One day last spring, near the middle of April, one of my students noticed a web of some kind high up in one of the trees on our playground. Soon, a group of children had gathered and they began to discuss what had caused the mysterious web.

I had a pretty good idea what it was, but I kept my thoughts to myself. It’s not all that common for children to come across such a unique and fascinating phenomenon. I wanted them to practice thinking of possible explanations. It’s hard, sometimes, to hold your tongue when you have the knowledge your students are seeking. But if you want them to learn not just the facts but also the processes that produce those facts, you have to allow for some struggle. Most students concluded that some kind of spider had made the web. One student thought that it could be part of the tree.

A few days later, I noticed that there were a few more webs in the same tree. One web was within my reach. I decided to break off its branch, so that we could observe it in the classroom.

Right away, the children saw that inside of the web was a group of caterpillars. At this point, I said, “Oh! I think these are called tent caterpillars.” We did a little bit of research and determined that there are two varieties of tent caterpillar that live here in DC. I printed pictures of those two varieties, which the children compared to our caterpillars. Everyone agreed that we had captured eastern tent caterpillars (Malacosoma americanum).

We kept the caterpillars for about two weeks. They spent most of their time hiding in the middle of their web, but they occasionally ventured out in groups, crawled around, expanded their web, and munched on leaves. We expected, based on our research, that they would consistently emerge at specific times of day. However, we were never able to identify a reliable pattern. They often came out shortly before lunch, but not every day.

As we continued to research eastern tent caterpillars, we read somewhere that they can live in various types of trees. I suggested that we could do an experiment to see if our caterpillars would eat different leaves. We started by adding a leafy branch from one new tree. The caterpillars didn’t take a single bite from it. One student observed that those leaves smelled “spicy,” and suggested that, “maybe they don’t like spicy leaves.” So we put in two other varieties of leaves, neither of which smelled spicy (according to our budding scientists). The caterpillars ignored those, too. We were skeptical, and rightfully so. I later learned that we had been misinformed in our research; it seems that eastern tent caterpillars only live on one family of trees.

The children also observed that there were little black balls in the caterpillars’ web. I was sure it was waste, but most of the children thought they were eggs. We took some out and put them in a small container, in order to test the egg hypothesis. Nothing happened, of course. A week later, we observed one of the caterpillars pooping. “I think it’s laying an egg,” one student proposed. I explained that it’s moths and butterflies that lay the eggs, not caterpillars. That convinced everyone that we were dealing with poop, not eggs.

Out on the playground, I combed over the caterpillars’ home tree and found something that looked more like tent caterpillar eggs: a bump on a branch that was likely caused by an insect of some kind. I broke it off and brought it back to the classroom. Alas, nothing ever came out of it; whatever was in there had probably already hatched, perhaps years ago.

The caterpillars’ waste had built up rapidly, and it had begun to stink, so we decided it was time to let them go. We released them one by one, carefully placing them back onto the tree where we had found them.

We saved four caterpillars, in the hopes that they would form cocoons, and two of them did. A couple of weeks later, we had two healthy-looking lappet moths. They weren’t very exciting as pets. They changed positions at night, but nobody ever saw them move. We tried putting the cage in a dark closet, hoping that it would awaken their nocturnal instincts. Still, they stayed put. When we took them outside to release them, I was able to get them to crawl onto a slice of orange. The first rested there for about a minute and then took flight. It flew directly to the bark of a small tree. A group of children followed it and one of them exclaimed, “It’s camouflaged!”

I don’t know if this particular set of activities is replicable. But, I wanted to share it because it demonstrates the potential richness of learning experiences that incorporate nature. Plants and animals can stimulate children’s wonder and curiosity like nothing else. Whatever outdoor space you educators and parents have access to, I encourage you to make the most of it.

My class is in the middle of an investigation of outer space right now. A pair of recent news stories has intensified their interest. This past weekend, a very bright meteor lit up the skies over D.C. One student was lucky enough to have seen it from his back yard. (Yes, I am jealous.) A couple of weeks before that, researchers from CalTech revealed evidence that there’s an undiscovered planet in our solar system, far beyond the orbits of the other eight planets. This new-to-us planet, dubbed “Planet Nine,” hasn’t been observed, but something big seems to affecting other bodies gravitationally.

There aren’t many clues as to what Planet Nine might be like. So I challenged my students to create their own renderings. Here’s what they came up with.

“I think it might have a tail. I think it might be green.”

“I think it has dots. And stripes.”

