Author Archives: Joe

After a recent snowfall, my class ran some experiments with snow, salt, and sand. Science experiments have been prevalent in my classroom for many years. But until recently, most of them we carried out as large-group, teacher-led activities. I redesigned my science center this year, hoping to give children more opportunities to set up their own experiments.

Many students came with some prior knowledge about what salt does to snow and ice. We live in Chicago after all; snowplows are a familiar sight. I challenged some assumptions, however. I asked, “Are you sure? How do you know?” As a group we briefly talked about how experiments can help us see if something is true, and also help us learn new truths.

Getting Things Ready

In preparation, I filled containers with snow and stored them in a freezer. If it’s in a fairly large container, the snow won’t melt for hours after it’s removed from the cold. Then I poured sand and salt into separate condiment dispensers. And I made small signs with the words ‘salt,’ ‘sand,’ and ‘just snow.’

My instructions were somewhat vague: fill two containers with snow, do something different to the two containers, and then watch what happens. I wanted children to make their own decisions about what to compare. I expected that we’d end up with a wide variety of arrangements, and we did.

Minutiae and Minor Setbacks

Things did not go quite as I had planned. (They rarely do.) At first, I had children filling small plastic test tubes with snow. I reasoned that it would be easiest to observe our results in test tubes, on a rack. But it was pretty difficult for the children to get snow into the small tubes. They became frustrated.

On day two, I adjusted by setting out little round containers instead. It was harder to tell how much snow had melted, but students were able to set up their experiments much more independently.

Another hiccup: children had trouble distinguishing between words on the tiny signs. I knew this would be a challenge, but I also thought it would be a nice way to incorporate functional reading skills into a fun activity. Alas, the words ‘snow,’ ‘salt,’ and ‘sand’ were too similar for most students to distinguish without significant support, which distracted them from main goals of the activity. I should have included tiny pictures of saltshakers, sandy beaches, and snowflakes.

Also, many students disregarded the word ‘just’ and placed ‘just snow’ signs in each of their containers. As a result, most containers were labeled as ‘just snow,’ even if they contained salt or sand, and I ran out of ‘just snow’ labels.

Perhaps the toughest challenge in designing activities for my new science center has been anticipating which minutiae have to be in place for an activity to succeed. It’s hard to think like a young child—it’s a big part of my job—and I’ve learned to expect that I’ll overlook some notable detail each time I roll out a new activity.

Results and Conclusions

Although things didn’t go as smoothly as I had hoped, this was a successful activity. Students were able to set up experiments independently, they were highly engaged, and they had fun.

We ended up with more “salt and snow” conditions than any other type, probably because it’s more fun to add more ingredients. The experimental conditions were not very well controlled, of course—nothing was precise. Still, most students walked away convinced that salt melts snow, and uncertain about the effects of sand. When students disagreed about their results, I used it as an opportunity to talk about the commonality of disagreement among scientists.

Most importantly, we saw how a simple comparative experiment can help us learn about the world around us. The scientific method, in its simplest form, is accessible to young children. All it takes is a little bit of scaffolding.

I taught my students about outer space last month. We learned many facts about planets, stars, and more. But while science education for young children often emphasizes the factual knowledge, I want my students to do more than regurgitate. I want to foster an early understanding of scientific methods, because it’s not the products but the processes that set science apart.

When we talk about science, I often remind my students that scientists try to learn new things. That means they come up ideas—hypotheses—that might be wrong. Sometimes, scientists must change what they think.

Pluto offers a nice example. Every year, a few students enthusiastically declare that Pluto is no longer a planet. But if I ask follow up questions, they usually reveal that they think Pluto changed in some way—that it was a planet until something happened to it. Of course, the only thing that changed is in our heads. Scientists used their instruments to learn more, and that changed how they think about Pluto.

