How to Plan Investigations in Science for Kids

Plan investigations for kids in your third, fourth, or fifth grade science class. It’s actually pretty easy! All you need to do is control, compare, measure, and replicate. Read on for two simple examples.

Ms. Sneed and Mr. Grow Plan Investigations

After school, as usual, Ms. Sneed and her student teacher sat at the side table. “So,” she said, “today’s science practice is how to plan and and carry out investigations.”

“Ah yes,” Mr. Grow replied. “This is the NGSS science practice that’s like the scientific method.”

“Right. Let me read it to you:

Planning and carrying out investigations to answer questions or test solutions to problems in 3-5 builds on K-2 experiences and progresses to include investigations that control variables and provide evidence to support explanations or design solutions.

“Hmm. I guess we’re focusing on just the science part of that.”

“Right again.” Ms. Sneed returned her attention to Schedule F of the NGSS. “These bullet points indicate that kids should carry out fair tests. Additionally, they must understand methods and tools for data collection, make observations, and predict what will happen if a different variable changes.”

“All that?” Mr. Grow asked.

“Yes, but much of this overlaps with other practices. We can discuss those later. Today, let’s focus on the fair test.”

Plan Investigations That Control Variables

“In a fair test, variables are controlled, right?”

“Yes,” said Ms. Sneed. “At the beginning of the year, I plan investigations that are super simple. As a matter of fact, for this first one, all kids do is cover one cup of water and leave the other uncovered.”

Mr. Grow snickered. “You’ve mentioned this lab before. And I agree, it’s super simple.”

Ms. Sneed rolled her eyes a bit but smiled. “In this activity, all other variables are controlled. For example, kids use the same cups and water. Not just the same size of cups, the exact same king. Furthermore, the water comes from the same pitcher. Therefore, it’s the same temperature, salinity, etc. These are the controlled variables.”

“Same, same, same,” Mr. Grow commented.

“Yep. Additionally, we use the same type of cover for every group in the classroom. And the same measurement tool: a graduated cylinder.”

When Mr. Grow frowned, she added, “You know, not a measuring cup.”

“I get it,” he said. “Everything must be the controlled, or the same.”

When you plan investigations for kids, help them control all but one variable.
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Plan Investigations That Compare

“I know it’s already obvious,” Ms. Sneed said, ” but when you plan investigations, something must be compared. This is the independent variable.

“Notice how these cups are side-by-side,” the teacher continued. “Even now we’re talking about controls. When we place them like this, the cups get the same temperature, light, humidity, and so on. Comparing is the point of the experiment. However, only one variable is compared.”

“And your’e saying I should reinforce this with the students?”

“Absolutely!” Ms. Sneed laughed. “I drive it into your head; you drive it into theirs.”

Just like the old scientific method, science practices still insist that only one variable is compared.

Include Measurement Whenever Possible

The teacher moved on. “Whenever I plan investigations, I try to include measurement. Sure, quantitative data improves the validity of results. But I have other reasons. In fourth grade, I want my kids to use as many measurement tools as possible. That way, they learn math in science.”

“In this experiment, they’ll use a graduated cylinder,” said Mr. Grow. “What other scientific tools will they use for measuring?”

“Good question. First, they need to use a ruler to measure length. Second, as you said, they use a graduated cylinder to measure volume. Third, they measure mass with a balance scale. While those are my big three, kids can also use a clock to measure time, a protractor to measure degrees, a spring scale to measure newtons, and so on.”

Mr. Grow raised his eyebrows. “Wow, I guess I never would have thought that a clock was a science tool.”

Ms. Sneed nodded. “Keep in mind, too, that scientists use the metric system. Therefore, all of our measurements use that system.”

“Another thing to drill into their heads?” Mr. Grow smiled.

“You bet. And you can see why teaching measurement in math occurs early in our school year.

“I just want to mention one more thing. In some investigations, kid make qualitative observations. For example, do you remember that eutrophication lab?”

Mr. Grow nodded.

“As kids observe the pond water, it’s hard to measure the amount of algae. Therefore, they simply write what they see. However, in the lab set-up, they use a graduated cylinder. Hopefully you see that I try to work in measurement wherever I can. Even if it’s not in data collection.”

When you plan investigations, include measurement whenever possible. Kids should measure to control variables, as well as to gather data.

Replicate, or Repeat

Finally, Ms. Sneed got to her last point. “The NGSS specifically says that kids should consider the number of trials.”

“So we should plan investigations that repeat experiments?”

“Not exactly. Fortunately, our classroom is full of little scientists. Therefore, replication can be achieved in one trial. In other words, many groups do the same lab. Then they share and compare results. As a matter of fact, finding averages, or the mean, is also helpful.”

Mr. Grow sighed deeply. “Wow. Now I see why you use such a simple activity to teach the fair test.” He shook his head and smiled. “Something so complex made easy.”

When you plan investigations, make sure to include replication. Kids need to know that repeating an experiment gives its results validity.

Another Example of How to Plan Investigations

“Real quick,” Ms. Sneed said, “let me give you one more example of how to plan investigations.”

Quickly, she pulled out a file. “In this little lab, kids use different gloves to compare amounts of static electricity.”

This static electricity experiment controls all but one variable, uses super simple measurement, and can be replicated.

Control the Variables

“Once again,” she said, “when we plan investigations, we control all but one variable. In this lab, we use the same circles of paper and balloons.”

“So we could’t use those multi-packs of balloons with different shapes and colors?”

“Absolutely not. All the same shape, size, and color.”

“And,” Mr. Grow added, “we’d need the same number of paper circles, all cut from the same type of paper.”

Compare One Thing

Ms. Sneed smiled. “You’re sure catching on fast! Also, as we discussed before, we plan investigations that compare one variable. What is it here?”

“The glove?”

“Bingo! And from the picture, you can see that kids can actually try several different kinds of gloves. Just so the glove is the only independent variable.”

Plan Investigations with Even the Simplest Measurement

Mr. Grow scratched his head. “Measurement is the next thing to consider as we plan investigations. However, I don’t see any here.”

“Think a little deeper,” his mentor challenged.

The student teacher’s face remained blank, so Ms. Sneed gave him a hint. “What about the balloon?”

“Ah, I guess they could measure the circumference to control the amount of air in each balloon.”

“Yes. And although it’s again super simple, kids measure the number of paper circles that stick to the balloon. Then they count them.”


Again, Mr. Grow nodded his head and smiled. “Fortunately, I can see how to plan investigations that consider the number of trials. In this experiment, multiple groups would do the same experiment. Of course, each group would need to use the same types of gloves.”

Enjoy Teaching

Ms. Sneed handed the static electricity file to her student teacher. “Want to give it a whirl? Now that you know how to plan investigations, you’re ready to use them with the students!”

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