A: A great science investigation uses questions, activities, experiences, and examples to help students develop a concept, deepen their understanding, and apply the concept to new situations. A great lesson starts with some exploration of some phenomenon—perhaps a discrepant event, a toy that does unexpected or interesting things, or an attention-grabbing demonstration. This exploration can occur at the student’s own pace and with little guidance. Students often become highly motivated when they are permitted to do hands-on explorations before the concept is introduced.
Having piqued their curiosity, students are now ready to start learning and understanding what they observed. Discussing with one another in groups, some students might start to figure things out or at least have some ideas or hypotheses, which are tentative explanations. Students can learn to use and understand various science practices, such as observing, collecting data, categorizing, ordering, comparing, inferring, relating, communicating, and applying. They might then carry out another, more structured exploration allowing them to reexamine the same objects and phenomena more systematically.
We can then guide them to a more complete understanding. We’ll use scientific vocabulary to introduce the concept related to students’ observations. Note: Asking students to memorize definitions of terms is not science and does not result in long-term learning. What works better? Use a term in context, reminding students of the meaning the first few times you use the term. (After all, hearing words used in context is how we all learned to speak, right?)
Together, the teacher and students organize the observations and experiences, and the resulting patterns often match the targeted concept of the lesson. During discussion, the teacher and students compare how the newly introduced concept relates to students’ preconceptions. We can further explain the concept by using stories, pictures, video, and other materials.
After students receive the explanation, many teachers will conclude the lesson and move on to the next topic. But that shouldn’t be the end of the lesson. If we really want to create long-term learning—and be able to assess that learning—then we should give students opportunities, especially through the use of hands-on activities, to apply the concepts to other situations. These additional activities will often serve an additional purpose as being the initial activity in the exploration phase of a new, closely related concept that will be developed in the next lesson. In our quest to get students to appreciate the fascinating adventure that science can be, it is gratifying to know that the hands-on activities in the exploration and application phases can serve to motivate students as they encounter puzzles that arouse their curiosity.
The research tells us that, to spark high-level thinking, teachers should ask questions that require some mental processing on the part of the student, rather than asking questions that only require a student to recall something from memory. Here are some questioning strategies that elicit higher-level thinking from students:
Students can learn a lot by trying to solve a practical problem. One way that this investigation is made more student-friendly is by the use of animal crackers. The idea is that an animal (cracker) needs to get to the other side of a river. Students can give their animal a name; let’s say, “Robbie the Rhino” (Figure 1). Robbie needs a raft in order to get over to the other side. Robbie needs to stay dry, otherwise, being an animal cracker, Robbie would get soaked and break up into pieces. The students’ job is, using the available materials, to make a raft that will float across a basin of water (Figure 2) with Robbie staying dry in the raft. Possible materials include craft sticks, aluminum foil, glue, tape, rubber bands, newspaper, toothpicks, plastic bags, cotton balls, etc. This activity involves both science and engineering.
Working in groups, students should discuss what materials would work best. If they need guidance, ask questions like, “What characteristics should the raft materials have?” One possible answer is that the materials must be waterproof. If a student mentions that, you can ask, “What does waterproof mean? How will you know if the raft is waterproof?” The idea is to get students to think about some tests they could perform with the materials prior to constructing a raft out of them.
Students might also realize that they need materials that will float. Here it would be useful for the students to understand buoyancy. I discussed buoyancy a bit in a previous Science 101 column (see Online Resources). Another useful concept is density. The key idea is that if the density of an object is greater than the density of water, then it will sink in water. If the density of an object is less than that of water, the object will float. Low-density objects don’t have much mass for their size. An example would be an air-filled balloon, which can easily be seen to float. A high-density object has a lot of mass and is heavy for its size, such as a coin or a rock, which will be seen to sink in water (Figure 3). Even without knowing any of that, students can experiment and discover that it’s the low-density materials (i.e., the ones that feel rather light for their size, that will float).
The balloon has low density, so it floats on water. The rock has high density, so it sinks.
Armed with this information, students can decide which materials are waterproof and which ones will float. Then they can be confident that a raft made out of these materials will get Robbie to the other side of the river. Before actually constructing their raft, students should draw a picture in their notebook of what the raft will look like, and they should label the different parts.
Science is an excellent vehicle for motivating students to practice their language arts skills. Besides practicing oral communication with the other members of their group, students should be writing in a notebook all of their ideas and all of the experiments they did as part of this activity. Their first attempt at making a raft might not have been successful, so they might decide to make some modifications and try again. For each attempt, they should write in their notebooks: What materials will they try making their raft out of? What was changed since the previous attempt, and why?
For more oral communication and collaboration: After all groups have finished constructing their raft, students can discuss with other groups what their group did and why. What features do the designs from different groups have in common? How do they differ? Have students reflect on how they made use of evidence in revising their raft design. This is a key way in which science differs from other ways of thinking: Science is based on evidence.
Still have extra time? (Ha-ha) Have a contest to see whose raft can hold the greatest number of animal crackers and keep them dry.
Is the lesson over? I hope not. Get students’ ideas for how what they’ve learned could be used in the real world. For instance, how would the density of a submarine need to be changed if the occupants want to bring the submarine up to the surface?
Many real science and engineering investigations do not have definite ends or conclusions. For example, students could go on making improvements to their rafts again and again. This is what real science is like—an ongoing adventure!
Did you notice that in this activity there wasn’t a definite sequence of steps for the students to follow? Students were able to do different parts of their investigation in different ways, in a different order. They could repeat and revise as needed—just like we do in the “real world.” Real-world science doesn’t involve a series of steps, and there’s not always a single correct answer. (Many different types of rafts would be acceptable.) Real science is exploration and discovery—and lots of fun!
Finally, just as some (perhaps, the best) scientific investigations are open-ended and could keep being extended or expanding, so too is learning an ongoing endeavor. Isaac Asimov said, “Education isn’t something you can finish.” That’s why I always say…
Never stop learning. ●
Science 101 article on buoyancy (August 2019): https://www.nsta.org/science-and-children/science-and-children-august-2019/science-101-how-can-you-weigh-less-without
Matt Bobrowsky is the lead author of the NSTA Press book series, Phenomenon-Based Learning: Using Physical Science Gadgets & Gizmos. You can let him know if there’s a science concept that you would like to hear more about. Contact him at DrMatt@msb-science.com
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