To give my students practice making their own hypotheses and changing what they think, I set up an activity with meteorites. I put out sixteen rocks and told them that some had come from outer space and crashed into the earth. I challenged them to come up ideas about which ones were from outer space. They weighed the rocks with our scale, and looked at them with various magnifying glasses. I asked many open-ended questions to flush out students’ reasoning.

A handful of hypotheses emerged. Some students thought that meteorite must have “holes” (craters) like the Moon and Mercury. Some thought that the meteorites would have to be a certain color, perhaps black. Some looked for scratches caused by crashing into the earth. And some students were more vague, saying things like, “I just think it looks like a space rock.”

On the third day, I asked students to start recording their ideas on a chart. Each rock had been assigned a letter. Students circled ‘yes’ or ‘no’ for whether they thought each rock was a meteorite. On subsequent days, I reminded them that they might want to change what they think, and many did.

When I was ready to wrap things up, we sat down to have a summary discussion. We began by making a graph that represented how many students thought each rock was from outer space. There was some consensus, but much disagreement.

Then I pulled out my computer and together with the class did some (staged) research on what meteorite scientists have learned, because they have looked at many more rocks than we have, and they have done experiments on them. We learned two pieces of useful information. First, meteorites are heavier than most rocks of the same size. Our rocks varied in size and some of our small rocks weighed little enough that they wouldn’t register on our scale, so to avoid confusion I moved on. Second, because meteorites have iron in them, they will stick to strong magnets. We pulled out some strong magnets and tested each rock. We found two that were magnetic. (They are, in fact, meteorites; I purchased them here.)

Now, I don’t really care if my students learned that meteorites are magnetic. That wasn’t my goal, so I didn’t stress that point. Instead, I emphasized the way new information had changed what we think. I asked, “What did you think before? What do you think now? Have you changed your mind?” One or two students maintained their previous positions. If they were scientists, I told them, they would need to learn more about meteorites. Then maybe they could make the rest of us change what we think again.

We recently had a visitor in our classroom. Emily Conover is a physicist and science writer who earned her Ph.D. in high energy physics. She offered to teach my students a little bit about particle physics and to set up an exciting experiment for our new science center.

I talk to my students about scientists frequently. Whenever there’s an opportunity, I ask them to think like a scientist. Sometimes I wonder if they ever ask themselves, “Why does Joe talk about scientists so much? Can’t he just answer our yes-or-no questions?”

I also wonder what our youngsters picture when I start talking about a scientist. Is it something vague? Is it a man with glasses, pouring liquids into beakers? Having a real life scientist in our classroom gave us a better idea of what a scientist can be like. Emily shared some photographs of some of the instruments she helped build, and of the laboratory in Chooz, France where her experiment is carried out.

Particles and Electrons

Emily also taught us about particles. We learned that everything is made up of very tiny things, much too small to see. Bigger things you can break apart. We can break a cookie, for example, into smaller and smaller pieces. But when it’s as small as a particle, you can’t break it up anymore. That lesson was pretty abstract for our youngsters, but it was a nice introduction.

Next, she taught us about one particle called the electron, which sounds a lot like the words ‘electric’ and ‘electricity’ because when we use electricity, we send tiny electrons through wires.

Knowing that electrons can go through wires, we asked the scientific question: what else can electrons travel through? To test it, Emily and I set up a small light bulb, attached to a nine-volt battery, with a break in the wire. We explained that the light bulb would only turn on if the electrons from the battery could go all the way around to the light bulb.

Note: we took a minute at this point to talk about safety. We certainly don’t want children going home and playing with wires. We explained that electricity is very dangerous; our experiment was safe only because we used very small batteries.

We then set the children loose in our science center and let them experiment, sending electrons into each object and checking to see if they made it all the way to the light bulb. I set out a variety of objects—different shapes, sizes, and materials—and I invited the children to pick other classroom objects or toys to try.

In a matter of minutes, a group of students had discovered that metal seemed to be key. Word spread quickly among the rest of the class, but everyone was eager to test it out nonetheless.

