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Fifth Grade - Science - Overview - October

The seven lessons in this month's unit deal with 'Physical Change: Energy Transfer.' As such, they are a development of September's unit 'Matter and Change.' The material offers many interesting opportunities for demonstration of the topics discussed. These opportunities should be utilized so as to involve students in the concrete world of chemistry. Lesson 1 describes physical change as a change of phase. Lesson 2 looks at the processes by which phases change: condensation, freezing, melting, boiling. Lesson 3 teaches that different amounts of energy are needed for physical change. Lesson 4 studies the three ways heat can be transferred: conduction, convection, and radiation. Lesson 5 describes expansion and contraction. Lesson 6 deals with the special case of water, which expands when changed from a liquid to a solid. Lesson 7 is about the separation of substances with different boiling points, or distillation.

Fifth Grade - Science - Lesson 7 - Energy

Objectives
Review the properties of different phases of matter.
Understand the role of molecular attraction in phases of matter.
Understand that matter can be made to change phases by adding or removing energy.

Materials
Drawing of solid, liquid, and gas molecules, attached (for transparency)

Suggested Books
Teacher Reference
Berger, Melvin. Solids, Liquids, and Gases: From Superconductors to the Ozone Layer. New York: G. P. Putnam's Sons, 1989.
Hirsch, E. D. What Your 5th Grader Needs To Know. New York: Doubleday, 1993.

Teacher Background

In fifth Grade Science, Lesson 1 dealt with 'Matter,' Lesson 2 dealt with 'Atoms,' Lesson 5 dealt with 'Molecules,' and Lesson 6 dealt with 'Physical and Chemical Change.' In Fourth Grade Science, 'The Properties of Matter,' was introduced. In Science in First Grade, 'The Three Phases of Matter,' and 'The Changing Phases of Water,' were presented. 'Phases of Matter' is presented in Reading Mastery 1V, Lessons 104, 105, and 106. 'Expansion,' is covered in Reading Mastery 1V, Lessons 10 and 110, and in Reading Mastery 111, Lessons 49, 50, and 65. 'Changing Phases,' is discussed in Reading Mastery 1V, in Lesson 109. 'Phases of Matter,' is presented in the Academic Core, Level 111. Therefore, only a quick review of the properties of phases of matter is necessary here. This lesson focuses on molecular attraction and changing phases by adding or removing energy to a substance.

Matter exists in three phases: solids, liquids, and gases. Each phase has specific properties. Solids hold a definite shape and are firm to the touch. Liquids take up the shape of the container in which they are placed, are wet to the touch, flow, and have a definite volume. Gases expand and fill up space. Gases and liquids do not have a shape of their own. The concept of phase really refers to the arrangement of molecules in matter. Molecules attract each other. Molecules also move rapidly. In the solid state, the attraction is strongest, and molecules are closely packed. This explains why solids are firm and keep their shape. The molecules in liquids attract each other less strongly and are less closely packed than is the case with solids. The molecules in gases are the least attracted to each other and the least closely packed of all the phases. A change of phase is thus a change to the attraction of one molecule to the other. In a phase change, molecules of a substance become either less attracted to each other or more attracted to each other. The result is that molecules are either less or more closely packed together, which explains why matter in various phases is more or less rigid or firm. Matter is made to change phase when energy is added or removed beyond certain points.

Procedure
Start by reminding students that in Science, Lesson 1, during the month of September, they studied matter. Ask: What are the three phases of matter? (solids, liquids, gases) Ask forexamples of solids (answers may vary), liquids, (answers may vary) and gases (answers may vary). Ask: Do solids have a definite shape? (yes) Ask whether liquids have a definite shape (no).

Ask: Does water vapor have a definite shape? (no). Ask: What is all matter made up of? (molecules) Tell students that you are about to discuss the behavior of molecules in different phases of matter. Tell students that they might look at this part of the lesson like a soap opera. Explain that it is not such a far-fetched idea anyway, since characters in soap operas are sometimes described as hot or cold, and that attraction between characters is called chemistry. Explain that this part of the lesson is about molecules attracting each other and fighting efforts to break them apart.

Next, put up the transparency of molecules in different phases. Ask students to observe that the diagram depicts a melting block of ice to which more and more heat energy is added. Explain that the thermometer in the diagram symbolizes that more heat energy is added as we go to the right of the diagram. To check whether students understand the diagram, ask: To which block of ice has most heat energy been added? (smallest, farthest right) Ask students to read the labels on the transparency. Ask them to observe the spaces between molecules in each phase of water, and to compare the distances between molecules in each phase (Molecules are farther apart as we move from the solid phase to the gas). Point to the signs of movement (rings around the molecules) that are especially pronounced around the molecules of the liquid phase and even more so in the gas phase. Ask students to explain why as we move from solid to liquid to gas, molecules grow farther and farther apart. Ask students to explain why there are markings showing movement in the liquid and gas phases and that the markings are more pronounced in the gas phase. Explain that as heat energy is added to the solid ice in the diagram, it weakens the forces of attraction between the molecules up to the point where the molecules vibrate more rapidly and the solid ice melts to the liquid water. Explain that as heat energy is added to the liquid phase, the molecules vibrate even more rapidly and the liquid turns to steam. Explain, however that the molecules counteract this effort to break them apart by attracting each other, and that heat energy fights and weakens that attraction.

