Fourth Grade: Unit 4 Matter: Physical Changes. matter property physical change

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1 Fourth Grade: Unit 4 Matter: Physical Changes matter property physical change Background Information for the Teacher: The universe is made of only two entities: matter and energy. Examples of energy are light, heat, and sound. Everything else we know of is matter. Matter is anything that has mass and volume. Mass is the amount of atomic material an object is composed of. Usually, when an object is heavier, it has greater mass. Compare the mass of a styrofoam ball to the mass of a bowling ball. The bowling ball has greater mass because it has more matter within it. The styrofoam ball has less mass because it is made of less matter, making it feel lighter. Mass does not change the way weight does. Weight is a measure of the gravitational pull on an object. It will change depending on the distance from the object to the center of the Earth. An object put on a scale at sea level will weigh more than the same object put on a scale in mile high Denver. Because Denver is over 5000 ft. above sea level, the gravitational pull is less, making the weight of the object less. The mass of the object will remain the same wherever the object is located. Mass measures the amount of atomic material in the object, not the gravitational pull on the object. Volume is the amount of space than an object can occupy. An inflated balloon may have a volume similar to a bowling ball, because they both take up about the same amount of space, but it will have a much different mass. All matter has volume, though young students have difficulty with the idea that something invisible, like air, can take up space. Matter is found in three natural states on Earth. These are solids, liquids, and gases. Water as a solid is found as ice, as a liquid in fluid water, and as a gas in water vapor in the air. A fourth state of matter, plasma, is the most common in the Universe but is only found in stars and between planets, stars, and galaxies. It does not need to be presented at this level. Elements like oxygen, carbon, nitrogen, iron, gold, silver, magnesium and lead are sometimes found in pure form, but most matter is a combination of different elements. Water is matter; it has mass and takes up space, and it is a combination of the two elements hydrogen and oxygen. Salt, another common Earth substance, is formed from the elements sodium and chlorine.

2 Atoms are the basic units of matter. They are made of positively charged protons, neutrally charged neutrons, which are both located in the nucleus, and negatively charged electrons, which circle the nucleus in an electron cloud. A property of matter is its characteristics. There are physical and chemical properties of every kind of matter. Children at this level can easily explore the physical properties of matter by using their five senses. A physical property of matter is any property you can see, smell, touch, hear or otherwise detect and measure without performing a chemical reaction. (such as burning) These include such characteristics as color, shape, size, volume, mass, density, texture, flexibility, and buoyancy. We sort types of matter into categories depending on characteristics, or properties. Changes in physical properties are called physical changes. Water as a gas to a liquid to a solid looks and behaves differently, but the atomic structure and organization remain the same, thus the changes in state are physical changes. Physical changes are typically simple to reverse. Wadding up a piece of paper may change its appearance, but the molecular structure is unchanged. Rearranging the color, shape, or size of an object without changing its chemical makeup are all examples of physical changes. Physical changes may change the appearance of an object or substance, but do not change the molecular make up. Matter: any substance that has mass and volume Property: a characteristic, attribute that describes a condition of matter Physical Change: a change involving the physical properties (characteristics) of matter

3 Activity 1: Show the students the cover of Agatha s Feather Bed. Ask them to describe the objects they see in the illustration. Prompting questions might be: Who is Agatha? Where does the story take place? What time of day is it? How do you know? What are the cats doing? How many cats are there? Where is everyone looking? What are they looking at? Read the story up to page 15 only. Stop at the sentence: She turned slowly in bed and saw that standing across her windowsill were

4 Ask students to complete the rest of the story. What were standing on Agatha s windowsill? Why? Encourage students to develop the next events of the story, prompting them with sequence and possible events if necessary. Ask students to describe new characters and situations to enrich the reader experience. Allow them to be as creative as possible during this free writing period. Once the story is completed, read it to the students in entirety. After modeling fluency, have them read the text orally and silently. This will help them develop fluency. If the students wish to delete or add material for clarification, make changes necessary.

