Whether students plan on becoming geologists, biologists, nanotechnologists, or astrophysicists, they will all need to have an operational understanding of the laws of physics that govern our universe. In all disciplines of science, physics is the foundation which we use to describe the interaction between objects and the world around us. It is important then, for students to have a firm grasp in understanding the laws of forces and motion, which can be used to describe phenomena from the subatomic level to the creation and expansion of the cosmos.
Two of the best websites I have used in my classroom to help students understand force and motion is the Physics Education Technology (http://phet.colorado.edu/simulations/index.php?cat=Motion) and online physics games (http://www.physicsgames.net/). The PhET website provides various interactive simulations for students to manipulate and measure the forces and motions of objects and related phenomena. To demonstrate force and motion, students can manipulate various objects and view measurements of those forces through graphs and various recording devices offered in the simulation. Also, students can change variables in the simulations such as mass, friction, location, etc to see how objects react under varying conditions. For example, in the “Energy Skate Park” simulation a skater is placed on a ramp and graphs can be displayed showing the kinetic and potential energy of the skater as he moves along the ramp. Students have the ability to change the shape of the ramp, skaters, friction, location, and display different types of graphs. These simulations are fantastic for force and motion demonstrations either as whole class discussion, in small groups, or individually, and I have implemented them in all three situations.
Another great website my students love is a compilation of physics games in which students are challenged to solve a problem or overcome a series of obstacles as they move through various levels of increasing difficulty. These games are highly engaging and require students to think critically in order to be successful in the virtual world. For example, in the game “Cover Orange” the goal is the find a protected location for the orange(s) to avoid being rotted by the storm cloud. In order to do this, obstacles must be overcome and objects must be moved to save the oranges. These obstacles become increasingly more difficult as the game progresses requiring higher level thought processes to solve the problem and protect the orange. These games can be used in small groups or individually. I find that using the games in with pairs of students works the best as students can work together to solve the challenge. These games require students to have a basic understanding of force and motion to move the objects on the screen to win the challenge of that particular level.
I use the motion simulations from the PhET website frequently when teaching friction, gravity, Newton's Laws of Motion, periodic motion, and potential and kinetic energy. First I use the simulation as a demonstration model when covering the topic, then I may provide a laptop to groups of 2 or 3 students to work on together changing variables and observing reactions of the objects. I also use the PhET simulations in review for tests, as each student will get a laptop and questions to answer requiring them to manipulate the simulation and analyze the graphs in order to answer the questions.
The physics games can either be used as a station for students who finish work early, or as an extension lesson all it's own. The students work in pairs and choose one of the games. They play the game until they are unable to continue to any higher level, or if they finish the game. At the end of their playing session, students are to write a summary of the challenges they faced, the forces they had to apply or overcome, as well as some of the types of motion they recognized. Students view this activity as fun and don't realize they are actually applying some of the things they have learned in the process.
These are not the only websites that will enhance student interest in science, but these are two that I implement in my classroom. Other websites which can serve a similar purpose are listed below along with a link to those sites.
Amusement Park Physics. http://www.learner.org/interactives/parkphysics/
Forces in Action. http://www.bbc.co.uk/schools/scienceclips/ages/10_11/forces_action.shtml
Galileo Drops the Ball. http://www.seed.slb.com/labcontent.aspx?id=10206&terms=galileo
Laws of Motion. http://www.neok12.com/Laws-of-Motion.htm
Newton’s Laws of Motion.http://science.discovery.com/interactives/literacy/newton/newton.html
The challenges with using technology in the classroom is that the teacher has to have access to computers, and also count on the fact that the technology will work when they need it to. Also, one may face criticism from parents or administration who may view the students playing games as not instructionally driven, however it you are able to produce evidence that their learning is applicable to these games and that it meets state standards then hopefully the parents and administration will be supportive.
Sunday, June 13, 2010
Saturday, May 29, 2010
An Exploration in Heat Transfer
Heat is the measure of the internal energy of a substance, in which the process of increasing the internal energy is heating the substance, and the process of decreasing the internal temperature is cooling the substance. In order for heat energy to flow, a temperature gradient must exist. When energy flows between substances of different temperatures, heat has been transferred from the substance of higher temperature to the substance of lower temperature. Heat can be transferred between substances by the processes of convection, conduction, or radiation. Convection is the movement of heat within a fluid, such as air or water, conduction is the movement of heat between two solid objects through direct contact of the molecules, and radiation is the movement of heat through space via electromagnetic waves (Tillery, Enger, & Ross, 2008).