Finally, ask students to work individually or in groups to state a law that explains the relationship between heat energy, molecular attraction, and the vibration of molecules. Tell students that the law should look like this: The ....... the heat energy added to a substance, the ......... the molecular attraction between molecules of that substance, and the....... the vibration of molecules of that substance. Explain that they must use one of the two words, 'greater,' or 'less' in each of the spaces provided. Reverse the order of this law by switching the use of the words, 'greater' or 'less' provided in a sentence that reads like this: The ....... the heat energy subtracted from a substance, the ......... the molecular attraction between molecules of that substance, and the....... the vibration of molecules of that substance. Tell students that reading the diagram from right to left supports that law. Conclude by telling students that this means adding or removing heat energy can result in a change of phase. Finally, ask students the following: What is the coldest phase? (solid) What is the next hottest phase? (liquid) What is the hottest phase? (gas)
 

Fifth Grade - Science - Lesson 8 - Melting, Freezing, Boiling, and Condensation
 

Objectives
Describe the processes of freezing, melting, boiling, and condensation.
Recall that a change of phase is a physical change.

Suggested Books
Teacher Reference
Berger, Melvin. Solids, Liquids, and Gases: From Superconductors to the Ozone Layer. New York: G. P. Putnam's Sons, 1989.
Hirsch, E. D. What Your 5th Grader Needs To Know. New York: Doubleday, 1993.

Teacher Background

In Fifth Grade Science, Lesson 1 dealt with 'Matter,' Lesson 2 dealt with 'Atoms,' Lesson 5 dealt with 'Molecules,' and Lesson 6 dealt with 'Physical and Chemical Change.' In Fourth Grade Science 'The Properties of Matter' was introduced. In Science in First Grade 'The Three Phases of Matter,' and 'The Changing Phases of Water,' were presented. 'Phases of Matter' is presented in Reading Mastery 1V, Lessons 104, 105, and 106. 'Expansion,' is covered in Reading Mastery 1V, Lessons 10 and 110, and in Reading Mastery 111, Lessons 49, 50, and 65. 'Changing Phases,' is discussed in Reading Mastery 1V, in Lesson 109. 'Phases of Matter,' is presented in the Academic Core, Level 111. Therefore, only a quick review of the properties of phases of matter is necessary here. This lesson focuses on condensation, freezing, melting and boiling. Remove heat energy from a substance and it cools. Adding energy to a substance warms it. The solid state is the coldest state of matter. The solid state of water is ice. Warm ice to 0C and it melts, or turns to liquid. Cool liquid water to 0C and it freezes. OC is thus both the freezing and melting temperature or point of water. Heating liquid water to a temperature of 100C will cause it to boil or change to a gas, the hottest state of matter. 100C is thus the boiling temperature of water. 100C is also the temperature at which water vapor condenses or turns to liquid water.

Procedure
Tell students that this lesson deals with the four ways in which substances change phases or states. Explain that water is the substance used in all examples. Recall that in previous Fifth Grade lessons, students learned about phases or states. Ask: In how many states or phases can water exist? (three) Ask: What are these states or phases? (liquid, gas, solid) Ask: What are these phases of water called? (ice, water, steam) Ask: What are the properties of solids? (have shape and volume of their own) Ask: What are the properties of liquids? (they take up shape of the container they are in, have no shape of their own) Ask: What are the properties of gases? (have no volume or shape of their own) Ask students to arrange these phases from the coldest to the hottest (solid, liquid, gas). Tell students that changing the phases or states of water or any substance is only a physical change or a change of appearance. Ask: What other type of change is possible? (chemical change) Ask: What is the difference between a physical and a chemical change? (in physical change, no new substance is created, only the hardness or other physical appearance is altered, whereas in chemical change, a whole new substance is created) Remind students that this lesson deals only with physical change. Tell students that changing states is caused by heating or cooling. Ask: How does one heat or cool a substance? (by adding or removing heat energy) Tell students to think of a block of solid ice. Explain that this is the form of water at its coldest and this is always at a temperature below 0C. Explain that adding heat energy, by placing the ice block in a pan over the fire for example will result in warming. Explain that the ice block will not change its appearance, that is, it will remain solid until it warms to a temperature of 0C. At that point, the ice block will begin to melt or turn to liquid. Explain that this makes 0C the melting temperature of water. Explain that since we speak of melting in relation to solids, it means that if heat energy is added to solid water, it will melt. Ask students to think of liquid water. Ask: Above what temperature does liquid water exist if the melting temperature of solid water or ice is 0C? (above 0C) Ask: What will bring liquid water to 0C, heating or cooling? (cooling) Ask: What will happen to liquid water if it is cooled to 0C? (freeze) Explain that freezing or turning from liquid to solid is a phase change. Emphasize that 0C is also the freezing temperature of liquid water. Ask: Are the freezing and melting temperature of water the same temperature? (yes) Ask: Are freezing and melting the same idea? (no) Explain that both freezing and melting take place at the same temperature for each substance but that freezing and melting are two different things. Ask: What two things do freezing and melting have in common? (both are phase changes, both take place at the same temperature in the same substance, 0C in the case of water) Ask: In what way is freezing different from melting? (melting is change from solid to liquid, freezing is change from liquid to solid) Explain that melting and freezing temperatures are also referred to as the melting point and freezing point. Illustrate by explaining that to say, '0C is the melting temperature of water,' is the same as saying, '0C is the melting point of water.'

