Teaching Brightness of the Sun and Stars – Apparent Magnitude

Teaching about brightness of the Sun and stars? Use these simple activities to explain apparent magnitude. Fortunately, all you need is a flashlight!

Ms. Sneed Teaches About Brightness of the Sun and Stars

Our favorite fourth grade teacher pulled three flashlights out of her cabinet. Then she switched them on and off.

“Hey,” asked her former student teacher, “what are you doing?”

“Just testing these flashlights for our next space science activity,” said Ms. Sneed. “You’ll need them to teach NGSS 5-ESS1-1:

Support an argument that the apparent brightness of the Sun and stars is due to their relative distances from Earth.

Mr. Grow, now a fifth grade teacher, nodded his head. “Ah-ha, apparent magnitude. So how does this activity work?”

“Simple. First, you send one student with a flashlight all the way down the hall. Second, you position another near the other students in the class. Third, you switch off the lights in the hall. Obviously, the closer flashlight appears brighter. Finally, in a second activity, kids compare flashlights of two different sizes at the same distance.”

“You’re right. That is super simple.”

Using Scientific Practices to Draw Conclusions

Ms. Sneed walked across the room and grabbed a few papers off of her desk. “Because of its simplicity, you can also use this lab to reinforce science practices.”

As she spoke, the teacher laid a page on the table in front of Mr. Grow. “Here you see the basic experiment for comparing brightness of the Sun and stars. First, kids ask a question. Then they hypothesize. During the flashlight activity, they record data. Finally, they draw a conclusion.”

In this experiment, students learn about apparent magnitude. Using flashlights, they compare the brightness of the Sun and stars.
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“But my students already know how to do this,” Mr. Grow began.

Identifying Variables in the Brightness of the Sun and Stars Experiment

“Um-hmm. And that’s why you’ll use this.” Ms. Sneed slid another paper on top of the first.

“Your students can take the next step. Initially, they’ll identify variables related to the brightness of the Sun and stars experiment. They’ll list independent, controlled, and dependent variables. Then they’ll use critical thinking to consider ways to strengthen experimental design.”

When kids experiment with brightness of the Sun and stars, they can list variables and tell how to strengthen experimental design.

“Awesome,” Mr. Grow replied. “Definitely they need to work on this.”

Debriefing the Brightness of the Sun and Stars Experiment

“Furthermore,” Ms. Sneed continued, “you can use these questions to debrief. Actually, I’ve used this page as a guide for debriefing after other experiments too. Very powerful.”

After finishing the lab on apparent brightness, use these questions to debrief. Purpose, hypothesis, experimental design, observations, and conclusions are querried.

Slowly, that famous teacher smile spread over Mr. Grow’s face. “Simple, yes. Simply awesome.”

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