Vocabulary: direct sunlight, Earth’s axis, equator, indirect sunlight, northern hemisphere, North Pole, season, solstice, southern hemisphere, South Pole, summer solstice, winter solstice
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. At what time of day is sunlight strongest – in the early morning (when the Sun has just risen) or at noon (when the Sun reaches its highest point)? At noon when the Sun reaches its highest point.
2. At what time of year does the noon Sun rise highest in the sky? During the summer time.
3. Based on your answers, why is it warmer in summer than in winter? It is warmer in the summer then in the winter because the Earth’s tilt is faced towards the Sun.
Gizmo Warm-up
The reasons for seasons have a lot to do with the angle at which the Sun’s rays hit Earth. To see why, select the PLATE tab on the Seasons: Why do we have them? Gizmo™. The image shows a solar panel (Plate M) facing the Sun. Check that the Axis angle is set to 0˚.
1. Click Fire to release 100 “rays” of sunlight. Look next to “Number of hits” below the plate.
How many of these rays hit Plate M? 100
2. Click Reset. Change the Axis angle to 40˚, and click Fire. How many rays hit Plate M now? 76
3. Which do you think will warm up the plate more quickly? (Circle one.)
A. Direct sunlight (sunlight that hits the plate at a 90° angle)
B. Indirect sunlight (sunlight that hits the plate at an angle of less than 90°)
Activity A:
Sunlight on a plate
Get the Gizmo ready:
Click Reset.
Question: How does the angle of sunlight affect the amount of energy that is absorbed?
1. Form hypothesis: How do you think the angle of the plate will affect how much sunlight hits the plate? The closer the angle is to zero, the more sunlight that will hit the plate.
2. Collect data: Set the Axis angle to -80° and click Fire. Record the Number of hits. Repeat for each angle and fill in the tables below. You can