Explain that just as liquid may be frozen or turned to a solid, a liquid may be brought to a boil. Ask: What is boiling? (change from liquid to a gas) Ask: How do you boil water, by adding or removing heat energy? (adding heat energy) Ask: What is it important to know if you intend to boil a substance, water for example? Remind them that they just learned the same thing in relation to freezing and melting. (boiling temperature or point of substance, water for example) Ask: What is the boiling point of water? (100C) Ask: What happens to liquid water at 100C? (water boils or changes to gas) Ask: Is boiling a change of phase or state? (yes) Ask: Is boiling a physical or chemical change? (physical) Ask: Why is boiling physical and not chemical? (change of appearance only) Explain that steam or water in the gaseous phase can be cooled till it turns to a liquid and that the change of phase from a gas to a liquid is called condensation. Ask: Is condensation a physical or chemical change? (physical) Explain that all substances undergo phase changes at particular temperatures.

Review the main points of this lesson by asking the following questions.
1. What are the three states of matter? (solids, liquids, gases)
2. Arrange the phases from coldest to hottest (solids, liquids, gases).
3. Name a phase change that solids undergo (melting).
4. Is melting caused by heating or cooling? (heating)
5. What is melting? (change from solid to liquid)
6. Name two phase changes that a liquid undergoes (freezing, boiling).
7. What is freezing? (change from liquid to solid)
8. Is freezing caused by heating or cooling? (cooling)
9. What name is given to the temperature at which a liquid turns to a solid? (freezing temperature or point)
10. Name another phase change that a liquid undergoes? (boiling)
11. What is boiling? (change from liquid to gas)
12. Is boiling achieved by heating or cooling? (heating)
13. What name is given to the temperature at which a liquid turns to a gas? (boiling temperature or point)
14. Name a phase change that a gas undergoes (condensation).
15. What is condensation? (change from gas to liquid)
16. How is condensation achieved, by heating or cooling? (cooling)
17. What does a phase change do to the molecules of a substance? (rearrange them so that they vibrate more or less, more as the substances passes from cooler to warmer phases, less from hotter to cooler phases)

Fifth Grade - Science - Lesson 9 - Each substance has its own Boiling Point

Objectives
Understand that it takes different amounts of energy to change phases of different substances.
Understand that each substance has its own melting and boiling points.

Materials
Diagram of phase changes in water and copper

Suggested Books
Teacher Reference
Berger, Melvin. Solids, Liquids, and Gases: From Superconductors to the Ozone Layer. New York: G. P. Putnam's Sons, 1989.
Hirsch, E. D. What Your 5th Grader Needs To Know. New York: Doubleday, 1993.

Teacher Background
In Fifth Grade Science, Lesson 1 dealt with 'Matter,' Lesson 2 dealt with 'Atoms,' Lesson 5 dealt with 'Molecules,' and Lesson 6 dealt with 'Physical and Chemical Change.' In Fourth Grade Science 'The Properties of Matter' was introduced. In Science in First Grade 'The Three Phases of Matter,' and 'The Changing Phases of Water,' were presented. 'Phases of Matter' is presented in Reading Mastery 1V, Lessons 104, 105, and 106. 'Expansion,' is covered in Reading Mastery 1V, Lessons 10 and 110, and in Reading Mastery 111, Lessons 49, 50, and 65. 'Changing Phases,' is discussed in Reading Mastery 1V, in Lesson 109. 'Phases of Matter,' is presented in the Academic Core, Level 111. This lesson focuses on the principle that every substance has its own boiling and freezing points and consequently different amounts of energy are needed to change phases of different substances. Water freezes at 0C or 32F and boils at 100C or 212F.