A few metal objects did not work: a non-stick pan and some metal objects with paint on them. They offered opportunities to reevaluate our assumptions, which is the type of thinking I aim to facilitate. Scientists often must change what they think, as I regularly remind my students.

One student was particularly interested in seeing whether electrons could travel through a chain of objects.

We purchased most of the materials that we needed at RadioShack. It took some time to put things together, but it was fun. I’ll hang on to them and use them again in coming years.

I want to thank Emily for thinking of an excellent idea, for carrying it out beautifully, and for taking the time to visit us. My students were lucky to have you.

One of my big goals for this school has been to expand science education in my classroom. I’ve always given my students a pretty healthy dose of science, but much of it came in the form large group activities and discussions. Every year, we learn about many scientific topics, and we run many experiments as a group. But we lacked a dedicated space where children could independently engage in scientific activities on a regular basis. So I rearranged my classroom and made room for a new science center.

A typical preschool science area contains a few basic tools: magnifying glasses, a balance,  rulers, a tape measure, magnets. Children enjoy using these tools, but I’ve found that their novelty wears off rather quickly. Unless they’re given new purposes, they’re soon used used as props in imaginative play scenarios more often than as scientific tools. I don’t have a problem with that–in fact, I left some of our old magnifying glasses with the kitchen toys, where I would often found them–but I wanted to have a set of tools set aside exclusively for scientific activities. These are the items I purchased:

• Magnifying Glasses. Probably high up on any list of scientific tools. I got a few different kinds of magnifiers. These standard magnifying glasses have both 3X and 6X magnifiers on them. However, it takes a little bit of skill to focus them. Many students prefer to use these little “bug boxes” or these “pre-focused” magnifiers. I usually set them all out.
• Rulers and Tape Measures. Which type probably doesn’t matter much. I got these translucent rulers and I already had some small tape measures that work well.
• Scale. Instead of a balance, I decided to get a scale. Young children tend to want to fill balance buckets with as many objects as possible, which becomes a bit of a distraction from the concepts they’re designed to teach. A scale has the advantage of injecting numbers into our science activities. My students can still compare the weight of two objects; it just takes an extra step. (I have a number chart on the wall in the science center, for students to reference.) It was tough finding a good scale. I settled on this digital scale, which has a grams setting. Most digital scales that use ounces or other units show a decimal point, which confuses young students. A digital scale that’s set on grams usually doesn’t include decimals.
• Small Containers. I gathered a variety of small containers, which we’ll be using to run experiments. Most were old plastic containers I had in storage, but I also purchased these plastic test tubes.
• Tweezers. We might want to handle some very small objects at some point. I wasn’t sure if the kids would be interested in these tweezers, but they love them. They want to use them for everything, so I remove them when we’re handling fragile objects.
• Stop Watch. I’m still unsure how exactly we’re going to use this, but I want to give my students some experience measuring time. I purchased this timer because, as with our scale, it doesn’t show decimal points.

Preparing Activities

Acquiring new tools was the easy part. The challenge has been preparing a steady series of interesting activities for my students to engage in. There are a lot of early-science resources available, but they often have limitations. Most of the activities I’ve found fit in one of two categories: (1) run an experiment that is largely teacher-directed, or (2) offer various items (often from nature) for students to examine. Teacher-led experiments we do carry out regularly, but they don’t fit well in a learning center that’s driven by student choice. Exploratory examinations are going to be a regular fixture in our new science center, but they lose their appeal if offered too regularly, and I don’t want to stop there.

I want my students to manipulate things and make simple comparisons. I want them to interact with objects, come up with ideas, and then test their ideas. Young children can understand the scientific method at a basic level; they’ve shown me consistently. They’ll learn it even better if I give them abundant opportunities to practice. It’s going to take some creativity and some hard work, but I’m looking forward to the challenge. Stay tuned for updates on my recent efforts.