“This is a double planet…”

“I think it has fire balls…”

“It has circles…”

“I think it has my name…”

“I think it’s rainbow colored.”

“This is just a planet. It doesn’t have anything.”

Who knows; maybe one of them will be close. Of course, nature itself may very well reveal something even stranger.

This past summer, I introduced my class to a series of science activities using mealworms. I had expected it would capture my students’ interests for just a few weeks, but it developed into a deep investigation, which captivated us for most of the summer. I’d like to describe some of what unfolded.

First, a few tips. Mealworms are easy to care for. You can buy them at most pet stores—they’re meant as food for pet reptiles, and they’re usually stored in a refrigerator until they’re sold. They can eat a variety of foods (including polystyrene, apparently), but I recommend oat bran, because it serves well as both bedding and food. The only other thing they need is water, which they can pull from fresh vegetables. I used baby carrots, because they’re cheap, easy, and long lasting.

An Introduction

Before introducing my mealworms to the class, I let them grow fairly large—about an inch long. I hoped students wouldn’t have to wait long before seeing changes.

I didn’t tell the children what was going to happen. In fact, I didn’t even use the word ‘mealworm’ at first. Instead, we began by discussing larvae. I asked what they knew about caterpillars and butterflies (which was plenty). I pointed out that a caterpillar is one kind of larva—that there are many other types of insects that begin as larvae before changing.

Then, I pulled out the mealworms (“larvae,” I called them) and we started observing. I scooped them out of the terrarium and onto plates for closer inspection.

I asked children to speculate on what kinds of insects our larvae might turn into. Hypotheses included: butterflies, beetles, ants, bees, and flies. One student suggested that I get a lid for the terrarium, because he expected the larvae to change into flies.

Metamorphosis

Soon, we began to see changes. There was dead skin in the terrarium, evidence that larvae had been shedding their skin. We also noticed the appearance of small, half-curled little critters that moved very little, if at all. I suggested that some larva might have turned into pupae—the transitional stage between larva and adult insect. (A caterpillar’s chrysalis is a pupa, too, I pointed out.)

About a week later, we saw our first beetles. The beetles were white at first, making them difficult to spot in with the oat bran, but they slowly changed to brown or black.

Studying Individuals

At this point, the children were very excited. I wanted to find a way to extend our study. We hadn’t yet been able to study individual larvae, because they were unidentifiable and they moved around in the terrarium. So I decided to have each student care for a single larva, giving them a chance to observe their own mealworm’s development over time. I punched holes in the lids of small plastic containers. Children prepared their containers with oat bran and carrots, and then they each chose a larva from the terrarium. They named their new pet mealworms. (This was near the height of the Frozen craze; naturally, a full quarter of our mealworms were named Elsa.)

For the following two weeks, children checked on their mealworms daily. They made (mostly rough) drawings of the mealworms each day.

In that two-week period of time, most of the mealworms progressed from larva to pupa to beetle. When students asked to take their larvae, pupae, and beetles out of their containers, I tentatively consented, emphasizing the need for kindness and delicate care when handling live animals. There were some accidental drops, and children weren’t always gentle. (They discovered that they could get pupae to move by “tickling” them.) But the mealworms proved resilient. None of them escaped, all but one continued developing, and we had a lot of fun playing with them.

A New Generation

By this time, our original terrarium had produced twenty or thirty full-grown beetles. After each had emerged from its pupa, I had moved it into a second terrarium. Now, I presented children with a new possibility: perhaps the adult beetles (in the second terrarium) had laid eggs.

I scooped piles of oat bran from the second terrarium onto plates and the children set about looking for eggs. Although we never found anything that looked like an egg, our failure prompted a variety of thoughtful explanations from students: perhaps the beetles hadn’t yet laid eggs; perhaps the eggs were too small to see; perhaps the eggs were camouflaged. One student, drawing from prior lessons on mammals, suggested that beetles might not lay eggs. “Maybe they’re mammals,” she posited.

However, after more careful observation, we did find a fresh set of tiny mealworms! They weren’t easy to spot, but after patiently watching piles of oat bran, we often noticed very slight movements. With careful digging, we were able to locate and isolate these new larvae. My students were so enthralled with searching for these tiny critters that we continued hunting for nearly two weeks.

If you’re looking for a science activity to try with young children, I recommend getting mealworms. They’re cheap, easy, and fun. And with the right guidance, they can present great opportunities to practice thoughtful, creative, early scientific thinking.