Procedure
Start by recalling that in Lesson 7, students learned how heat energy affected matter. Ask: What happens to a substance's molecules when heat energy is added to it? (It weakens the attraction between molecules of the substance, forces them farther apart, and causes them to move more rapidly.) Ask: What is the hottest phase or state of matter? (gas) Ask: In what phase or state of matter are a substance's molecules most energized? (gas) Emphasize that adding or removing heat energy from a substance can cause a phase change. Students studied phase changes in Lesson 8. Ask them to recall at what temperature liquid water freezes (0C). Ask: At what temperature does liquid water boil? (100C) Tell students that they are about to compare the phase changes of melting and boiling in water and copper. Ask: What is boiling? (change from liquid to gas) Ask: What is melting? (change from solid to liquid) Recall that copper was studied recently in Chemistry. Ask those students who might have a copy of the Periodic Table attached to their notes to consult them and to locate copper on the Periodic Table. To guide the search for copper on the Periodic Table, ask: What is the symbol of copper? (Cu) Direct students to locate copper on the Periodic Table and to observe that it is located to the left of the step-ladder on the Periodic Table. Ask: What type of substance is copper? (metal) Ask: What are the characteristics of metals? (dense, shiny) Ask: Which of these two characteristics of copper will affect the temperature at which it melts or boils? (dense) Ask: What is water in the solid state? (ice) Ask: What are the characteristics of ice? (Answers will vary but should include density.)

Remind students that pennies are made of copper and ask students to compare the density of the metal copper and the non-metal ice (copper is more dense).

In Fourth Grade students learned that density was the amount of matter that was packed in the space a substance occupied so that the higher the density, the higher the amount of material that was packed into the space that the substance occupied. Ask: Who can explain the density of substances? Guide students along by explaining that they must use the concept of the attraction of molecules learned in Lesson 7 to explain it. Emphasize that although both ice and the copper penny are in the solid state and that in this the coldest state of matter the molecules are packed the closest together, the molecules of copper are packed much more closely in copper than in ice, hence the observation that solid copper is more dense than ice. Tell students to bear in mind that melting is really heat energy breaking the attraction of a solid's molecules and ask whether it will take the same amount of heat energy to melt solid ice and solid copper (no). Ask: Which will have the lower melting temperature? (ice) Ask: What is the melting temperature or point of water? (0C). Ask: What is the melting temperature of solid copper? Tell them to bear in mind that the melting point is the temperature at which a copper penny will melt. Ask them to guess what it might be, then inform students in writing and orally that it is nearly 1,083C. Ask: What is the melting temperature of copper? (1,083C) Ask: What is the boiling temperature of water? (100C) Ask: What is the boiling temperature of copper? Guide students by asking whether the boiling temperature will be higher or lower than the melting temperature (higher). Ask students to guess the answer, then present orally and in writing the temperature of 2,300C. Conclude by telling students that every substance has its own boiling and melting point and that it means that each substance requires a specific amount of energy to cause it to change from a liquid to a solid, from a liquid to a gas, or for any phase change.

Activity
Ask students to do the following.
1. Make two sets of diagrams, one for water, one for copper, each containing three pictures of the solid, liquid, and gas phase of each substance and indicating the temperature at which each substance undergoes a change of phase.
Note to the Teacher: A diagram of this activity has is included for your consideration.

Fifth Grade - Science - Lesson 10 - Three Means of Heat Transfer

Objectives
Understand convection as a means of heat transfer.
Understand conduction as a means of heat transfer.
Understand radiation as a means of heat transfer.
Understand insulation as a process of hindering heat transfer.

Materials
Drawing of convection and conduction, attached (for transparency)

Suggested Books
Teacher Reference
Berger, Melvin. Solids, Liquids, and Gases: From Superconductors to the Ozone Layer. New York: G. P. Putnam's Sons, 1989.
Hirsch, E. D. What Your 5th Grader Needs To Know. New York: Doubleday, 1993.
Division of Curriculum Development Office of Science and Health, BCPS. STARS Elementary
Science Curriculum. Baltimore: Baltimore City Public Schools, 1991.

Teacher Background
In Fifth Grade Science, Lesson 1 dealt with 'Matter,' Lesson 2 dealt with 'Atoms,' Lesson 5 dealt with 'Molecules,' and Lesson 6 dealt with 'Physical and Chemical Change.' In Fourth Grade Science, 'The Properties of Matter,' was introduced. In Science in First Grade, 'The Three Phases of Matter,' and 'The Changing Phases of Water,' were presented. 'Phases of Matter' is presented in Reading Mastery 1V, Lessons 104, 105, and 106. 'Expansion,' is covered in Reading Mastery 1V, Lessons 10 and 110, and in Reading Mastery 111, Lessons 49, 50, and 65. 'Changing Phases,' is discussed in Reading Mastery 1V, in Lesson 109. 'Phases of Matter,' is presented in the Academic Core, Level 111. The concepts conduction and insulation were introduced in Fourth Grade Science. This lesson focuses on the concept of transfer of heat. Conduction is the transfer of heat energy in which moving particles make other particles move. Some materials are better conductors than others. Metals, for example, conduct heat much better than do plastics or wood. Convection is the transfer of heat energy that results from cool liquid sinking and taking the place of the warm liquid that is below it. This occurs because a cold liquid is heavier than the warm one. Heat is transferred by convection. Radiation is the transfer of heat energy by means of waves that can go through empty space. Waves of light from the sun are one such example. Heat transfer may be reduced. This is called insulation. Some substances are better insulators than others.