In exploring heat transfer I was tasked with testing materials which would inhibit or slow the transfer of heat energy via conduction by covering the top of coffee mugs filled with hot water and comparing the temperature difference from zero minutes to 30 minutes. Materials which are effective in slowing the transfer of heat are known as insulators. For this investigation I chose to use the common household items newspaper, a plastic lid, cotton cloth, and cardboard, each with a thickness of 3mm to ensure I was only testing the effectiveness of the material itself since varying thicknesses could affect the results. I also established a control mug with no material covering the top to use as a comparison. To counteract any heat loss through the mug as opposed to the tested materials, I first filled each mug with hot water and placed them in the microwave for one minute to heat the mugs then emptying them prior to filling each mug with 400mL of boiling water. The ambient temperature of the room was 26 degrees Celsius. A starting temperature of 92 degrees Celsius was recorded and each mug was covered with the different materials being tested verifying that there were no spaces between the mug and the material for heat to escape.
My hypothesis was that the plastic lid would be the most effective insulator as it is less porous than the other materials thereby increasing the likelihood of the heat remaining trapped in the coffee mug. Since heat propagates across a gradient from higher temperatures to lower temperatures the heat from the 92 degree Celsius water wants to flow in direction of the 26 degree Celsius air surrounding the mug.
Upon analyzing the results (see data table below), I rejected my hypothesis that the plastic lid would be the best insulator of the materials tested. The data shows that the cardboard was the most effective insulator resulting in a decrease of 24 degrees Celsius over the 30 minute period compared with a 27 degree Celsius decrease in temperature for the plastic lid. My reasoning is that the plastic is a solid material with a dense arrangement of molecules which allow for the easy conduction of heat evenly throughout the material. The cardboard however has spaces of air between the layers which do not allow the heat to transfer as easily as the air molecules in the spaces are less dense making it difficult for the heat to transfer across the material. By comparison, the control mug with no material decreased 38 degrees Celsius allowing the heat to flow freely from the mug into the surrounding air. Overall, there was only a difference of 4 degrees Celsius between all of the materials used.
Perhaps letting the experiment run for an hour would produce a greater disparity between results of the materials thereby making the findings more conclusive. The temperature difference between the control mug and the other mugs with insulators becomes quite evident demonstrating that any material will retard the transfer of heat to some degree; however some materials are more effective than others.
Another variation for this experiment would be to use heated solids as opposed to liquids such as pancakes. Pancakes notoriously lose their heat quickly and an interesting investigation may be to see which materials are able to keep a pancake the hottest over a period of 30 minutes. An initial pancake temperature can be recorded then wrap each pancake with a different material and record a final temperature at the end of 30 minutes. I would expect any material with air pockets embedded in it would be the most effective, and those materials too porous or too solid would create a larger heat gradient for the transfer of the heat energy.
The most challenging thing for me during this investigation was ensuring all of my variables were as controlled as possible so as any temperature difference could be accounted for as a result of the material being used and not an outside factor such as heat loss through the mug, or varying thicknesses of the materials.
In conducting heat transfer experiments in my classroom using a structured inquiry format, students use three Styrofoam cups starting with different temperatures of water. One is the control using room temperature water, the second is ice water, and the third is boiling water. Students record the temperature of each cup every five minutes for an hour. After recording their data, the students create a triple line graph of their data, and they should find that the control cup does not change, the ice water cup should increase, and the boiling water should decrease. When the students analyze the graph they should come to the conclusion that if we were to extend the experiment over several hours or days, that the temperature of all three cups should be the same temperature of the air surrounding the cups due to heat wanting to reach a point of equilibrium between substances.
Temperature experiments are excellent activities in getting students to understand the concept of heat transfer as measurements can be easily recorded and results are fairly clear. These experiments also help reinforce the scientific process in making good observations, recording data, and drawing inferences and conclusions based on the results they achieve. Students have a common misconception that colder substances permeate hotter substances such as when they hold an ice cube in their hands, many will note that the cold from the ice goes into their hands making them feel colder. After conducting these experiments, the students are able to realize that no matter how heat is transferred, it will always flow from a region of higher temperature to a region of lower temperature.
Data Table
Material Temp 0 mins (oC) Temp 30 mins (oC) Temp Difference (oC)
Control (no material) 92 54 -38
Newspaper 3mm 92 67 -25
Plastic lid 3mm 92 65 -27
Cotton cloth 3mm 92 66 -26
Cardboard 3mm 92 68 -24
Ambient temperature surrounding the mugs is 26 oC.
