We're studying adverbs, adjectives, nouns, and verbs in year 3. They need to identify them and put them in sentences.

Growing up in Sioux Falls, South Dakota, a small city surrounded by endless plains, I've found unexpected echoes of home in China's smaller towns — from the warmth of locals in Huaihua, Central China's Hunan province, to the quiet charm of Yangshuo, South China's Guangxi Zhuang autonomous region. With an itch to see more of China's lesser-visited regions, I began planning a trip to the northwest with seven friends — five Americans, one Pakistani, one Zimbabwean, and one Colombian. We bought round-trip tickets from Shanghai to Yinchuan, Ningxia Hui autonomous region, for less than $120 each. From there, we planned to rent a car and drive to Xining in Qinghai, then on to Qinghai Lake, and finally to Lanzhou, Gansu. To make that possible, several of us applied for Chinese driver's licenses, a process that involved translating our US licenses into Mandarin and passing a short test on traffic laws. Within a day, we were licensed. As we piled into two rental cars in late March to begin our eight-day journey, it became clear that this wasn't just a road trip — it was the culmination of our four years in China, the Mandarin we had so diligently studied, and our ongoing effort to contribute to US-China people-to-people relations. Right away, we drew curious reactions. At the Yinchuan airport, taxi drivers offered us rides into the city, only to stare in astonishment when we told them we had rented cars. "You're driving? In China?" one driver asked, visibly surprised. It was a reaction we'd encountered multiple times during our trip, as foreign drivers are rare in China, especially in remote regions. In Yinchuan, we stocked up on snacks and adjusted to the chilly desert air. From there, we headed west, navigating wide highways framed by dramatic landscapes: arid plains, jagged mountains, and occasionally, a herd of sheep crossing the road. The vastness of the Northwest was humbling — and as someone who grew up on the wide-open prairies of South Dakota, it felt oddly familiar. One of the highlights of our trip was camping by Qinghai Lake, the largest saltwater lake in China. A few summers ago, Santiago Solano, one of my classmates from the US, cycled from Xi'an in Shaanxi to Urumqi in the Xinjiang Uygur autonomous region over the course of a month and met many kind strangers along the way. One of them was Geng San, a Tibetan lamb herder who managed a piece of land right next to Qinghai Lake and graciously invited us to camp there. "That's what China is — it's the people. The quiet generosity of an old Tibetan nomad who, years after we first met, still offered us a place to rest on his land," said Solano, who is also part of the group on this trip. But apparently, we underestimated just how cold it would be to camp next to Qinghai Lake in late March. It was deathly freezing. In preparation for the trip, we had ordered two tent kits and eight sleeping bags. However, when the temperature eventually dropped to — 10 C, all of us piled into the cars and turned the heaters on. So much for camping. From Qinghai Lake, we drove to Lanzhou, where we visited many food markets and tried every type of noodle on offer. Since we are college students, we rented a gaming hotel room — something I've only ever seen in China. At night, instead of attending local parties as we had before, we stayed in the hotel and gamed late into the morning. For me, the trip was as much about the journey as it was about the destinations. Driving through Northwest China gave us a unique perspective on the region's natural beauty and its people. At gas stations, shopkeepers greeted us with curiosity and kindness, often offering recommendations for nearby attractions. At roadside carts, we sampled local specialties, grabbing a quick skewer and a mango for the road. And at every stop, we were touched by the warmth and hospitality that make traveling in China so rewarding. As an American who has lived in China for several years, I'm often asked about my experiences here. Trips like this one remind me of the similarities between the two countries, despite their differences. Just as road trips are a quintessential part of American culture, they've become my favorite way to explore China. Whether it's driving through the rolling hills of South Dakota or the deserts of Ningxia, there's something universal about the freedom and camaraderie that come with having complete control over where you end up. Written by Charlie Howes, a 22-year-old American who has lived in China since 2019. He completed his final year of high school at Beijing No 80 High School and is currently studying at New York University Shanghai. He has founded a company in China focused on facilitating US-China trade and plans to continue living in Shanghai long term. He enjoys road trips, cycling around the world, learning languages, and meeting new people.