Procedure
Tell students that they are going to get an explanation for something they might already have observed at home; how heat energy flows. Point to the top diagram. Explain that this diagram shows the flow of heat within a liquid. Explain that heat flows from warmer molecules to cooler ones. Point to the liquid water. Ask: Is the water equally warm throughout the pan? (no) Ask: Which part is warmer, nearer the base or nearer the surface? (nearer the base) Explain that the part of water that is closer to the surface is cooler. Explain that the cooler part of the water is more dense and heavier than the warmer part nearer the base. Ask: Why is warmer water less dense than cooler water? (more energized molecules are farther apart than are cooler ones) The same way a pebble would sink to the base of the pan, the cooler heavier water sinks to the base. Explain that this displaces the lighter warmer water towards the surface. Tell students that soon this part of the water which was once closer to the surface and is now closer to the base gets warmer and lighter and is in turn displaced upwards. Emphasize that this process is called convection.

Point to the coffee mug in the second diagram. Ask: What items are portrayed in that diagram? (mug, coffee, spoon, steam) Point out each of these objects on the diagram. Ask: Can you match each item with the phase or state in which it exists? (mug, solid; spoon, solid; coffee, liquid; steam, gas) Ask: Are all the items in the diagram equally warm? (no) Ask: Which is warmest? (coffee) Emphasize that heat flows from warmer molecules to cooler ones. Point to the spoon. Explain that part of the spoon is above and part is below the surface of the hot coffee. Ask: Are both parts of the spoon, that part that is below the surface of the coffee and that part that is above registering the same temperature? (no) Ask: Which part is warmer? (below the surface) Recall that students have learned the behavior of molecules in different states or phases, especially how much they vibrate in relation to the presence of heat energy. Point to the section of the drawing showing behavior of molecules in both parts of the spoon. Recall that this was studied in Chemistry Lesson 7, 'Energy.' Ask for volunteers to explain the behavior of those molecules. Emphasize that molecules in the warmer part of the spoon, that part below the surface of the hot coffee, are farther apart, and vibrate more rapidly than those above the surface. Explain further that heat energy travels up the spoon's handle by the process of conduction. Explain conduction as follows: that part of the spoon below the surface is so warm that its molecules vibrate rapidly. These molecules are connected to surrounding molecules and so forth all the way to the handle. The vibration of those molecules below the surface set those above the surface vibrating, too. Ask: What would happen if you touched the handle of the spoon? (sensation of heat) Explain that this heat sensation is the result of the molecules of your fingertips vibrating from contact with the vibrating molecules of the spoon. Emphasize that conduction is the flow of heat whereby moving particles make other particles vibrate. Emphasize that this process is occurring within the coffee and the spoon and throughout the spoon. Ask: From your experience and observations at home, which type of spoon would become warmer if placed in the same cup of coffee, a metal spoon, or wooden spoon? (metal) Explain that this because metals conduct or allow the transfer of heat much better than do wood or plastic.

Tell students that the third form of heat transfer is very important for life on earth. Explain that the sun sends out waves of light and that on the way from the sun to the earth, these waves of light travel through empty space to reach the earth. When these waves hit matter they warm matter up. Explain that radiation is the transfer of heat by way of waves that can go through empty space.

Finally, tell students that heat energy does not flow through all materials at the same rate, and that some substances called insulators prevent the rapid transfer of heat. Recall that students were introduced to the concept of insulation in Fourth Grade Science. Emphasize that to see a substance as an insulator is to view it in a very different way, asking how much it prevents instead of allows the flow of heat. Ask: Can you identify any materials that are good insulators? Guide students' search by informing them that such materials and equipment are in common use around the kitchen and in the preparation and preservation of food. Inform students that Styrofoam cups keep drinks hot or cold because they are good insulators. Inform them that pot holders, pizza boxes, thermoses, and winter coats are also good insulators.

Fifth Grade - Science - Lesson 11 - Expansion and Contraction

Objectives
Understand that substances expand when heated.
Understand that substances contract when cooled.
Understand that the thermometer works on the principle of contraction and expansion.

Materials
Drawing of a thermometer, attached (for transparency)

Suggested Books
Teacher Reference
Berger, Melvin. Solids, Liquids, and Gases: From Superconductors to the Ozone Layer. New York: G. P. Putnam's Sons, 1989.
Division of Curriculum Development Office of Science and Health, BCPS. STARS Elementary
Science Curriculum. Baltimore: Baltimore City Public Schools, 1991.
Hirsch, E. D. What Your 5th Grader Needs To Know. New York: Doubleday, 1993.

