Susan L. Norwood
How Much Would You Weigh If You Were on the Moon?
Objective: To learn and use division to determine weight on the moon. To teach measurement.
Materials: A variety of objects. A scale.
Procedure: Have the students weigh themselves on a scale. Have the students use division to determine what they would weight on the moon. Have the students weigh a variety of objects using a scale, then determine how much these objects would weigh on the moon. Have the students create their own math word problems. Find out how much the whole class weighs on the earth and how much they would weigh on the moon.
The moon's surface is much different from the earth's. There are no continents or oceans on the moon. The moon is made of rocky material that has been melted, crushed by meteorite impacts and erupted through volcanoes. The moon has a thick crust (60 km) , a lithosphere 960-1000 km) and a partly liquid asthenosphere (100-1740 km). It is possible that there is a small iron core at the bottom of the asthenosphere but this has not been confirmed.
The moon is covered with craters. The word crater comes from the Greek word "cup" or "bowl". The craters are circular holes on the surface. The craters were formed by high-speed impacts from meteors or other interplanetary debris. Craters that are larger than 10 kilometers usually have central peaks, which are hills that have been pushed up by pressure within the moon when the weight of the rocks that were impacted was removed. There are about two or three dozen of these impact basins and the largest is about the size of Connecticut. The craters have been named after famous scientist such as Ptolemaeus and Copernicus. Astronomers believe that the great basins were formed about four billion years ago during a short period of time, afterwards only smaller impacts occurred. The earth, too, would have many craters if it were not for our atmosphere which burns up small pieces of rocks, comets, asteroids and debris by friction. The larger ones can come through, and we do have several meteor craters. The ÿ most famous and first to be discovered is the Barringer meteorite crater, near Winslow, Arizona. The crater is 4,200 ft. across and 60 ft. deep. It is estimated to be between 5,000 and 75,000 years old. Most craters have been filled with water and have become lakes and others have fallen into the ocean. The moon has no atmosphere, even the tiniest bit of dust can cause a crater to form. The earth's craters were erased by erosion due to water and wind. The moon has no air or water to erode a crater away.
Dark patches on the moon are called lowlands or maria from the Latin word mare (meaning seas). Galileo gave them this name when he viewed the moon through his telescope. We know today that they contain no water but the name stuck. Dark lava rocks fill the low basins known as maria. Solidified lava flowed across the lower-lying areas of the moon after the large impact basins were formed. These basins were formed early in lunar history, about 3.2 - 3.9 billion years ago. Maria are concentrated on the near side of the moon and cover about 16 % of the moon's surface. Anorthosires are light rocks that form the light, rugged highlands known as terrae. The lunar highlands were formed about 4.4 - 4.6 billion years ago and cover about 80% if the moon's surface. Since then there has been little activity on the moon's surface with the exception of a few small , sporadic crater-forming impacts. Most of the moons surface is covered with regolith. Regolith is a mixture of rocky debris and fine dust produced by meteor impact. Regolith is lunar soil and is found over the entire moon. Regolith can be up to 26 feet thick on the maria and up to 49 feet on the terrae. About 382 kilograms of rock samples were brought back to earth by the Apollo and Luna programs. These samples have provided scientist with answers to many of the questions they had about the moon. From the samples they learned that the moons rocks are between 4.6 and 3 billion years old. The youngest moon rocks are as old as the oldest earth rocks. Early events that probably affected both planetary bodies can now only be found by studying these moon rocks. The rocks have led us to believe that the moon was formed by the impact theory. This states that the earth collided with a very large object and the moon was formed from the ejected material. This theory also helps to explain why the moon and the earth are locked in synchronous orbit.
The astronauts also discovered that the moon is a very silent and airless place. Without air there is no sound. The sky on the moon is always dark. With no atmosphere and no magnetic field, the moon's surface is directly exposed to solar wind. There is some evidence that hydrogen ions from solar wind have become embedded in the moon's regolith. This lunar hydrogen may be of use someday to man. Though the moon has no atmosphere, there is evidence that what are the characteristics of ice has been detected in the deep craters near the moon's south pole. The stars shine all the time. There is no weather on the moon. No rain, water, clouds, or snow. Days and nights are equal to fourteen earth days long. There is no air to spread the hot temperatures, therefore it is very warm during the day and very cold during the evening. Temperatures above boiling and below freezing can be felt on the moon.
Throughout our history the rise and fall of the tides have been studied by man. The tides are a periodic motion of bays, gulfs and seas. At most shores there are two high and low tides during a twenty-four hour period. This is the same amount of time that it takes the earth to rotate, therefore we experience a high or low tide every 12 hours and 25.5 minutes. Tides are caused by the gravitational pull on the earth and its oceans from the moon and the sun and the rotation of the earth. The moon is the principal cause of the tides because it is much closer. The sun's tidal effect is about half as strong as the moons. The gravitational pull is stronger on the side of the earth that is facing the moon causing a high tide, while simultaneously on opposite side of the earth the gravitational pull is fainter also causing high tides. The phases of the moon also affect the tides. During a full moon and a new moon when the earth, moon and sun all lie in a straight line, the gravitational pull increases causing extremely high and low tides. These tides are known as spring tides. If the moon is at perigee during a spring tide, the tidal ranges will be extremely large. When the moon is in its first and third quarters the sun is at a right angle to the moon. The height of the waves are subject to the opposing forces of the sun and the moon during these times resulting in a minimal range between high and low tides. These tides are known as neap tides. If the moon is at apogee during a neap tide, the tidal range will be extremely small. The gravitational pull that the moon has on the earth is seen more clearly with the oceans but it is also being felt on the land. Most ponds and lakes do not experience tides because the water and the land move or rise simultaneously.
