Imagine you are standing in a farm field in central Illinois. The land is so flat you can see for miles and miles. On a clear day, you might see a grain silo 20 miles away. You might think to yourself, it sure is flat around here. If you drive one hundred miles to the south, the landscape changes. In southern Illinois, there are rolling hills. Why do you think this is? What could have caused these features? There are no big rivers that may have eroded and deposited this material. The ground is capable of supporting grass and trees, so wind erosion would not explain it. To answer the question, you need to go back 12,000 years. Around 12,000 years ago, a giant ice sheet covered much of the Midwest United States. Springfield, Illinois, was covered by over a mile of ice. Its hard to imagine a mile thick sheet of ice. The massive ice sheet, called a glacier, caused the features on the land you see today. Where did glaciers go? Where can you see them today? Glaciers are masses of flowing ice.

Question: "What covered Illinois 12,00 years ago?"

Answer: "A sheet of ice at least 1 mile thick that spanned across the Midwest"

Response: yes

The mighty fane, with its three massive towers, rises majestically over the red roofs of the town. Its most striking feature is the great Norman screen, running up without buttresses or projections to the parapet and hiding the bases of the square, richly decorated towers of the west front. The plain centre of the screen is the work of Remigius, the first bishop. The rest of it is relieved with rich arcading of Late Norman and Early English periods. The wooden spires which crowned the towers were removed in 1807. In 1192 Hugh of Avalon determined to rebuild the Norman building of Remigius, which an earthquake had shaken. To him we owe the choir and eastern transept. His successors completed the western transept and began the west end of the nave. So much money had to be spent in rebuilding the central tower, which fell in 1239, that the canons could not rebuild the nave entirely, but had to incorporate the Norman end by Remigius. Unfortunately the axis of the west front does not correspond to that of the nave, which is too wide for its height. The low vaulting is a serious defect in the choir built by St. Hugh, but of the superb beauty of the Angel Choir, which encloses his shrine, there can be no doubt. In its richness of sculpture it is one of the masterpieces of Gothic architecture in England. The interior of the cathedral is remarkable for the harmony of its style, which is Lancet-Gothic, and the dim lighting of the nave only adds to its impressiveness.

Question: "What is the issue with the nave and why is the axis of the west front conflicting with it?"

Answer: "The nave had to be rebuilt after 1239 and the west front is too wide for the nave's height"

Response: yes

"What goes up must come down." You have probably heard that statement before. At one time this statement was true, but no longer. Since the 1960s, we have sent many spacecraft into space. Some are still traveling away from Earth. So it is possible to overcome gravity. Do you need a giant rocket to overcome gravity? No, you actually overcome gravity every day. Think about when you climb a set of stairs. When you do, you are overcoming gravity. What if you jump on a trampoline? You are overcoming gravity for a few seconds. Everyone can overcome gravity. You just need to apply a force larger than gravity. Think about that the next time you jump into the air. You are overcoming gravity for a brief second. Enjoy it while it lasts. Eventually, gravity will win the battle.

Question: "Can a person overcome gravity?"

Answer: "Yes, by jumping up into the air or climbing stairs"

Response: yes

Gravitational Potential Energy is affected by position. Like the leaves on trees, anything that is raised up has the potential to fall. It has potential energy. You can see examples of people with gravitational potential energy in 1.5 Figure below. Gravitational potential energy depends on two things. It depends on its weight, because a large falling rock can do more damage than a leaf falling from a tree. It also depends on its height above the ground. Like the skateboarder, the higher the ramp, the faster he will be going when he reaches the bottom. Like all energy, gravitational potential energy has the ability to do work. In this case, weight has the potential to deliver a force. More important for us is that it has the ability to cause change. What kind of change you may ask? Gravitational potential energy has the ability to cause motion.

Question: "Name two examples of the effect of gravitational potential energy that are given in the paragraph."

Answer: "Leaves change color, skateboarder falls"

Response:
no