Teacher Background

In Fifth Grade Science, Lesson 1 dealt with 'Matter,' Lesson 2 dealt with 'Atoms,' Lesson 5 dealt with 'Molecules,' and Lesson 6 dealt with 'Physical and Chemical Change.' In Fourth Grade Science, 'The Properties of Matter,' was introduced. In Science in First Grade, 'The Three Phases of Matter,' and 'The Changing Phases of Water,' were presented. 'Phases of Matter' is presented in Reading Mastery 1V, Lessons 104, 105, and 106. 'Expansion,' is covered in Reading Mastery 1V, Lessons 10 and 110, and in Reading Mastery 111, Lessons 49, 50, and 65. 'Changing Phases,' is discussed in Reading Mastery 1V, in Lesson 109. 'Phases of Matter,' is presented in the Academic Core, Level 111. This lesson focuses on heat, contraction and expansion in matter. When heat energy is added to a substance, it causes the substance's molecules to move more quickly, and causes the substance to expand or grow bigger. When matter is cooled, the opposite happens. The molecules slow down, and the substance contracts, or grows smaller. The thermometer, an instrument for measuring temperature, is a perfect example of the principle of expansion and contraction of matter. It is a simple, practical instrument whose functioning is closely related to the phenomenon it measures, temperature. A sealed glass tube contains a substance that expands when heated and contracts when cooled. The glass tube or the frame which protects it bears a gradually increasing scale. The temperature is indicated by the part of the scale reached by the top of the column of liquid.

Procedure

Ask students if they have ever had difficulty opening the lid of a peanut butter jar? Ask: What do you do when this happens? Explain that there is a little trick that one can perform in this situation, that by turning the jar lid-down into hot water, one can unscrew the lid much more easily. Ask for volunteers to explain why the lid becomes easier to open after it has been heated. Explain that when heat energy is added to a substance, in this case the lid cover, that substance expands or grows bigger. Explain further that the substance in question expands because the heat energy forces the molecules of that substance farther apart. Explain that as the lid cools, the reverse happens and the lid contracts or grows smaller. Emphasize that when substances are heated, they expand or grow bigger and when substances are cooled, they contract or grow smaller. Explain that this is true of most substances whether they are solids, liquids, or gases.

Students should be familiar with the thermometer from an introduction in earlier grades. Explain that the thermometer is an instrument used by meteorologists or scientists who study weather to measure how cold or hot the air temperature of a day or night is. Explain that nurses and parents also use thermometers to measure the temperature of the human body. Project a transparency of the attached diagram showing the thermometer. Explain that the thermometer is a sealed glass tube (point to the sealed glass tube) with a gradually increasing scale (point to the scale) on the glass tube or on the frame that protects the tube. Ask: Would you use this thermometer for air or body temperature? (air) Why? (attached to board) Explain that within that tube is a mercury or colored alcohol column (point to the column). Explain that mercury and alcohol are used because they expand and contract quickly in response to the rise and fall in temperature. Explain that as the temperature of the air or the human body rises the liquid column in the sealed glass tube warms up, its molecules move rapidly, and the substance expands. Explain that as a result, the column (point to the column) rises in the tube. Explain also that the level of the mercury or alcohol falls due to contraction as a result of the cooling of the air or of the human body.

Tell students that the temperature reading is the number next to the horizontal line that the liquid has risen to. Ask: What is the reading on this thermometer? (70C) Explain that the temperature reading can be given in Celsius or Fahrenheit scales. Explain that the letter 'F' on the diagram stands for the Fahrenheit scale on the right of the glass tube. (Point to the letter 'F' and to the corresponding gradually increasing scale.) Explain also that the letter 'C' on the diagram stands for the Celsius scale on the left of the glass tube. (Point to the letter 'C' and the corresponding Celsius scale.) Explain that on the Fahrenheit scale water freezes at 32 and boils at 212. Point out that 0C and 32F are on the same line, and this is also the case for 100C and 212F. On the Celsius scale, 0 marks the freezing point of water and 100 marks its boiling point. Explain that the Celsius scale starts at 0. 0C is the melting point of ice, the freezing point of water. Emphasize that 0C does not mean the absence of heat energy.

Explain that temperatures may fall below freezing point 0C. In such cases, temperatures are represented by negative numbers such as, -30C or 30 degrees below freezing point. Explain however that the Celsius scale is based on measurements of water. It is divided into a hundred units from 0C, the freezing point of water, to 100C, water's boiling point. Emphasize that thermometers using either scale could go much higher or lower than the one represented in this diagram. Have students attempt an explanation of how the Fahrenheit scale got its name. Have students relate their experience of winter temperatures. Explain that this scale got its name from its inventor, Fahrenheit, a German scientist who lived in the 1700s. Ask students to explain how the Celsius scale got its name. Explain that it got its name from its inventor, Celsius, a Swedish scientist who like Fahrenheit lived in the 1700s.