In exploring heat transfer I was tasked with testing materials which would inhibit or slow the transfer of heat energy via conduction by covering the top of coffee mugs filled with hot water and comparing the temperature difference from zero minutes to 30 minutes. Materials which are effective in slowing the transfer of heat are known as insulators. For this investigation I chose to use the common household items newspaper, a plastic lid, cotton cloth, and cardboard, each with a thickness of 3mm to ensure I was only testing the effectiveness of the material itself since varying thicknesses could affect the results. I also established a control mug with no material covering the top to use as a comparison. To counteract any heat loss through the mug as opposed to the tested materials, I first filled each mug with hot water and placed them in the microwave for one minute to heat the mugs then emptying them prior to filling each mug with 400mL of boiling water. The ambient temperature of the room was 26 degrees Celsius. A starting temperature of 92 degrees Celsius was recorded and each mug was covered with the different materials being tested verifying that there were no spaces between the mug and the material for heat to escape.
My hypothesis was that the plastic lid would be the most effective insulator as it is less porous than the other materials thereby increasing the likelihood of the heat remaining trapped in the coffee mug. Since heat propagates across a gradient from higher temperatures to lower temperatures the heat from the 92 degree Celsius water wants to flow in direction of the 26 degree Celsius air surrounding the mug.
Upon analyzing the results (see data table below), I rejected my hypothesis that the plastic lid would be the best insulator of the materials tested. The data shows that the cardboard was the most effective insulator resulting in a decrease of 24 degrees Celsius over the 30 minute period compared with a 27 degree Celsius decrease in temperature for the plastic lid. My reasoning is that the plastic is a solid material with a dense arrangement of molecules which allow for the easy conduction of heat evenly throughout the material. The cardboard however has spaces of air between the layers which do not allow the heat to transfer as easily as the air molecules in the spaces are less dense making it difficult for the heat to transfer across the material. By comparison, the control mug with no material decreased 38 degrees Celsius allowing the heat to flow freely from the mug into the surrounding air. Overall, there was only a difference of 4 degrees Celsius between all of the materials used.
Perhaps letting the experiment run for an hour would produce a greater disparity between results of the materials thereby making the findings more conclusive. The temperature difference between the control mug and the other mugs with insulators becomes quite evident demonstrating that any material will retard the transfer of heat to some degree; however some materials are more effective than others.
Another variation for this experiment would be to use heated solids as opposed to liquids such as pancakes. Pancakes notoriously lose their heat quickly and an interesting investigation may be to see which materials are able to keep a pancake the hottest over a period of 30 minutes. An initial pancake temperature can be recorded then wrap each pancake with a different material and record a final temperature at the end of 30 minutes. I would expect any material with air pockets embedded in it would be the most effective, and those materials too porous or too solid would create a larger heat gradient for the transfer of the heat energy.
The most challenging thing for me during this investigation was ensuring all of my variables were as controlled as possible so as any temperature difference could be accounted for as a result of the material being used and not an outside factor such as heat loss through the mug, or varying thicknesses of the materials.
In conducting heat transfer experiments in my classroom using a structured inquiry format, students use three Styrofoam cups starting with different temperatures of water. One is the control using room temperature water, the second is ice water, and the third is boiling water. Students record the temperature of each cup every five minutes for an hour. After recording their data, the students create a triple line graph of their data, and they should find that the control cup does not change, the ice water cup should increase, and the boiling water should decrease. When the students analyze the graph they should come to the conclusion that if we were to extend the experiment over several hours or days, that the temperature of all three cups should be the same temperature of the air surrounding the cups due to heat wanting to reach a point of equilibrium between substances.
Temperature experiments are excellent activities in getting students to understand the concept of heat transfer as measurements can be easily recorded and results are fairly clear. These experiments also help reinforce the scientific process in making good observations, recording data, and drawing inferences and conclusions based on the results they achieve. Students have a common misconception that colder substances permeate hotter substances such as when they hold an ice cube in their hands, many will note that the cold from the ice goes into their hands making them feel colder. After conducting these experiments, the students are able to realize that no matter how heat is transferred, it will always flow from a region of higher temperature to a region of lower temperature.
Data Table
Material Temp 0 mins (oC) Temp 30 mins (oC) Temp Difference (oC)
Control (no material) 92 54 -38
Newspaper 3mm 92 67 -25
Plastic lid 3mm 92 65 -27
Cotton cloth 3mm 92 66 -26
Cardboard 3mm 92 68 -24
Ambient temperature surrounding the mugs is 26 oC.
Sunday, May 16, 2010
Mass, Speed, and Momentum: Using Guided Inquiry in the Classroom
The type of inquiry used in the classroom is determined by the amount of information the teacher provides to the students. In using a guided inquiry format, the teacher simply provides the students with a research question, and it is up to the students to determine the method of testing and drawing conclusions from the results of the data collected (Banchi and Bell, 2008). For example, I had the opportunity to conduct a guided inquiry investigation being provided on the the question "How does the steepness of a slope and mass affect a collision outcome?"