Cell Theory The microscopes we use today are far more complex than those used in the 1600s by Antony van Leeuwenhoek, a Dutch shopkeeper who had great skill in crafting lenses. Despite the limitations of his now-ancient lenses, van Leeuwenhoek observed the movements of protista (a type of single-celled organism) and sperm, which he collectively termed “animalcules. ” In a 1665 publication called Micrographia, experimental scientist Robert Hooke coined the term “cell” for the box-like structures he observed when viewing cork tissue through a lens. In the 1670s, van Leeuwenhoek discovered bacteria and protozoa. Later advances in lenses, microscope construction, and staining techniques enabled other scientists to see some components inside cells. image Figure 4.3.1 : Structure of an Animal Cell: The cell is the basic unit of life and the study of the cell led to the development of the cell theory. By the late 1830s, botanist Matthias Schleiden and zoologist Theodor Schwann were studying tissues and proposed the unified cell theory. The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells. Rudolf Virchow later made important contributions to this theory. Schleiden and Schwann proposed spontaneous generation as the method for cell origination, but spontaneous generation (also called abiogenesis) was later disproven. Rudolf Virchow famously stated “Omnis cellula e cellula”… “All cells only arise from pre-existing cells. “The parts of the theory that did not have to do with the origin of cells, however, held up to scientific scrutiny and are widely agreed upon by the scientific community today. The generally accepted portions of the modern Cell Theory are as follows: The cell is the fundamental unit of structure and function in living things. All organisms are made up of one or more cells. Cells arise from other cells through cellular division. The expanded version of the cell theory can also include: Cells carry genetic material passed to daughter cells during cellular division All cells are essentially the same in chemical composition Energy flow (metabolism and biochemistry) occurs within cells

THE FIDE LAWS OF CHESS. Introduction FIDE Laws of Chess cover over-the-board play. The Laws of Chess have two parts: 1. Basic Rules of Play and 2. Competitive Rules of Play. The English text is the authentic version of the Laws of Chess (which were adopted at the 93rd FIDE Congress at Chennai, India) coming into force on 1 January 2023. Preface. The Laws of Chess cannot cover all possible situations that may arise during a game, nor can they regulate all administrative questions. Where cases are not precisely regulated by an Article of the Laws, it should be possible to reach a correct decision by studying analogous situations which are regulated in the Laws. The Laws assume that arbiters have the necessary competence, sound judgement and absolute objectivity. Too detailed a rule might deprive the arbiter of his/her freedom of judgement and thus prevent him/her from finding a solution to a problem dictated by fairness, logic and special factors. FIDE appeals to all chess players and federations to accept this view. A necessary condition for a game to be rated by FIDE is that it shall be played according to the FIDE Laws of Chess. It is recommended that competitive games not rated by FIDE be played according to the FIDE Laws of Chess. Member federations may ask FIDE to give a ruling on matters relating to the Laws of Chess. BASIC RULES OF PLAY. Article 1: The Nature and Objectives of the Game of Chess 1.1 1.2 1.3 1.4 The game of chess is played between two opponents who move their pieces on a square board called a ‘chessboard’. The player with the light-coloured pieces (White) makes the first move, then the players move alternately, with the player with the dark-coloured pieces (Black) making the next move. A player is said to ‘have the move’ when his/her opponent’s move has been ‘made’. The objective of each player is to place the opponent’s king ‘under attack’ in such a way that the opponent has no legal move. 1.4.1 The player who achieves this goal is said to have ‘checkmated’ the opponent’s king and to have won the game. Leaving one’s own king under attack, exposing one’s own king to attack and also ’capturing’ the opponent’s king is not allowed. 1.4.2 The opponent whose king has been checkmated has lost the game. 1.5 If the position is such that neither player can possibly checkmate the opponent’s king, the game is drawn (see Article 5.2.2). Article 2: The Initial Position of the Pieces on the Chessboard 2.1 2.2 The chessboard is composed of an 8 x 8 grid of 64 equal squares alternately light (the ‘white’ squares) and dark (the ‘black’ squares). The chessboard is placed between the players in such a way that the near corner square to the right of the player is white. At the beginning of the game White has 16 light-coloured pieces (the ‘white’ pieces); Black has 16 dark-coloured pieces (the ‘black’ pieces). These pieces are as follows: A white king usually indicated by the symbol K A white queen Two white rooks Two white bishops Two white knights Eight white pawns A black king A black queen Two black rooks Two black bishops Two black knights Eight black pawns usually indicated by the symbol Q usually indicated by the symbol R usually indicated by the symbol B usually indicated by the symbol N usually indicated by the symbol usually indicated by the symbol K usually indicated by the symbol Q usually indicated by the symbol R usually indicated by the symbol B usually indicated by the symbol N usually indicated by the symbol Staunton Pieces p Q K B N R 9 2.3 The initial position of the pieces on the chessboard is as follows: 2.4 The eight vertical columns of squares are called ‘files’. The eight horizontal rows of squares are called ‘ranks’. A straight line of squares of the same colour, running from one edge of the board to an adjacent edge, is called a ‘diagonal’. Article 3: The Moves of the Pieces 3.1 It is not permitted to move a piece to a square occupied by a piece of the same colour. 