Additional Activities

You may ask your students to do the following.
1. Some bridges have expansion/contraction joints in them. Why? What would happen if these did not exist? (Such joints are either empty space or materials such as rubber which allow the bridge to expand and contract without causing damage. Floor tiles have a similar feature for that very same reason.)
2. Investigate how a hand-held thermometer used for taking body temperature works. Also, find out what is "normal" body temperature.
3. Observe thermometers in a public building such as a school or at a business office, and explain why it is placed where it is. Remember that hot air tends to rise and cool air tends to sink.
 

Fifth Grade - Science - Lesson 12 - Water

Objectives
Recall the chemical composition of water.
Understand that water is a special case: it expands when it changes from a liquid to a solid.
Understand the freezing and boiling points of water in degrees Celsius and Fahrenheit.

Suggested Books
Teacher Reference
Berger, Melvin. Solids, Liquids, and Gases: From Superconductors to the Ozone Layer. New York: G. P. Putnam's Sons, 1989.
Hirsch, E. D. What Your 5th Grader Needs To Know. New York: Doubleday, 1993.

Teacher Background
In Fifth Grade Science, Lesson 1 dealt with 'Matter,' Lesson 2 dealt with 'Atoms,' Lesson 5 dealt with 'Molecules,' and Lesson 6 dealt with 'Physical and Chemical Change.' In Fourth Grade Science 'The Properties of Matter' was introduced. In Science in First Grade 'The Three Phases of Matter,' and 'The Changing Phases of Water,' were presented. 'Phases of Matter' is presented in Reading Mastery 1V, Lessons 104, 105, and 106. 'Expansion,' is covered in Reading Mastery 1V, Lessons 10 and 110, and in Reading Mastery 111, Lessons 49, 50, and 65. 'Changing Phases,' is discussed in Reading Mastery 1V, in Lesson 109. 'Phases of Matter,' is presented in the Academic Core, Level 111. In Second Grade Science, 'The Water Cycle' was discussed including water vapor, evaporation, and condensation. Water is a compound. Its chemical formula is H 2O. H is the chemical symbol for hydrogen. O is the chemical symbol for oxygen. The chemical formula states that two hydrogen atoms and one oxygen atom form one molecule of water. Liquid water freezes at 0C or 32F. If energy is added to a block of ice at that temperature, it melts. If energy is removed, it freezes. The boiling point of water is 100C or 212F.

Procedure
Start by telling students that this lesson is about water in relation to some of the topics discussed in Chemistry so far in Fifth Grade. Recall that formulas are a kind of shorthand used by chemists to name substances. Ask: What is the chemical formula of water? (H2O) Write the formula of water on the board or on chart paper. Ask: What does the formula mean? (that water is made up of hydrogen and oxygen atoms) Ask: What is the name given to substances made out of two different elements which have come together as in the case of water? (a compound) Explain that the formation of water from the coming together of two elements is a change. Ask: Is it a chemical change or a physical change? (chemical change) Ask: Why is it a chemical and not a physical change? (because a wholly new substance, water is the result) Recall that students studied chemical symbols in Chemistry in Fifth Grade. Ask: What element is H the symbol of? (hydrogen) Ask: What element is O a symbol of? (oxygen) Draw attention to the subscript 2 to the right of and slightly lower than H and to the left of O. Ask: To which symbol is the subscript 2 related? (H) Ask: What does the subscript 2 mean? (that two hydrogen atoms make up every water molecule) Ask: Why is there no subscript after O? (one atom of oxygen is present in a water molecule and only numbers larger than one are used in a formula) Ask: What is the name given to water in the solid state? (ice) Ask: What is the name given to water in the gaseous state? (steam) Remind students that every substance has its own boiling and freezing temperatures or points. Ask: At what temperature does water freeze? (0C or 32F) Ask: What is the boiling point of water? (100C or 212F) Recall that Lesson 11 deals with contraction and expansion. Ask: What is expansion? (increase in size) Ask: What is contraction? (decrease in size) Ask: How is heat related to expansion? (Heat causes the molecules to vibrate more quickly and causes a substance to expand.) Ask: How is heat related to contraction? (When heat is removed molecules move less and a substance contracts.) Ask students to reflect on their knowledge of ice, of water in ice trays in the freezer at home, of water frozen in bottles left accidentally in the freezer, and ask: When water freezes does it contract or expand? (expands) Explain that broken bottles in the refrigerator, broken water pipes in the winter, and bulging surfaces of ice cubes are signs of expansion in ice. Ask: Does water obey the rule which suggests substances contract when frozen, or is it an exception? (exception) Finally, tell students that in the following lesson, Lesson 13, they will learn of a process whereby water can be made pure based on the principle that every substance has its own boiling temperature. Explain that in that process, impure water is heated and the impurities separated.

