study animals that live in the sea?” “Yes!” We exclaimed, relieved to finally be living up to expectations. One of my colleagues had studied octopus. I offered that I had briefly studied sea urchins, which was less well-received than the octopus.

Sea urchins are cool! They wear stuff like seaweed and snail shells!

At the beginning of each lesson, we briefly introduce ourselves. We, of course, try to make ourselves sound as cool as possible. “I have had a baby bird hatch in my hand,” I say. “And I am in the 21st grade.”