Homework #4. Axis of rotation. cold. hot. sun moderate. Bemine. cold

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1 ID 102 Homework #4 Name 1. Why is it warmer (on the average) in Auburn in July than it is in Auburn in January? xplain your reasoning. (Draw a diagram if that will help!) Although the arth is closer to the un during January, the winters in the northern hemisphere are due to the angle of the sun light hitting the arth. Near the equator and in the southern hemisphere, the light rays from the sun approach the arth at almost 90 degrees. This means that the concentration of solar energy per square meter is at a maximum. During the winter in the northern hemisphere, the sun light strikes the surface at a shallower angle. The same amount of sunlight is spread over a larger surface area or one could say that there is less light per square meter of surface. Less solar energy means that the northern hemisphere is colder during this time. 2. A new planet has just been discovered in a distant galaxy! We have called it Bemine. It appears that Bemine rotates around an axis as illustrated in the diagram below. Where you think the warmest part of Bemine will be? How about the coldest? Why? (Assume the distance to its sun is the same as the arth s and the greatest diameter through Bemine is about the same as the arth s diameter.) Axis of rotation sun moderate cold Bemine hot cold The major concept in this answer is that the angle of the surface would determine the temperature. urfaces that are most perpendicular to the incoming light will be the hottest. The poles would be very cold because they are parallel to the light rays. The high temperatures on right side are due to the rotation of the planet around its axis. Bemine would rotate around its axis in the same way the arth does, so it would just be night on that side of Bemine. The animations you used in both the Phases of the Moon module and the eason module were created by the one and only, Keith Clay. ometimes another perspective can help you understand an idea. To help us understand the phases of the Moon go to the following University of Nebraska web site entitled Lunar Phase imulation :

2 As you open the Lunar Phase imulation, you will notice the check boxes in the lower center of the web page. Click the following items: show phase panel show observer show lunar landmark do not click on show angle show time tickmarks The animation starts with a New Moon. Notice that the Moon is between the arth and the un at this phase of the Moon. Rarely the Moon is directly between the arth and the un and we see a solar eclipse. Most of the time, although the Moon is between the arth and the un, the Moon is not in the same plane as the arth and the un and there is no eclipse. In the lower right part of the web page is a figure (similar to the one below) that shows our perspective of the un and the Moon. This is the type of view that early observers of astronomy had when they thought the arth was the center of the universe. As you change the time as a part of the simulation, the un and Moon will appear to orbit the arth. Of course, only the Moon orbits the arth, but from our perspective, it appears everything orbits us. The large diagram in the middle of the page shows the real situation. Click on hour + to move the time of day to 6:00 PM (sunset). In the diagram in the lower right, the un is shown as a yellow circle and the moon is a dark gray circle. Once the time is at 6:00 PM, notice the position of the un and Moon in the diagram on the lower right. un Click on day + to advance the scene to the next day at the same time. Click this button five times and note on the figure on the previous page and in writing in the space below

3 how the positions of the Moon and the un have changed or not changed at the same time of day. With the un fixed at sunset each day, the Moon will be farther and farther to the east each day. We recommend playing with this animation to see a different type of animation for the phases of the moon. When the Moon looks like this draw the position of the un, arth, and Moon in the space below: When the Moon looks like this draw the position of the un, arth, and Moon in the space below:

4 How much of the Moon is being illuminated by the un when the Moon appears like the illustration below? 50 % of the moon is always illuminated, except during eclipses o, explain why we see the Moon this way. We are seeing half of the illuminated part of the moon, so we see ¼ of the moon illuminated waxing or waxing waxing or How could you tell the difference? Waxing moon s are illuminated on the right side and moon s are illuminated on the left side Is the following Moon, waxing or? (it is a gibbous) For each of the Moons below, determine the position of the Moon, arth, and un, the phase of the Moon, and what the Moon would look like 7 days later:

5 positio n of un, Moon, and arth waxing or name for this phase what will the Moon look like 7 days later? Waxing Waning Waxing Neither waxing or quarter gibbous crescent full Full Crescent Quarter-gibbous quarter The following statements are either true or false. If the statement is true, defend your choice in the space below. If the statement is false, state why the statement is false. 1. A waxing gibbous moon phase will be a few days before the full moon phase. True 2. When the Moon appears as it does below, it is possible to have a lunar eclipse: True

6 3. The time of day we expect to see the following phase of the moon is in the early morning, such as 5 or 6 AM. False- the moon is illuminated on the right side meaning that it is a waxing moon. This means that the moon will be behind or to the east of the sun. At 5 or 6 AM the sun will appear in the east. The moon would be below the horizon, so we could not see the moon at that time of day.

7 Planet Keith below rotates around its N- axis and orbits the sun. The position of Planet Keith is shown at two times during the year. Planet Keith s rotational axis points directly at the sun and north is always pointed toward the sun. a) Will Planet Keith have seasons? xplain your logic. No seasons if the rotational axis is always pointed at the sun, it would be summer in the northern hemisphere and winter in the south all the time. Probably near the equator would be the only place one could live. b) Will Planet Keith have day and night? xplain your logic. Not as we know it. The sun would shine on the northern hemisphere all the time and there would be no sun on the southern hemisphere, so no days and nights in one place.