Presentation on theme: "SCIENCE LITERACY Fourth Grade: Unit 2 Force and Motion."— Presentation transcript:
SCIENCE LITERACY Fourth Grade: Unit 2 Force and Motion
What I SeeWhat I ThinkMy Ideas Eg: I see a large area of blue water. This place is on a coast of the ocean or an island. Probably an island because the water is dark blue and looks deep.
In the Pacific Ocean, thousands of miles away from the nearest population center, lies Easter Island, a strange and mysterious place famous for what happened there many years before and what kind of evidence has been left behind. The island, called Rapa Nui (Rap-a-Nu-I) in the local language, is the most isolated inhabited island on Earth. It got its English-language name from a Dutch captain who landed there on Easter Sunday in The captain found a very hilly, palm-covered island with scattered villages and many caves that lead to outcrops of volcanic rock. From this rock was quarried huge structures called Moai. (Mo-I) The Moai were carved statues made from giant rocks that dotted the coastlines, as if guarding the island's people from intruders.
Historians still can't agree on where the island's original people came from, although most people think that they came from somewhere else. Did they sail from Chile, thousands of miles to the east? Did they sail from Hawaii or a Polynesian island, thousands of miles to the west or northwest? No one really knows for sure, although many people have evidence for their theories, including similarities to both Chilean and Polynesian cultures. There were two distinct tribes on the island, the Ha-nau-a-epe, known as the “long ears”, and the Ha-nau- mo-moko, known as the “short ears.” All of the Moai were carved with long ears, which makes historians believe that the short ears were slaves of the long ears and made to build the statues. After the massacre of the long ears by the short ears in the 1600s, no other statues were carved.
As for the moai, these tall, many-ton stone carvings present a scientific mystery. There are a total of 887 Moai on the island, though over 400 were found unfinished in the volcanic quarry where they were carved. The Moai are anywhere from six feet to thirty three feet high and seventy of them have hats or elaborate hair weavings. Many show evidence of being painted of brilliant colors. Historians think that the inhabitants of Easter Island built and transported the giant stone carvings between 1000 and 1600 A.D. But how did they do it? What methods would these natives have used to move and erect the huge statues? And why did they do it? Of the 887 moai located on the island, only 288 of those were moved; the rest were either still in the quarries or were en route to the cliff top watch locations of the others. Most of the Moai face inland, though many are lined up near the ocean. They overlooked the villages and fields of the native people.
You are members of a historical expedition to Easter Island to help solve the mystery of the Moai. As members of the historical expedition, your challenge is to design a way to move and erect the Moai as the islanders may have done. The only resources you may use are the same ones the ancient islanders would have: Ropes woven from palm and cane Wedges made from wood and stone Wood trunks and planks from palm trees Manpower Digging tools like shovels and pick axes
Unit 2 Knowledge Rating Scale WordDefinition What I Know About It Examples Gravity It makes things thrown in the air come back to Earth Friction Trying to move a heavy box across carpet Force Energy that causes motion, usually a push or a pull Motion Resistance
Unit 2 Moai Movement Plan Plan to move Moai Tools needed: How it will be done: Plan to Stand Moai Upright Tools needed: How it will be done: Word Bank: gravity resistance motion force friction
Unit 2 “In June of 2014, our teams of historians made a journey to Easter Island. Once there, we found …”
Unit 2 Resistance is any force that opposes motion. What are some forces that make various objects (cars, roller skates, marbles, baseballs, airplanes, people, water) slow down or stop? How does friction cause resistance? What would happen if there were no resistance to moving objects? What are some ways to lessen resistance? What are some ways the Easter islanders used to work with resistance? What could have been some resisting forces on the island?
Historians think the Moai that were moved could have been transported by several methods. Some may have been moved using wooden logs from the native palm trees as rollers. The huge slabs of stone were laid across the rollers and pushed and pulled over ground that had been cleared and smoothed, much like a dirt road. Using a series of rollers and ropes, the Rapa Nui pulled from the front and pushed from the back to get the large stones from the quarries to the cliffs.
Another method may have been to “walk” the Moai across the smoothed terrain to their cliff top locations. After erecting the statue as it left the quarry, the islanders used a series of ropes looped around the statues. Then men on both sides could have pulled back and forth alternately on the ropes to shift the rock a step at a time.
After the statues were in place, it is possible that the islanders used levers to hoist the statues off the ground at an angle and secured them with ropes. They dug a trench in front of the statues at the base, then built stone or dirt ramps underneath to push the moai into an upright position. As the Moai rose, ropes were pulled to move the statue forward and upright into the trench so it could not topple backward. Once upright, the trench was filled in to secure the statue and give it a firm base.
Historians now think the Moai were built for religious or ceremonial reasons. They may have had something to do with the religion that the Rapa Nui practiced, that the stones were representative of the spirits of the chieftains and the gods. The stones themselves don't all look alike, but they follow a large handful of patterns. Archaeologists think that the patterns were close to how the Rapa Nui chieftains looked. There have also been human burial sites discovered at the base of the statues. It is believed the statues may represent the chief or other high official buried at the site.
As for the Rapa Nui themselves, they gradually died out, from a combination of in-fighting, slave raiding, and exposure to disease as explorers landed on the island. More than half the population of men and women were taken as slaves to work in the mines of Peru, and the few that were able to return to the island came infected with smallpox and other diseases. These quickly spread to the remaining islanders and caused widespread deaths. Today, very few descendants of those early people live on the island. They try to keep alive their traditions and stories, however, and archaeological efforts in recent years have protected the moai from further destruction.