3.1.1 If a piece moves to a square occupied by an opponent’s piece the latter is captured and removed from the chessboard as part of the same move. 3.1.2 A piece is said to attack an opponent’s piece if the piece could make a capture on that square according to Articles 3.2 to 3.8. 3.1.3 A piece is considered to attack a square even if this piece is constrained from moving to that square because it would then leave or place the king of its own colour under attack. 3.2 The bishop may move to any square along a diagonal on which it stands. 3.3 The rook may move to any square along the file or the rank on which it stands. 3.4 The queen may move to any square along the file, the rank or a diagonal on which it stands. 3.5 3.6 3.7 When making these moves, the bishop, rook or queen may not move over any intervening pieces. The knight may move to one of the squares nearest to that on which it stands but not on the same rank, file or diagonal. 3.7 When making these moves, the bishop, rook or queen may not move over any intervening pieces. The knight may move to one of the squares nearest to that on which it stands but not on the same rank, file or diagonal. The pawn: 3.7.1 The pawn may move forward to the square immediately in front of it on the same file, provided that this square is unoccupied, or 3.7.2 on its first move the pawn may move as in 3.7.1 or alternatively it may advance two squares along the same file, provided that both squares are unoccupied, or 3.7.3 the pawn may move to a square occupied by an opponent’s piece diagonally in front of it on an adjacent file, capturing that piece. 3.7.3.1 A pawn occupying a square on the same rank as and on an adjacent file to an opponent’s pawn which has just advanced two squares in one move from its original square may capture this opponent’s pawn as though the latter had been moved only one square. 3.7.3.2 This capture is only legal on the move following this advance and is called an ‘en passant’ capture. 3.7.3.3 When a player, having the move, plays a pawn to the rank furthest from its starting position, he/she must exchange that pawn as part of the same move for a new queen, rook, bishop or knight of the same colour on the intended square of arrival. This is called the square of ‘promotion’. 3.7.3.4 The player's choice is not restricted to pieces that have been captured previously. 3.7.3.5 This exchange of a pawn for another piece is called promotion, and the effect of the new piece is immediate. 3.8 There are two different ways of moving the king: 3.8.1 by moving to an adjoining square. 3.8.2 by ‘castling’. This is a move of the king and either rook of the same colour along the player’s first rank, counting as a single move of the king and executed as follows: the king is transferred from its original square two squares towards the rook on its original square, then that rook is transferred to the square the king has just crossed. 3.8.2.1 The right to castle has been lost: 3.8.2.1.1 If the king has already moved, or 3.8.2.1.2 With a rook that has already moved. 3.8.2.2 Castling is prevented temporarily: 3.8.2.2.1 if the square on which the king stands, or the square which it must cross, or the square which it is to occupy, is attacked by one or more of the opponent's pieces, or 3.8.2.2.2 if there is any piece between the king and the rook with which castling is to be effected. 3.9 The king in check: 3.9.1 The king is said to be 'in check' if it is attacked by one or more of the opponent's pieces, even if such pieces are constrained from moving to the square occupied by the king because they would then leave or place their own king in check. 3.9.2 No piece can be moved that will either expose the king of the same colour to check or leave that king in check. 3.10 Legal and illegal moves; illegal positions: 3.10.1 A move is legal when all the relevant requirements of Articles 3.1 – 3.9 have been fulfilled. 3.10.2 A move is illegal when it fails to meet the relevant requirements of Articles 3.1 –3.9. 3.10.3 A position is illegal when it cannot have been reached by any series of legal moves. Article 4: The Act of Moving the Pieces 4.1 4.2 Each move must be played with one hand only. Adjusting the pieces or other physical contact with a piece: 4.2.1 Only the player having the move may adjust one or more pieces on their squares, provided that he/she first expresses his/her intention (for example by saying “j’adoube” or “I adjust”). 4.2.2 Any other physical contact with a piece, except for clearly accidental contact, shall be considered to be intent. 4.3 Except as provided in Article 4.2.1, if the player having the move touches on the chessboard, with the intention of moving or capturing: 4.3.1 one or more of his/her own pieces, he/she must move the first piece touched that can be moved. 4.3.2 one or more of his/her opponent’s pieces, he/she must capture the first piece touched that can be captured. 4.3.3 one or more pieces of each colour, he/she must capture the first touched opponent’s piece with his/her first touched piece or, if this is illegal, move or capture the first piece touched that can be moved or captured. If it is unclear whether the player’s own piece or his/her opponent’s was touched first, the player’s own piece shall be considered to have been touched before his/her opponent’s. 4.4 If a player having the move: 4.4.1 touches his/her king and a rook he/she must castle on that side if it is legal to do so 4.4.2 deliberately touches a rook and then his/her king he/she is not allowed to castle on that side on that move and the situation shall be governed by Article 4.3.1. 