- Students will recognize that curiosity, perseverance and the ability to solve problems are qualities they possess.
- Students will understand that the work of scientists involves posing a hypothesis and working toward supporting or invalidating it.
- Enduring Understandings:
- Curiosity, perseverance and the ability to solve problems are some of the qualities that each of us possess.
- Scientists use many approaches in their work, such as posing a hypothesis and finding evidence that supports or invalidates it.
- What evidence do we have that all of us can claim “scientist” as part of our identities?
- How do scientists approach their work?
- A video clip of a TED Talk given by Alison Gopnik (12:22-14:29) and a means for projecting it.
- Two identical clean, clear glass jars with screw-on lids (for example, baby food jars or mason jars)
- Two chunks of wax of equal size (for example, birthday candles or tea lights)
- Duct tape or packing tape
- Tap water
- Rubbing alcohol with a 70 percent solution or higher (Caution: Use care with rubbing alcohol. Keep away from flame. Avoid contact with eyes and skin. Avoid breathing fumes. Not to be taken internally.)
curiosity [ kyoo r-ee-os-i-tee ] (noun) the desire to learn about something
evidence [ ev-i-duh ns ] (noun) something which shows that something else exists or is true
hypothesis [ hahy-poth-uh-sis ] (noun) a possible explanation; an idea used to guide an investigation
identity [ ahy-den-ti-tee ] (noun) the attributes that make a person an individual, such as gender, race or ethnicity, religion, role (for example, student or teacher), sexual orientation, nationality, ability
perseverance [ pur-suh-veer-uh ns ] (noun) ability to stick with something
STEM [ stem ] (noun) acronym that stands for science, technology, engineering and mathematics
Before Lesson Prep
Before teaching the lesson, prepare the floating wax discrepant event demonstration using the directions below. You may prefer to design your own demonstration if you’re immersed in a science unit with a different focus.
- Pour the rubbing alcohol into one of the jars. (It should be deep enough that the wax in step three will be completely submerged.)
- Pour water into the second jar, filling it to the same height as the first jar.
- Drop a chunk of wax into each jar.
- Screw the lids on the jars and seal each with tape.
Teaching with discrepant events
Discrepant events are often used in inquiry-based science classrooms to introduce a new topic or to assess students’ conceptions and misconceptions midway through a unit. As in the floating wax experiment above, there’s a discrepancy or contradiction between what the observer expects (the two pieces of wax should behave in the same way) and what actually happens (one piece of wax floats and the other piece doesn’t float). A discrepant event provides an opportunity for students to practice scientific thinking, ask questions about what’s going on and suggest ways these questions might be answered.
Whether or not you follow through on students’ investigative suggestions depends on the class time available, and this investigation can be deferred to another day. Note that if students suggest that the liquid in one jar might be different from the liquid in the other jar, you’ll want to demonstrate safe ways to investigate. No tasting, touching or even directly smelling unknown substances! Opening the jars should be enough to prove that the liquids are not the same.
Explanation for the floating wax experiment
Here’s the explanation for what students are seeing: Wax is less dense than water, which allows it to float, and wax is denser than rubbing alcohol, which makes it sink. There’s no need to share this information with students! Density is a complex topic often not addressed until middle school or later—and students don’t need to know the term density or the complete explanation for the experiment. If they’re interested, they may want to explore what substances float in different liquids. (Water, oil and corn syrup have different densities.) See this article for more on density.
Let students know that they’re about to begin a series of lessons on STEM. Explain that STEM stands for science, technology, engineering and mathematics. Note that when you talk about people who work in these fields, you’ll use the word scientists for short. Share the Essential Questions for the day, defining evidence and identities if needed.
Explain to students that they’ll learn about what scientists do at work. Students may be surprised to know they have been doing similar work to scientists since they were little kids!
Explain that people who study the behavior of children think that kids may actually be better than adults at scientific thinking. Ask students to consider how this might be possible. Explain that they’re about to watch a video of a 4-year-old boy to find out.
- Prepare students for watching a two-minute clip of a TED Talk given by Alison Gopnik. Explain that this video is part of a talk for adults who are watching together in a big auditorium. They will hear the adults laughing as they watch a video of a boy—and students will probably be able to figure out why. There is a researcher in the room with the boy, and she’s asking him to solve a problem, “Why is one block lighting up and the other block is not?” No one else is in the room. The boy comes up with one hypothesis (an idea about what’s happening) and then another and another.
- Show students the video from 12:22-14:29.
- After viewing, ask the following questions:
- What problem was the boy trying to solve?
- What did you notice about his approach to solving the problem?
- What words would you use to describe him?
- Explain that the recording they watched came from the laboratory of a scientist named Christine Legare. She repeated her experiment with many children. All the kids tried different things and explained what they were doing. Ask students if they think the boy found the only correct answer or if there were more ideas still to be tried. What makes them think so? Explain that this boy—and the other kids in the experiment—showed two very important characteristics of good scientists: They asked questions and they kept trying.
- Tell students that you’ve prepared a scientific demonstration to share with them. Their mission is to review the evidence you’ll present and come up with some hypotheses. Casually mention that the subject is pretty advanced, usually not studied until late in middle school. Remind students that as they make and listen to suggestions, you expect to see the behavior of scientists, particularly respect for others’ ideas.
- Display the jars you prepared before class. Say something like, “Before class, I dropped an object into each of these jars of liquid. Check them out. What do you observe? What do you think might be going on?”
- Call on students for suggestions, making sure to solicit comments from a variety of students. List suggestions on the board, encouraging students to come up with as many ideas as possible. These might include ideas like maybe the objects are not made from the same material or maybe one object is heavier than the other. When all suggestions have been heard, ask:
- Which of these ideas would you like to test first?
- How would you go about it?
- Where could you go for more information about this subject?
- What keywords would you use for a computer search?
See tips for following through on students’ investigative suggestions in the “Before Lesson Prep” section.
Congratulate the students on their curiosity and perseverance. (Define curiosity and perseverance if needed.)
Write the following questions on the board and have students pair up to discuss:
- Were everybody’s ideas treated with equal respect? If not, whose ideas were considered most valuable? Why? What effect did that have on other students?
- Do you agree with the idea that “scientist” could be part of your identity? Why or why not?
Reconvene the class and have them share their ideas with the larger group.
- What, if anything, about trying to solve this puzzle was fun? What, if anything, was frustrating?
- Do you agree with the idea that everyone has “scientist” as part of their identity? Why or why not?
- Did it seem like everybody’s ideas were treated with the same respect? What happens if/when some people are left out of the discussion? What can you do as a class to make sure this doesn’t happen?
Reconvene the class and have them share their ideas with the larger group.
Encourage students to describe the demonstration and share their hypotheses with a family member or friend. Follow up on students’ questions and suggestions in subsequent class meetings if desired.
Ask students to complete an exit slip as their ticket out of the classroom. Write the following sentence stems on the board and have students copy and complete them.
One question I have about today’s demonstration is ____________.
I feel like a scientist when ____________________________.
Lesson written by Kathy Kinsner.