Constructing Explanations – Sure Ways to Do It

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Constructing explanations in science trips kids up. After all, how can you explain complex phenomena? Try these surefire ways to do it. First, ask them to observe relationships. Second, change one variable – and name all of them. Third, use evidence. Fourth, describe the phenomenon. And finally, support it with explanations.

Constructing explanations in science requires kids to explain a phenomenon and support it with evidence.

Ms. Sneed and Mr. Grow Discuss Constructing Explanations

Once again, our favorite fourth grade teacher sat at the side table with her mentee. After taking a deep breath, she began. “Okay. We’ve already discussed more than half of the NGSS science practices. First, we talked about testable questions. Second, developing and using models. Then we moved on to investigations. And most recently, we talked about data and then mathematics in science. Today, we’ll talk about constructing explanations.”

“For some reason,” said Mr. Grow, “that sounds a lot like the Common Core State Standards. You know, the ELA standards that ask kids to construct responses.”

“Actually, this science practice is a lot like that. After kids observe relationships, they must explain phenomena. And, as a matter of fact, they have to support their explanations with evidence.”

The Sixth Science Practice, Constructing Explanations

Ms. Sneed referred to the NGSS science practices. “Before we begin, let’s review the standard. I’ll paraphrase it: Constructing explanations uses evidence that specify variables.”

“Aha, I heard the word variables. So we are specifically talking about investigations.”

“Right. This practice tells us how kids should explain the results of experiments.”

An Example: Speed and Energy

Ms. Sneed opened her laptop. On it, already pulled up, Mr. Grow could see a speed and energy unit. “Before our meeting,” the mentor said, “I selected this set of activities to help you understand.”

“I remember it from my student teaching days,” said Mr. Grow. “The sequence begins with a review of types of energy.”

“Right. Then kids launch into a series of labs. We’ll use them to discuss how to teach this science practice.”

1. Observe Relationships

Ms. Sneed scrolled to the page with the second lab. “In this lab kids investigate transfer of energy. First, they rub their hands together – gently at first, then vigorously. Second, they rub their pencil – slowly and quickly. Same with a metal hanger.

“In a short time, they can observe several relationships. Of course, rubbing quickly requires more energy. And that greater amount of kinetic energy generates more heat.”

Ms. Sneed paused and smiled. “And that, in a nutshell, is what they’re supposed to learn in this set of activities. However, let’s remember, that we also want them to construct explanations.”

For constructing explanations in science, kids must first observe relationships. In this lab, kids observe that greater kinetic energy results in more heat energy.
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Change Just One Variable

Ms. Sneed scrolled to the next lab. “As you noticed, kids need to work with variables. In this lab, kids build balloon launchers. Then they launch a small object. Everything remains the same – the launcher, the item, the temperature of the room, etc. Only one thing is varied: the amount of tension.”

“Ah, independent and controlled variables,” Mr. Grow said.

“Right. Many controlled. Only one independent: the tension. To truly explain, kids need to recognize this.”

“But it’s not on the lab sheet.”

Ms. Sneed nodded. “Right. That’s where the teacher comes in. As we work on labs, we have to consciously discuss these things with our kids. Actually try to make it a habit of mind.”

Mr. Grow nodded, deep in thought.

In each experiment, only one variable should be manipulated. Here, for example, kids use a balloon launcher to shoot a small object. Only the amount of tension is varied.

Name All Variables

Now Ms. Sneed scrolled to the next lab. “Let’s talk about this a little more. If you remember, in this lab, kids use a spool racer. Again, they manipulate the tension. This time, they can quantify it by counting the number of times they wind it.”

“So the number of times is the independent variable,” said Mr. Grow. “But it’s not on the lab sheet. So as the teacher, I need to discuss it.”

“Yes, definitely. In addition, I suggest writing it on the board. And for more reinforcement, have kids copy it onto the back of their lab sheet.”

“Of course we’ll need to name the controlled variables as well. I suppose those include the spool racer itself, the surface, and the person winding it. However, I’m sure kids would mention other variables, like the humidity.”