4.4.3 intending to castle, touches the king and then a rook, but castling with this rook is illegal, the player must make another legal move with his/her king (which may include castling with the other rook). If the king has no legal move, the player is free to make any legal move. 4.4.4 promotes a pawn, the choice of the piece is finalised when the piece has touched the square of promotion. 4.5 4.6 If none of the pieces touched in accordance with Article 4.3 or Article 4.4 can be moved or captured, the player may make any legal move. The act of promotion may be performed in various ways: 4.6.1 the pawn does not have to be placed on the square of arrival. 4.6.2 removing the pawn and putting the new piece on the square of promotion may occur in any order. 4.6.3 If an opponent’s piece stands on the square of promotion, it must be captured. 4.7 When, as a legal move or part of a legal move, a piece has been released on a square, it cannot be moved to another square on this move. The move is considered to have been made in the case of: 4.7.1 A capture, when the captured piece has been removed from the chessboard and the player, having placed his/her own piece on its new square, has released this capturing piece from his/her hand. 4.7.2 Castling, when the player's hand has released the rook on the square previously crossed by the king. When the player has released the king from his/her hand, the move is not yet made, but the player no longer has the right to make any move other than castling on that side, if this is legal. If castling on this side is illegal, the player must make another legal move with his/her king (which may include castling with the other rook). If the king has no legal move, the player is free to make any legal move. 4.7.3 Promotion, when the player's hand has released the new piece on the square of promotion and the pawn has been removed from the board. 4.8 4.9 A player forfeits his/her right to claim against his/her opponent’s violation of Articles 4.1 – 4.7 once the player touches a piece with the intention of moving or capturing it. 4.8. A player forfeits his/her right to claim against his/her opponent’s violation of Articles 4.1 – 4.7 .4.9. If a player is unable to move the pieces, an assistant, who shall be acceptable to the arbiter, may be provided by the player to perform this operation. Article 5: The Completion of the Game 5.1.1 The game is won by the player who has checkmated his/her opponent’s king. This immediately ends the game, provided that the move producing the checkmate position was in accordance with Article 3 and Articles 4.2 – 4.7. 5.1.2 The game is lost by the player who declares he/she resigns (this immediately ends the game), unless the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves. In this case the result of the game is a draw. 5.2.1 The game is drawn when the player to move has no legal move and his/her king is not in check. The game is said to end in ‘stalemate’. This immediately ends the game, provided that the move producing the stalemate position was in accordance with Article 3 and Articles 4.2 – 4.7. 5.2.2 The game is drawn when a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves. The game is said to end in a ‘dead position’. This immediately ends the game, provided that the move producing the position was in accordance with Article 3 and Articles 4.2 – 4.7. 5.2.3 The game is drawn upon agreement between the two players during the game, provided both players have made at least one move. This immediately ends the game. COMPETITIVE RULES OF PLAY Article 6: The Chessclock 6.1 ‘Chessclock’ means a clock with two time displays, connected to each other in such a way that only one of them can run at a time. ‘Clock’ in the Laws of Chess means one of the two time displays. Each time display has a ‘flag’. ‘Flag-fall’ means the expiration of the allotted time for a player. 6.2 Handling the chessclock: 6.2.1 During the game each player, having made his/her move on the chessboard, shall pause his/her own clock and start his/her opponent’s clock (that is to say, he/she shall press his/her clock). This “completes” the move. A move is also completed if: 6.2.1.1 6.2.1.2 the move ends the game (see Articles 5.1.1, 5.2.1, 5.2.2, 9.2.1, 9.6.1 and 9.6.2), or the player has made his/her next move, when his/her previous move was not completed. 6.2.2 A player must be allowed to pause his/her clock after making his/her move, even after the opponent has made his/her next move. The time between making the move on the chessboard and pressing the clock is regarded as part of the time allotted to the player. 6.2.3 A player must press his/her clock with the same hand with which he/she made his/her move. It is forbidden for a player to keep his/her finger on the clock or to ‘hover’ over it. 6.2.4 The players must handle the chessclock properly. It is forbidden to press it forcibly, to pick it up, to press the clock before moving or to knock it over. Improper clock handling shall be penalised in accordance with Article 12.9. 6.2.5 6.2.6 Only the player whose clock is running is allowed to adjust the pieces. If a player is unable to use the clock, an assistant, who must be acceptable to the arbiter, may be provided by the player to perform this operation. His/Her clock shall be adjusted by the arbiter in an equitable way. This adjustment of the clock shall not apply to the clock of a player with a disability. 6.3 Allotted time: 6.3.1 When using a chessclock, each player must complete a minimum number of moves or all moves in an allotted period of time including any additional amount of time added with each move. All these must be specified in advance. 6.3.2 The time saved by a player during one period is added to his/her time available for the next period, where applicable. In the time-delay mode both players receive an allotted ‘main thinking time’. Each player also receives a ‘fixed extra time’ with every move. The countdown of the main thinking time only commences after the fixed extra time has expired. Provided the player presses his/her clock before the expiration of the fixed extra time, the main thinking time does not change, irrespective of the proportion of the fixed extra time used. 6.4 Immediately after a flag falls, the requirements of Article 6.3.1 must be checked. 