5 Activity 2: Ask students to look at the picture below. As they observe the picture, have students describe the object in as much detail as possible. Even though this is just a visual of the object, encourage students to use all five senses: sight, sound, smell, taste, and touch. Challenge them to use as many adjectives as they can to enrich their description. Record their responses on a chart like the one below. Ingredients What I See What I Smell What I Feel What I Hear What I Taste After they have completed the chart, tell the students: Imagine you have this whole cookie loaded with chocolate chips, nuts, and caramel chunks. It is so loaded and so big it weighs 10 pounds! Yum! Yum! But you drop the cookie and it breaks into a thousand pieces on the floor. Oh no! You pick up all of the crumbs and pieces of cookie and put them on a scale. How do you think the weight of all the crumbs and pieces of cookie will compare to the pound of cookie when it was whole? Choose what you think is the correct statement below. A. The whole cookie weighs more than all of the crumbs and pieces of broken cookie.

6 B. The cookie crumbs and pieces weigh more than the whole cookie. C. The whole cookie weighs 10 pounds and all of the crumbs and pieces of broken cookie weigh 10 pounds. Once the students have chosen a statement, encourage them to explain why they chose that response. Record their responses and explanations. When all students have contributed, have the whole group decide on which response they think offers the best explanation. If the group cannot decide on one response, allow them to choose the top two or three. Mark these choices. Tell students that when they described the cookie in Activity 1 they were using physical properties to describe matter. Matter is anything that has mass and takes up space. A physical property is anything that describes an object using the five senses, and all objects are matter. Characteristics like state or phase, shape, size, weight or mass, volume, color, texture, luster, and flexibility are all physical properties. The changes in the cookie from whole to broken are changes in some of the physical properties of the cookie. Breaking it changed it in size, shape, and texture, but did not change it chemically into a new substance. Because the cookie retains all its other physical properties, and therefore is still a cookie, its mass or weight will not change. The whole cookie weighed 10 pounds, so the parts of the cookie, the crumbs and broken pieces, will also weigh 10 pounds. No matter is lost when an object changes in physical characteristics. The correct statement is C.

7 Activity 3: Student Handout 1 Most matter goes through physical changes easily. Water freezes as ice, melts into water and evaporates into vapor on a constant cycle. Agatha discusses how everything comes from something, and usually these involve physical changes of matter. Tell students they are going to research a particular mix of matter called a Snickers bar. Ask the students to read each statement below about Snickers candy bars. Have them decide if they think the statement is true or false. True statements are marked as YES and false statements are marked as NO. Encourage students to explain why they think the statement is true or false and what changes could be made to make the statement true. Statement Yes No My Thoughts Snickers candy bars were named after a type of laugh. Snickers factory uses over 99 tons of peanuts every day. There are egg whites and peanut butter in Snickers. Snickers were invented more than one hundred (100) years ago. Snickers are made in Chicago, Illinois. There are about 50 peanuts in every regular size Snickers bar. Each Snickers bar has a distinctive squiggle put on the chocolate coating. Snickers are the best selling candy bar in the world. Once the students have completed their charts, discuss each statement to see if there is class consensus. Record students explanations. Explain to students that they will find the answers to the statements in the following video. Ask students to pay attention to the physical changes the ingredients of a Snickers bar go through as they move from raw materials to the final product.

8 Activity 4: Student Handout 2 Review up to page 15 of Agatha s Feather Bed. Show students the list of items below. Source Product Description of Change Sand in oyster Pearl Sap of rubber tree Rubber balls Cotton plant Denim jeans Milk Ice cream Worm cocoon Silk Cow hide Leather boots Flowers perfume Turtle shells Head bands Discuss the type of change each source must go through to create the end product. Are they changes in size, shape, texture, or color? Does the actual source item become something chemically different? Encourage students to discuss the physical changes that might occur to make the finished products. The descriptions do not have to be scientifically accurate. It is more important that students realize there are a wide variety of physical changes that matter can go through. Review the end of the story the students developed in Activity 1. Do any physical changes occur to objects or living things in the story? Have students describe any changes they created.

9 Activity 5: Student Handout 3 Read the remainder of Agatha s Feather Bed. Discuss how Agatha solved the problem with the geese and what changes occurred in solving the problem. Have students use the story and its ideas to complete the diagram. Draw two examples of a physical change here. Describe the difference between physical properties and physical changes here. Physical Changes Write four facts about physical change here. Write a definition of physical changes here.

10 Student Handout 1 What I See What I Think

11 Word Matter Student Handout 2 Knowledge Rating Scale Know it Well Give a Definition/Examples Have Seen It/Heard It Tell What You Know No clue Take a Guess Physical Properties Physical Changes

12 Student Handout 3 Draw an example. Decribe difference. Physical Changes Write four facts. Write a definition.