“Now you’re getting the hang of it. Additionally, distance traveled is the dependent variable.”

Now Mr. Grow was smiling. “And I discuss that too.”

“Every single time,” Ms. Sneed replied. “Although it seems like you’re beating it into their heads, kids need it. Repetition is our friend. After all, they cannot truly construct explanations without naming variables.”

To prepare kids for constructing explanations, ask them to name the controlled, independent, and dependent variables.

2. Collect Evidence to Construct Explanations

Next, Ms. Sneed scrolled to a lab with cars and a racetrack.

“One of my favorites,” Mr. Grow commented. “And in my recollections, the car positioned at the steeper angle always won.”

“Evidence,” Ms. Sneed replied. “That’s our next topic for discussion. In this lab, kids conduct three trials. When they explain that greater potential energy results in greater speed, they have three pieces of evidence to back it up.”

As kids experiment, they collect evidence. Here, they send two cars down a track - one at a greater angle. They conduct three trials, and the results can be used as evidence.

3. Describe the Phenomenon

After Ms. Sneed scrolled to the next lab, she looked at Mr. Grow. “Sorry,” she said. “We need to talk about one more thing that’s not on the lab sheet. That’s how to describe the phenomenon.”

The new teacher sighed. “Okay. Let’s hear it.”

“Let’s use this lab as an example. Certainly you remember it.”

Mr. Grow sniggered. “Sure, like I could forget a classroom full of kids armed with paper footballs.”

“Ah, you do remember.” Ms. Sneed grinned. “At the end kids tell whether a gentle or forceful flick requires more energy. What if, instead, I asked them to describe the observed phenomenon.”

At that, Mr. Grow looked uncomfortable. “Uh… Maybe they could say something like ‘Greater force makes the football fly farther’?”

“That’s a start. Can we make a broader generalization?”

“Uh… Greater kinetic energy causes greater speed?”

“You’re getting it! Whenever your class conducts an experiment, work with them to refine their claims. It’s an additional habit of mind that will help kids when constructing explanations.”

When constructing explanations in science, kids must first make a claim. For example, when explaining paper footballs, they may say that greater kinetic energy causes greater spped.

4. Construct Explanations – Claims and Evidence

Suddenly, Mr. Grow sat up straight. “Hey! That rings a bell! Claims and evidence. Again, just like in the Common Core. When I do my next lab, I’m going to use those terms. They’re simple and understandable.”

Ms. Sneed nodded as she scrolled to the next page in the speed and energy file. “On this page, the claim is written at the top.” She read it aloud:

Energy cannot be created or destroyed. Instead, it is transformed from one form to another.

“Oh, I see. On this sheet, kids provide six different pieces of evidence to support that claim.”

“Right you are. More practice.”

To prepare for constructing explanations, kids need to practice providing evidence as support.

Enjoy Teaching Science

Once again, Mr. Grow looked confused. “Wait, I don’t get it. This afternoon, we discussed an entire set of speed and energy activities. During that time, we talked about a whole bunch of strategies for constructing explanations. But never once did we actually do it!”

“Rome wasn’t built in a day,” Ms. Sneed responded. “At the beginning of the school year, kids aren’t ready to construct a thorough explanation. Today, I helped you see what kids need during every investigation. Then, when they’ve practiced this enough, they’ll be able to write a succinct claim and support it with plenty of evidence.”

Mr. Grow rolled his eyes. “And they’ll sure love that.” From experience, he knew kids resisted writing in paragraphs.

Ms. Sneed nodded. “No one ever said that kids need to write a paragraph every time they finish a lab. Instead, they can practice bit by bit. Additionally, they can discuss it. Here, the idea is to prepare them for the end game. Not to punish them with lengthy responses.”

Now Mr. Grow sighed. A small smile spread across his face. “Knowing that I am reinforcing the standards without pain and punishment makes me enjoy teaching a lot more.”

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