6.5 Before the start of the game the arbiter shall decide where the chessclock is placed. 6.6 At the time determined for the start of the game White’s clock is started.6.7. Default time: 6.7.1 The regulations of an event shall specify a default time in advance. If the default time is not specified, then it is zero. Any player who arrives at the chessboard after the default time shall lose the game unless the arbiter decides otherwise. 6.7.2 If the regulations of an event specify that the default time is not zero and if neither player is present initially, White shall lose all the time that elapses until he/she arrives, unless the regulations of an event specify, or the arbiter decides otherwise. 6.8 A flag is considered to have fallen when the arbiter observes the fact or when either player has made a valid claim to that effect. 6.9 Except where one of Articles 5.1.1, 5.1.2, 5.2.1, 5.2.2, 5.2.3 applies, if a player does not complete the prescribed number of moves in the allotted time, the game is lost by that player. However, the game is drawn if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves. 6.10 Chessclock setting: 6.10.1 Every indication given by the chessclock is considered to be conclusive in the absence of any evident defect. A chessclock with an evident defect shall be replaced by the arbiter, who shall use his/her best judgement when determining the times to be shown on the replacement chessclock. 6.10.2 If during a game it is found that the setting of either or both clocks is incorrect, either player or the arbiter shall pause the chessclock immediately. The arbiter shall install the correct setting and adjust the times and move-counter, if necessary he/she shall use his/her best judgement when determining the clock settings. 6.11.1 If the game needs to be interrupted, the arbiter shall pause the chessclock. 6.11.2 A player may pause the chessclock only in order to seek the arbiter’s assistance, for example when promotion has taken place and the piece required is not available. 6.11.3 The arbiter shall decide when the game restarts. 6.11.4 If a player pauses the chessclock in order to seek the arbiter’s assistance, the arbiter shall determine whether the player had any valid reason for doing so. If the player has no valid reason for pausing the chessclock, the player shall be penalised in accordance with Article 12.9. 6.12.1 Screens, monitors, or demonstration boards showing the current position on the chessboard, the moves and the number of moves made/completed, and clocks which also show the number of moves, are allowed in the playing hall. 6.12.2 The player may not make a claim relying only on information shown in this manner.

Long ago, people from different cultures had stories about how the world began and how humans came to be. These stories are called creation stories. Even though these cultures were different, their creation stories often had similar ideas. Two creation stories that we will explore are one from Native Americans in North America and one from ancient Greece. Both stories talk about bringing light and fire to people. They also have something called archetypes, which are important in creation stories. Archetypes are things that show up a lot in different stories from different times and places. They can be symbols, patterns, or types of characters. Archetypes help us understand that even though cultures are different, they have some things in common. In these creation stories, there are two archetypal figures - the Raven and Prometheus. They represent things like wanting to learn, make progress, and find enlightenment. Both stories show how these figures go against higher powers to give people something good. The Raven and Prometheus are smart, resourceful, and want to make life better for humans. Understanding archetypes helps us see that cultures have things in common. The Raven and Prometheus are symbols that show what it means to be human. By studying and comparing these symbols, we can learn more about what people believe and want, no matter where they come from. The Raven and Prometheus remind us that people always want to learn, make progress, and find enlightenment. In the Native American creation story, the Raven brings light to the world. Long ago, the world was very dark and people had a hard time finding their way. But then, a clever bird called the Raven decided to help. The Raven stole a box that held the sun, moon, and stars from a powerful being. As the Raven flew across the sky, the box opened and filled the world with light. This light helped guide and teach humans. The Raven is seen as smart, resourceful, and a symbol of light. In the ancient Greek story, Prometheus steals fire from the gods on Mount Olympus. Prometheus cared a lot about humans and wanted to help them. Fire was something special that only the gods had, and it represented knowledge, creativity, and civilization. Prometheus brought fire down to Earth secretly because he knew it would make life better for humans. With fire, they could stay warm, cook food, and protect themselves. Prometheus was brave and kind, and he wanted to help humanity. Both the Raven and Prometheus stories have similarities. They are both about giving humans something important that helps them learn and progress. The Raven gave light, while Prometheus gave fire. The Raven and Prometheus are both very smart and clever. They wanted to make life better for people. These stories show us that no matter where people come from, they all have a desire to learn, make progress, and find enlightenment.

