Ask kids to explore patterns of day and night with elapsed time. This sharpens an important math skill. What’s more? They’ll find evidence of Earth’s rotation and orbit around the Sun.
Mr. Grow Teaches Elapsed Time of Daylight Hours
Our favorite fifth grade teacher sat at his computer and gazed at the screensaver. Although he looked at it every day, he never tired of the daylight map. Furthermore, his students benefitted from its ever-changing shape.
“Better get down to business,” Mr. Grow told his mentor, Ms. Sneed. “More space science activities! This week, I’m continuing to teach NGSS 5-ESS1-2, in which kids find evidence of Earth’s orbit.” He read the standard aloud:
Represent data in graphical displays to reveal patterns of daily changes in length and direction of shadows, day and night, and the seasonal appearance of some stars in the night sky.
He opened a file and invited Ms. Sneed to look on. “This day and night resource looks promising,” he said.
Background on Earth’s Rotation and Revolution
Slowly, they scrolled through the lesson plans. “After kids explore patterns of day and night,” he explained, “they will make connections to astronomy concepts. First, the Earth rotates on its axis every 24 hours. Second, it revolves around the Sun every 365 days.”
Ms. Sneed giggled. “Don’t those seem a little primary?”
Mr. Grow nodded. “Sure. But you taught me not to assume that my kids know things. And they definitely need to understand those concepts before diving deeper.”
“You are so right,” his mentor agreed. “I see that the next concepts are solstices and equinoxes.”
“Yes. This set of activities actually focuses on the December solstice.”
Learning About Elapsed Time
Mr. Grow scrolled to the next page. “Before they begin, kids need to understand elapsed time. Although they’ve done this before, I like this process. As kids begin, they add minutes, hours, and then minutes again. When they understand that, they can add hours and minutes.”
“I love the way this activity integrates math and science,” said Ms. Sneed. “And we both know how much kids need to practice this math skill!”
Figuring Elapsed Time for Day and Night
“Okay,” Mr. Grow said as he scrolled farther, “here’s the meat of the project. Kids will complete four tables: two for early December and two for late December. They will compare patterns of day and night for two locations: Chicago (USA) and Hobart (Australia). Both are located at 42 degrees latitude – Chicago in the northern hemisphere, and Hobart in the southern.”
Day and Night in Early December
The pair studied the tables. “Actually, this seems straightforward,” said Ms. Sneed. “Scroll down to the answer keys.”
“Ah, I see patterns of day and night. At the beginning of the month, elapsed time for daylight decreases in Chicago. Conversely, it increases in Durham.”
“Not only that,” Ms. Sneed added. “Kids will notice that Durham is getting more hours of daylight than Chicago.”
Day and Night in Late December
Next they looked at the late December answer keys.
“Hey!” Ms. Sneed exclaimed. “Look at this! From December 16th through 25th, Chicago is stalled out at nine hours and eight minutes of daylight. Then days become longer and nights become shorter. But just by a little bit. The seasons are changing.”
“And take a look at Hobart in late December,” said Mr. Grow. “Although the elapsed time increases just a little on December 18th, it gets stuck at fifteen hours and twenty-one minutes of daytime for a week. Then, slowly, it begins to decrease.”
Analyzing Elapsed Time and Patterns of Day and Night
“When kids finish their calculations,” said Mr. Grow, “they graph elapsed time for both cities. Additionally, they can collect data for their own location. Hey, this might make a good year-long station in my room.”
Ms. Sneed smiled. “I can see the wheels in your head turning,” she said.
