# Investigating annual daylight patterns

Students will learn about daylight. They will collect data on sunrise and sunset in the town or city where they live.  They will understand the data pattern and offer a hypothesis about  the reasons that the amount of daylight varies during the year.

## ​Objectives

Students use technology tools to enhance learning, increase productivity, and promote creativity.

## Learning Outcomes

• Students will collect real data about sunrise and sunset times for their town or city.
• Students will look for a pattern in the amount of daylight during the course of a year.
• Students will write explanations for the daylight pattern they observe.
• Students will view an online demonstration to learn the reasons that the amount of daylight varies during the year and write a detailed scientific explanation for the variation in daylight.

## Lesson procedure

### Introduction

Daylight has a powerful affect on all life on our planet. How much do you know about daylight and the affect it has on our lives every day?

Here are some examples.

• What time did the sun rise today?
• Does the sun always set and rise at the same time every day? Does it rise and set at different times in the winter and summer?
• What do you think determines the amount of daylight we have each day?
• If the earth turns all the way around its axis every 24 hours, then why are some days longer than others?
• How do you think these changes in daylight are related to the seasons?

In Step 1 of this lesson, found in the handout, you are going to look at actual sunrise and sunset times for your town or city to see if you can find a pattern in the amount of daylight during the year. You will collect your data in an Office Excel 2007 spreadsheet and create a chart to help you identify the pattern. You will then write an explanation of  the reasons you think the amount of daylight varies throughout the year.

In Step 2, also found in the handout, you will work to understand scientifically the reasons there is a pattern in the amount of daylight over the course of the year. You will view an online demonstration that shows how and why the amount of daylight changes from season to season and then write an explanation about what you have learned.

### Teacher Tips

• #### Demonstrate in 3D

Ask the students to use a model of the Earth and Sun and a flashlight to describe how the Earth’s rotation around the sun affects the seasons.

• #### A different spin on sunlight

In some towns and cities in Iceland, the summer brings days with 18-24 hours of day light and the winter brings 18-24 hours of darkness. Ask students how they think it would affect their sleep. How would they spend their winter days?

### Student activity

Note teachers: Please download the student activity handouts located in the sidebar under Software and Materials Needed, for additional details about the main activities for this lesson plan.

## Conclusion

Ask students to present their reports to the class in teams or on their own.

Assess students' work based on the following criteria:

Step 1: students can be assessed on the accuracy of their data collection and the creation of a chart from their data. Students should use accurate scientific and mathematical terms when describing the patterns they see.

Step 2: students should be evaluated on the responses to the questions after they have viewed the online demonstration.

## Lesson extension activities

Ask students to look up sunrise and sunset data for other locations on earth to verify the accuracy of the online demonstration.

Ask students to read information on Daylight Saving Time around the world and study debates about extending Daylight Saving Time. Ask them to stage a live debate on the issue.