The Pleiades, also known as the Seven Sisters, is a famous star cluster located in the constellation of Taurus. It is made up of a group of seven bright stars that are visible to the naked eye in the night sky. The stars in the Pleiades cluster are relatively young, being only about 100 million years old, which is young in astronomical terms. The Pleiades cluster has been observed and admired by cultures all around the world for thousands of years. In Greek mythology, the Pleiades were seven sisters who were pursued by the hunter Orion. To protect them, Zeus transformed them into stars, forming the star cluster we see today. Different cultures have their own stories and legends associated with the Pleiades, making it a fascinating object of study for astronomers and a source of inspiration for artists and storytellers. The Pleiades cluster is often used as a test of eyesight, as people are challenged to count how many stars they can see with the naked eye. Most people can see six or seven stars, but those with particularly sharp vision may be able to see more. The Pleiades is also a popular target for amateur astronomers with telescopes, as the cluster reveals even more stars and details when viewed through a telescope. In addition to being a beautiful sight in the night sky, the Pleiades cluster also serves a practical purpose for astronomers. By studying the stars in the Pleiades, scientists can learn more about how stars form and evolve, as well as gain insights into the structure and composition of the Milky Way galaxy. The Pleiades cluster continues to be an important object of study for astronomers, both amateur and professional, and its beauty and significance will continue to capture the imaginations of people for generations to come. Matariki is the Maori name for the Pleiades star cluster. The Pleiades is a group of stars that can be seen in the night sky, and Matariki is a special time of year when the star cluster is visible in the sky. In Maori culture, Matariki is seen as the beginning of the Maori New Year, and it is a time to celebrate and give thanks for the past year and look forward to the year ahead. So basically, Matariki is related to the Pleiades because it is a special time of year when those stars are visible in the sky and it has cultural significance for the Maori people. The Pleiades star cluster is known by different names in various cultures around the world. Here are some of the names by which the Pleiades are referred to in different countries: 1. Maori culture in New Zealand and Polynesia: Matariki 2. Greek mythology: The Seven Sisters 3. Japan: Subaru 4. Native American tribes: The Dancers or The Little Eyes 5. Inca civilization: Collca 6. Ancient Persia: Parvin 7. India: Krittika 8. Aboriginal Australians: The Seven Sisters or Djulpan These different names reflect the diverse cultural significance and interpretations of the Pleiades cluster in various societies throughout history.

What do an ancient Greek philosopher and a 19th century Quaker have in common with Nobel Prize-winning scientists? Although they are separated over 2,400 years of history, each of them contributed to answering the eternal question: what is stuff made of? It was around 440 BCE that Democritus first proposed that everything in the world was made up of tiny particles surrounded by empty space. And he even speculated that they vary in size and shape depending on the substance they compose. He called these particles "atomos," Greek for indivisible. His ideas were opposed by the more popular philosophers of his day. Aristotle, for instance, disagreed completely, stating instead that matter was made of four elements: earth, wind, water and fire, and most later scientists followed suit. Atoms would remain all but forgotten until 1808, when a Quaker teacher named John Dalton sought to challenge Aristotelian theory. Whereas Democritus's atomism had been purely theoretical, Dalton showed that common substances always broke down into the same elements in the same proportions. He concluded that the various compounds were combinations of atoms of different elements, each of a particular size and mass that could neither be created nor destroyed. Though he received many honors for his work, as a Quaker, Dalton lived modestly until the end of his days. Atomic theory was now accepted by the scientific community, but the next major advancement would not come until nearly a century later with the physicist J.J. Thompson's 1897 discovery of the electron. In what we might call the chocolate chip cookie model of the atom, he showed atoms as uniformly packed spheres of positive matter filled with negatively charged electrons. Thompson won a Nobel Prize in 1906 for his electron discovery, but his model of the atom didn't stick around long. This was because he happened to have some pretty smart students, including a certain Ernest Rutherford, who would become known as the father of the nuclear age. While studying the effects of X-rays on gases, Rutherford decided to investigate atoms more closely by shooting small, positively charged alpha particles at a sheet of gold foil. Under Thompson's model, the atom's thinly dispersed positive charge would not be enough to deflect the particles in any one place. The effect would have been like a bunch of tennis balls punching through a thin paper screen. But while most of the particles did pass through, some bounced right back, suggesting that the foil was more like a thick net with a very large mesh. Rutherford concluded that atoms consisted largely of empty space with just a few electrons, while most of the mass was concentrated in the center, which he termed the nucleus. The alpha particles passed through the gaps but bounced back from the dense, positively charged nucleus. But the atomic theory wasn't complete just yet. In 1913, another of Thompson's students by the name of Niels Bohr expanded on Rutherford's nuclear model. Drawing on earlier work by Max Planck and Albert Einstein he stipulated that electrons orbit the nucleus at fixed energies and distances, able to jump from one level to another, but not to exist in the space between. Bohr's planetary model took center stage, but soon, it too encountered some complications. Experiments had shown that rather than simply being discrete particles, electrons simultaneously behaved like waves, not being confined to a particular point in space. And in formulating his famous uncertainty principle, Werner Heisenberg showed it was impossible to determine both the exact position and speed of electrons as they moved around an atom. The idea that electrons cannot be pinpointed but exist within a range of possible locations gave rise to the current quantum model of the atom, a fascinating theory with a whole new set of complexities whose implications have yet to be fully grasped. Even though our understanding of atoms keeps changing, the basic fact of atoms remains, so let's celebrate the triumph of atomic theory with some fireworks. As electrons circling an atom shift between energy levels, they absorb or release energy in the form of specific wavelengths of light, resulting in all the marvelous colors we see. And we can imagine Democritus watching from somewhere, satisfied that over two millennia later, he turned out to have been right all along.

