What kind of change will u observe in a piece of metal when you heat it??
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Heating and Cooling Matter
Introduction
Heat is a form of energy. We perceive cold as the lack of heat. We heat and cool things every day. Materials will interact with heat and sometimes can change state.
Materials and objects can get warmer when heated.
A pot of water gets hotter as you heat it on the stove.
An object put on a hot radiator gets hotter.
Dark objects placed in bright sunlight can absorb the sunlight and heat up.
Materials and objects can get colder when heat is removed.
Objects placed in the refrigerator or freezer will lose heat and get colder.
Materials placed outdoors in the wintertime when it is cold will lose heat and get colder.
Placing an object in cold water will cause the object to lose heat.
Materials can change state as a result of heating or cooling.
Examples of state changes caused by heating.
When ice is heated it melts and becomes liquid water.
When liquid water is heated until it boils it turns into a gas.
Water and perfume when they are heated will evaporate producing gas (called vapor) which dissolves in air.
Examples of state changes caused by cooling.
When liquid water is cooled to the freezing point it will form ice.
Water vapor dissolved in the air will condense when it is cold forming snow or frost which are solids.
Water vapor dissolved in the air will condense on a cold glass of lemonade to form droplets of liquid water.
Materials
ice cubes
water
rubbing alcohol
dry ice (if it is possible to obtain it)
Science Journals
Procedure
1. Students take an ice cube and place it on a surface. They observe the ice cube for signs that it is changing state. These observations are written in their Science Journals.
2. A container of water is placed in the freezer and observed over a period of hours. Students observe the signs that it is changing state and record these in their Science Journals.
3. As a class demonstration, pieces of dry ice are placed in a prominent location. Students observe that dry ice (solid Carbon Dioxide) will change from a solid directly to a gas without passing through the liquid phase. Observations are written in their Science Journals.
Caution: Do not allow anyone to touch dry ice with their bare skin. It is best if dry ice is handled only by the teacher who will be wearing gloves. Inquire at a local supermarket if any products come shipped to the store in dry ice. A small piece can be wrapped in newspaper as insulation for transport to the classroom.
4. Students place a small quantity (a few drops) of rubbing alcohol on their hand. As it evaporates the skin will begin to feel cold. Students write their observations in their Science Journals.
Results
1. Students have written about changes of state caused by heating or cooling among the materials they studied. These results are written in their Science Journals.
2. Students relate the change in state process to the addition of heat to the substance (as in the evaporation of alcohol) or the removal of heat from the substance (as in the freezing of water). For example, "The water froze because the water lost enough heat to cause a change in state from liquid to solid."
3. Students make a table of results in their Science Journal. The table lists each of the materials studied, whether it was heated or cooled, and what happened as a result of the heating and cooling.
Introduction
Heat is a form of energy. We perceive cold as the lack of heat. We heat and cool things every day. Materials will interact with heat and sometimes can change state.
Materials and objects can get warmer when heated.
A pot of water gets hotter as you heat it on the stove.
An object put on a hot radiator gets hotter.
Dark objects placed in bright sunlight can absorb the sunlight and heat up.
Materials and objects can get colder when heat is removed.
Objects placed in the refrigerator or freezer will lose heat and get colder.
Materials placed outdoors in the wintertime when it is cold will lose heat and get colder.
Placing an object in cold water will cause the object to lose heat.
Materials can change state as a result of heating or cooling.
Examples of state changes caused by heating.
When ice is heated it melts and becomes liquid water.
When liquid water is heated until it boils it turns into a gas.
Water and perfume when they are heated will evaporate producing gas (called vapor) which dissolves in air.
Examples of state changes caused by cooling.
When liquid water is cooled to the freezing point it will form ice.
Water vapor dissolved in the air will condense when it is cold forming snow or frost which are solids.
Water vapor dissolved in the air will condense on a cold glass of lemonade to form droplets of liquid water.
Materials
ice cubes
water
rubbing alcohol
dry ice (if it is possible to obtain it)
Science Journals
Procedure
1. Students take an ice cube and place it on a surface. They observe the ice cube for signs that it is changing state. These observations are written in their Science Journals.
2. A container of water is placed in the freezer and observed over a period of hours. Students observe the signs that it is changing state and record these in their Science Journals.
3. As a class demonstration, pieces of dry ice are placed in a prominent location. Students observe that dry ice (solid Carbon Dioxide) will change from a solid directly to a gas without passing through the liquid phase. Observations are written in their Science Journals.
Caution: Do not allow anyone to touch dry ice with their bare skin. It is best if dry ice is handled only by the teacher who will be wearing gloves. Inquire at a local supermarket if any products come shipped to the store in dry ice. A small piece can be wrapped in newspaper as insulation for transport to the classroom.
4. Students place a small quantity (a few drops) of rubbing alcohol on their hand. As it evaporates the skin will begin to feel cold. Students write their observations in their Science Journals.
Results
1. Students have written about changes of state caused by heating or cooling among the materials they studied. These results are written in their Science Journals.
2. Students relate the change in state process to the addition of heat to the substance (as in the evaporation of alcohol) or the removal of heat from the substance (as in the freezing of water). For example, "The water froze because the water lost enough heat to cause a change in state from liquid to solid."
3. Students make a table of results in their Science Journal. The table lists each of the materials studied, whether it was heated or cooled, and what happened as a result of the heating and cooling.
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