Tracking Shadows (Lesson 3) “The Shadow Story”

Focus Question: What can the apparent motions of the Sun and the length of shadows at different times of day and different times of year tell us about the motion of the Earth?

Stonehenge: How did the people of ancient England know where to put the stones for Stonehenge (4000 years ago)?

In which direction does Earth’s axis point?

Approximate Distance to Polaris: 434 Light Years 2,386 Trillion Miles

Setting up the SEM Board for Inquiry 3.1 “North” = Front of Room

Data Collection for 3.1 Have your Sun “rise in the East” and “set in the West” 13 different shadows (6 am to 6 pm) Keep the string taught (no slack)

Acer’s Shadow Period 1:

Acer’s Shadow Period 2:

Acer’s Shadow Period 4:

Sundials: In which direction should a sun dial be positioned?

Big Ideas of Inquiry 3.1 The Sun appears to rise in the East(ish) and set in the West(ish). When the Sun is lower on the horizon the shadows are longer (morning and evening), when the Sun is higher in the sky the shadows are shorter (solar noon = highest/shortest shadows). Since we are North of the Tropic of Cancer the Sun is never directly over our head. The Sun takes a “Southerly Path” across the sky. The apparent path of the Sun across the sky proves that the Earth rotates (spins) in a counter clockwise direction as seen from above.

Big Ideas of Inquiry 3.3 The Sun appears to take a higher path across the sky in the summer and the Sun appears to take a lower path across the sky in Winter. The only way in order for this to happen is if the Earth is tilted.

Big Ideas of Inquiry 3.3.5 The Earth needs to rotate and tilt in order to make the patterns of shadows we observe. The movements of shadows on a daily basis show the rotation of the Earth (Spin = Day and Night). The pattern of shadows on a seasonal basis (long in winter, short in summer) show the tilt of the Earth (Tilt = Seasons).

Lab set up for Inquiry 3.4 Do your best to make the “Sun” shines directly on the widest part of the Earth. (The “normal” set up will not work.) This WILL NOT be on the equator for this inquiry.

Big Ideas of Inquiry 3.4 When the Northern Hemisphere is pointed toward the Sun the shadows are shortest in the Northern Hemisphere (summer) and the shadows are longest in the Southern Hemisphere (winter). When the Southern Hemisphere is pointed toward the Sun the shadows are longest in the Northern Hemisphere (winter) and the shadows are the shortest in the Southern Hemisphere (summer).