LESSON 2 Early Theories on the Origin of Life • Identify the different theories on the origin of life. • Describe each theory and determine their differences What are the characteristics of living things? Before learning about the history of Earth based on geological evidence, early scientists explored the possibilities of how the first life-form existed. There are several theories about the origin of life. Theory of Catastrophism The theory of catastrophism supported by French scientists Georges Cuvier (1769-1832) and Alcide Dessalines d'Orbigny (1802-1857), is said to be a modification of the creation story of the Bible. It states that there have been several living creations from God, each encountered a catastrophe that completely destroyed them. Each new creation consisted of new life-forms, which happen to be different from the previous ones. Theory of Abiogenesis The theory of abiogenesis, or the spontaneous generation theory, states that living things were naturally created from nonliving things such as simple organic compounds. The theory supposes that abiogenesis occurred between 3.8 and 4 Gya. The experiment performed by Stanley Miller in 1953 gave way to many speculations and studies on how life on Earth really began. His research involved a simulation of the possible environment on Earth in the past. He demonstrated how an electric spark (which is a simulation for lightning) when passed through simple organic gases (similar to the early Earth atmosphere), resulted in the formation of amino acids, which are now known as the building blocks of proteins and the components of living tissues. Theory of Biogenesis The theory of biogenesis presented a strong argument against abiogenesis. This theory states that living things come from living things. Experiments of Francesco Redi and Louis Pasteur disproved the thought of spontaneous generation during their time (figure 5-1). Louis Pasteur argued that life comes from preexisting life and not from nonliving material. However, it should be noted that the "abiogenesis" or "spontaneous generation" that he opposed referred to any modern, existing, fully-formed organisms, not the original generation of life. Louis Pasteur's law of biogenesis contradicted the common belief during his time that cattle dung gives rise to flies, or old clothes with rotten food gives rise to mice. The idea of spontaneous generation was popular until near the seventeenth century. Even famous scientists of that period, such as Descartes, Galileo, and Jan Baptista van Helmont, believed in this theory. CIENCE PIONEER Francesco Redi (1626-1697). Francesco Redi is a physician, a naturalist, and a poet. His works challenged the popular theory of spontaneous generation. He disproved the idea that living things may arise from nonliving things. He also worked on toxicology using viper's venom. He discovered and worked on some parasites that caused disease in humans. SCIENCE CAREER Evolutionary Biologist An evolutionary biologist studies the descent of species and the origin of new species of living things. Working as evolutionary biologist means studying and researching species diversity, their interaction with the environment, their adaptation to change, their ancestors, and their possible origins. This career is important in the field of science because it seeks an answer to the questions about how life began on Earth.

