Tips for Younger Students
1. Prepare students for Mystery Class by doing handson activities
to model how earth tilts on its axis, the rotation of the earth,
and how the earth revolves around the sun. I had my third grade class
draw the equator, north pole, and south pole on balloons. Then they
used the balloons and some flashlights to discover why different
parts the earth may get different amounts of daylight. Do the same thing again at noon. Students should put their feet in the same place as earlier in the day. Work with a partner to trace the new shadow. Ask questions like: How has it changed? Is it longer or shorter? Point to the sun? Is it in the same place as before? How has this affected your shadow? Do this again late in the afternoon. Explain to students that during the different seasons, some places on earth receive more direct sunlight, and some indirect. 3. To "keep track of your stuff" in a selfcontained elementary classroom, keep Mystery Class Data sheets in a three ring binder. The sheets can be removed and given to groups of students to record weekly data or to use during an activity, but they must be returned to the binder at the end of the activity. Use divider tabs to separate Mystery Class locations. If students make predictions, draw conclusions, or find information about the Mystery Class Locations, add it to the binder. 4. Model how to calculate the photoperiod. Some of my third graders got it, some didn't. Working collaboratively has helped. Challenge groups of students to calculate the photoperiod for their assigned location each week, and have them record it on the data sheet in PENCIL, so it can be changed if necessary. (You can calculate each photoperiod ahead of time so YOU can check the math.) Give groups time to make their calculations, then ask them to report the photoperiod they calculated. If it's right, reinforce. If it's not, model and reteach. Look for those teachable moments. For example, one week a group calculated a photoperiod to be 24 hours and 17 minutes, which led to a discussion on reasonable answers. 5. Make a wall graph of the photoperiods of all ten locations, plus your home city, so students can see patterns. Make predictions about which way the lines will go. Ask students to give a reason for their prediction. 6. Identify Northern, Southern, Eastern, and Western hemispheres on a globe. Explain that generally world locations lie in two hemispheres. For example, Florida is in the Western and the Northern Hemispheres. Give students a list of countries. Have them find the countries on a world map, and identify the hemispheres in which they lie. Clarify understanding by using some critical thinking questions and a few nonexamples:
7. To prepare students to draw conclusions about the Mystery Class locations, find the longitude and latitude of your home town. Calculate the photoperiod for a chosen day. Use the Internet of other resources to find other places on earth with the same latitude as your home town. Calculate their photoperiods for the same day you chose earlier. (They should be the same as yours.) Record the longitude, latitude, and photoperiod on PostIt notes. Have students stick the PostIt notes in the appropriate places on a large world map. Do they notice a pattern about where they are located? Do they notice a pattern about the amount of daylight? Do the same thing using the longitude of your home town. What can students conclude about the photoperiods now? If you have tips you'd like to share, please write to Journey North: jnorth@learner.org