Fifth Grade - Science - Lesson 13 - Distillation

Objectives
Understand the process of distillation.
Recall that each substance has its boiling point.

Materials
Drawing of the distillation process, attached, (for transparency)

Suggested Books
Teacher Reference
Berger, Melvin. Solids, Liquids, and Gases: From Superconductors to the Ozone Layer. New York: G. P. Putnam's Sons, 1989.
Hirsch, E. D. What Your 5th Grader Needs To Know. New York: Doubleday, 1993.

Teacher Background

In Fifth Grade Science, Lesson 1 dealt with 'Matter,' Lesson 2 dealt with 'Atoms,' Lesson 5 dealt with 'Molecules,' and Lesson 6 dealt with 'Physical and Chemical Change.' In Fourth Grade Science, 'The Properties of Matter,' was introduced. In Science in First Grade, 'The Three Phases of Matter,' and 'The Changing Phases of Water,' were presented. 'Phases of Matter' is presented in Reading Mastery 1V, Lessons 104, 105, and 106. 'Expansion,' is covered in Reading Mastery 1V, Lessons 10 and 110, and in Reading Mastery 111, Lessons 49, 50, and 65. 'Changing Phases,' is discussed in Reading Mastery 1V, in Lesson 109. 'Phases of Matter,' is presented in the Academic Core, Level 111. This lesson focuses on distillation, the process of separating the components of liquid mixtures based on their separate boiling points. The principle that each substance has its own boiling point was introduced in Lesson 9.

Procedure
Ask students: What is distilled water? (water that has been boiled and condensed to remove impurities) Then, ask: What makes distilled water so special? (its purity) Emphasize that distilled water is water from which impurities have been removed. Explain impurities as all that tends to make water less than fit for human consumption. Tell students that salt is probably the most common of these impurities, but that impurities may include carbon dioxide. Explain that water may be purified by a process known as distillation and that water is the substance most often distilled. During distillation different substances are separated by boiling. Tell students that they are about to learn about the process of distillation. Recall that they learned from Lesson 9 that each substance has its own boiling point, then, on the transparency of the attached drawing, point to the flask on the left, and ask: What is in that flask? (impure water) Explain that impure water is water in which other substances have been mixed. Explain that impure water in this case is a mixture of at least two substances, water and salt, for example. Ask: How would you define boiling point? (temperature at which a substance boils or turns to vapor) Explain that since the flask on the left contains at least two substances one of which is water, there will be at least two different temperatures at which these substances turn to vapor. Ask: At what temperature does water boil? (100C or 212F) Point to the flame in the diagram and ask: What happens to water as the temperature of the impure water in the flask begins to rise? (water turns to steam) Explain that the flask in which water is boiled usually contains a thermometer in its top. This thermometer tells the temperature of the steam contained in the flask. Ask: Why would it be necessary to use a thermometer? (so as to avoid reaching a temperature at which any impurities condense, too)

Point to the cooling tube and explain that it has two walls, an inner wall in which steam cools, and an outer wall which contains cold water (point to cold water). This cold water is pumped in from connected tanks. The cold water is used to cool the steam in the inner wall of the cooling tube. Explain that the steam in the inner wall of the cooling tube loses its heat across this wall. Ask: What is the process (studied in Lesson 10) by which heat is transferred across a solid? (conduction) Explain that the cold water which was used to cool the steam in the tube is now cool water (point it out) and is pumped out into another tank. Point to the inner wall and explain that the steam within it continues to lose heat. Ask: What happens if water vapor continues to cool? (It condenses or turns to liquid water.) Explain that after condensation, the liquid water that results is distilled or purified. Point to the flask on the right and explain that this is where distilled water collects. Ask: What has happened to the impurities that had been mixed with the water? (They stayed in the flask on the left.) Ask: Why did the impurities not remain with the water? (They had higher boiling points and so water evaporated at a lower temperature than the one at which the impurities might have.) Emphasize that the process of separating components of liquid mixtures such as impure water by boiling is called distillation. Explain that this process produces drinking water for much of the world's population. Distilled water is also used in hospitals and in automobile batteries. Finally, explain that this diagram shows the distillation process in a laboratory setting. In an industrial setting, the water which has been used to cool the steam in the cooling tube is then distilled. Since it has itself been warmed up from cooling the hot steam in the cooling tube, it requires less energy to bring it to its boiling point. By reusing water warmed up in this way, energy is saved.

Bibliography

Teacher Reference
Berger, Melvin. Solids, Liquids, and Gases: From Superconductors to the Ozone Layer. New York: G. P. Putnam's Sons, 1989. (0-399-21731-2)
Division of Curriculum Development Office of Science and Health, BCPS. STARS Elementary
Science Curriculum. Baltimore: Baltimore City Public Schools, 1991.
*Hirsch, E. D. What Your 5th Grader Needs To Know. New York: Doubleday, 1993.(0-385-31464-7)