Some Arctic Dinos Lived in Herds By Sid Perkins Just as interesting, however, is how this was discovered. Scientists didn’t look at a single fossil bone. Instead, they analyzed a large number of preserved footprints on a mountainside located toward the southern end of central Alaska. Anthony Fiorillo works at the Perot Museum of Nature and Science in Dallas, Texas. As a vertebrate paleontologist, he studies the fossils of creatures with backbones. In 2007, he was part of a research team exploring Denali National Park. “We rounded the corner and there they were,” he recalls. Thousands of footprints had been preserved in stone. “It was amazing.” Dinosaurs died out more than 65 million years ago (not counting birds, their modern-day relatives). So, it’s a bit surprising that scientists know so much about these ancient creatures. Now, a new study reveals that a certain type of duckbilled dinosaur lived in the Arctic year-round. These animals also traveled in herds that included many age groups, they find. The creatures even appear to have gone through a “teenage growth spurt.” Those tracks pepper a steep patch of exposed rock about twice as long as a football field and up to 60 meters (roughly 200 feet) wide. They sit at least 160 kilometers (100 miles) north of the Gulf of Alaska. Between 69 million and 72 million years ago, that now-rocky material was muddy sediment on a floodplain near a seacoast, Fiorillo explains. The hadrosaurs walked across the squishy mud. Later, the footprints they left turned to stone. Previous studies suggested adult duckbills took care of their young, says Fiorillo. The new evidence that these dinosaurs truly traveled in herds with multiple age groups confirms that parents cared for their young well beyond the time they left the nest, his team concludes. The researchers published their findings June 30 in Geology. © Science News for Students Thousands of tracks cover this rocky mountainside in Alaska’s Denali National Park. They provide a wealth of information about the size, age and lifestyle of certain dinosaurs. COURTESY OF PEROT MUSEUM OF NATURE AND SCIENCE EVIDENCE FOR HERDS O F DINOSAURS Small meat-eating dinosaurs called theropods had left behind a few of the tracks that Fiorillo’s team found in Denali. Birds had left some others. But the vast majority came from creatures called hadrosaurs. These large plant-eating duckbilled dinosaurs had been quite common during the Cretaceous Period. That helps explain one of their nicknames: “cattle of the Cretaceous.” For the new study, the researchers focused only on the hadrosaur tracks. More than half of the footprints were preserved so well that they had clear impressions of the skin on the dinosaurs’ feet. Most tracks had a similar level of preservation. That suggests all were probably left within a short period. Other fossils in the nearby rocks, including insect burrows, suggest these hadrosaurs had left their footprints during the summer. These are trace fossils — evidence of ancient life other than a preserved carcass or bone. At the time these dinosaurs lived, Fiorillio says, the average temperature in the warmest months was between 10° and 12° Celsius (50° and 54° Fahrenheit). That’s about what conditions are like today along the border between Canada and the lower 48 U.S. states, he notes. The team measured a large sample of the duckbills’ footprints. They fell into four distinct size ranges. The largest tracks, presumably made by adults, measured about 64 centimeters (25 inches) across. The smallest tracks, 8 centimeters (3 inches) wide, were likely left by young duckbills. They would have been no more than a year old. Tracks of two other size groups were probably made by juveniles and near-adults. These data suggest the community of hadrosaurs included four different age groups. © Science News for Students A hadrosaur footprint made roughly 70 million years ago. For scale, the long blue bar at right is 10 centimeters long; each small blue or white bar measures 1 centimeter. COURTESY OF PEROT MUSEUM OF NATURE AND SCIENCE © Science News for Students THESE DINOSAURS DIDN’T MIGRATE About 84 percent of the tracks sampled for the new study had been left by older hadrosaurs — adults or near-adults. Roughly 13 percent came from the youngest members of the herd. And a mere 3 percent came from herd members considered to be juveniles, says Fiorillo. The rarity of tracks by these tweens suggests that the young of this species had a rapid growth spurt. If true, they would have spent relatively little time at this vulnerable size — and therefore left very few tracks. “What’s really neat is how many small tracks there are,” notes Anthony Martin. An ichnologist — or expert in trace fossils — he works at Emory University in Atlanta, Ga. Other scientists had analyzed fossil bones from duckbills. These studies had hinted that the equivalent of adolescent hadrosaurs would have experienced growth spurts. But the new findings are “the best evidence that I’ve seen,” says Eric Snively. He’s a vertebrate paleontologist at the University of Wisconsin- La Crosse. “This is a great study,” he adds, “and further evidence that juvenile hadrosaurs grew up in an eye-blink.” Also previously, researchers had proposed that Arctic dinosaurs migrated farther south for the winter. That’s because even if the region was much warmer than it is today, nights in the high Arctic would have been 24 hours long. So, with no sunshine for several months, Alaska would have had long periods of very bleak, chilly weather. But finding juveniles in the herd strongly suggests that these dinosaurs remained in the Arctic all year. That’s because adolescents and preadolescents wouldn’t have had the strength or stamina to make those long treks, Fiorillo maintains. Field work is often harsh. Paleontologists studying the dinosaur footprints here on an Alaskan mountainside sometimes worked in cold and fog. COURTESY OF PEROT MUSEUM OF NATURE AND SCIENCE © Science News for Students The presence of very young dinosaurs might have been expected, he notes: If this were a nesting region, the babies would have hatched sometime just before summer. And remember, that’s when these tracks were left. But that wouldn’t explain the juveniles, he says. The team’s findings “suggest that these dinosaurs were overwintering in Alaska somehow,” says Snively. At the time, the average temperature in the region remained above freezing even during the winter, he notes. But, he adds, “this study raises interesting issues about how the dinosaurs could live in the region when it was pretty dark for several months at a time.”

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