I realized I needed to set up a model to demonstrate a scenario in which an object on variable slopes could collide with another object at the bottom of the slope. I decided to use a small toy truck (8 grams), a 27 cc wooden block (5 grams), a cardboard ramp (27.5 cm), three books, a meter stick, and a calculator. I also wanted to determine if the amount of mass could influence the collision outcome so I used a large bolt (12 grams) that could be added to the toy truck. I set up the model with one end of the ramp resting on a book, then simulate the collision by releasing the toy truck from the top of ramp and impacting the wood block on the floor at the base of the ramp. I then measured the distance the block traveled after the collision with the truck five times and calculated the average. I repeated this with ramp at a height of 3 cm, 6 cm, and 9 cm. I then duplicated that process with the 12 g mass attached to the truck and recorded the data from those trials to determine if the amount of mass made a difference in the distance.
Once I determined how I was going to test the research question, I needed to form a hypothesis. My hypothesis is that as the ramp height increases, the distance the block is moved will also increase. Secondly, the added mass will also increase the distance when compared with the data from the toy truck alone. The increase in distance will be a result of the increased speed the truck is able to generate as the ramp height increases thereby impacting the block with a greater force. Subsequently the added mass will provide the truck with more momentum thereby increasing the distance of the block after impact.
The results of the investigation confirm my hypothesis as the data shows that the average distance of the block increased from 16.4cm to 31.8cm as the ramp height increased from 3cm to 9cm for the toy truck alone with a mass of 8g. Similar results were achieved when an additional 12g of mass were added as the distance of the block increased from 26.4cm to 46.6cm when the ramp height increased from 3cm to 9cm. When displayed in a graph, the disparity between the averages in distance at each ramp height comparing truck only and added mass becomes more evident in this visual representation. This leads me to conclude that increasing the height of the ramp and added mass increases the speed of the truck thereby increasing the amount of force at impact due to the added momentum. Since momentum is directly affected by the mass and speed of an object, the evidence from the investigation confirms that claim (Tillery, Enger, and Ross, 2008, p 43).
In conducting this guided inquiry investigation I had to be very careful about setting up my testing model appropriately in order to achieve quantifiable results that would either confirm or reject my hypothesis. In keeping with the engineering design process model I realized the need, brainstormed different design options, selected a design, planned the investigation, created the model, then made necessary improvements along the way (TEACH, 2010). This type of inquiry allows freedom of creativity in constructing a testing model according to my own ideas, and not necessarily the ideas or guidelines imposed by someone else. I actually use this very same investigation in my classroom when studying Newton’s second law of motion as a structured inquiry lesson. The investigation I conducted above is divided into two separate investigations with the first altering the height of the ramp to impact an object, and the second using a fixed ramp height with additional mass added to the vehicle. In both instances, the students are able to determine that the force of the vehicle (momentum) increases as the speed and mass are increased. The students really enjoy both of these investigations as the real world implications are limitless. Relating this to any object that is moving will apply and further reinforce the concept of mass and speed determining the momentum of an object.
I like the concept of using this as a guided inquiry lesson, however many of my students come to fifth grade lacking fluency in the scientific processes necessary to carry out an investigation such as this. For this reason I use structured inquiry in conducting a complex investigation like this one due to the fact there are numerous variables which could affect the outcome thereby rendering the data collected insignificant for achieving the level of understanding of the content. With a significant amount of guidance and intervention as they develop their tests, however, the students should be able to successfully work through the investigation to achieve the desired results.
Guided inquiry allows the students freedom of creativity in designing and carrying out an investigation to find answers to a question provided by the teacher. The teacher’s role during the process is one of support, intervention, and frequent questioning in order to ensure scientific integrity in extending the students thinking and application of the scientific process. It is important to keep in mind however, that the experiment is a product of the students’ knowledge, and too much intervention would then become a product of the teacher. Students need to experience science to truly understand science, and balancing creativity with guidance through the guided inquiry process allows them to do just that.
References:
Banchi, H., & Bell, R. (2008). The many levels of inquiry. Science & Children, 46(2), 26–29.
TEACH Engineering: The Engineering Design Process: Retrieved May 16, 2010 from http://www.teachengineering.org/engrdesignprocess.php
Tillery, B., Enger, E., & Ross. F. (2008). Integrated science (4th ed.). New York: McGraw-Hill.
I realized I needed to set up a model to demonstrate a scenario in which an object on variable slopes could collide with another object at the bottom of the slope. I decided to use a small toy truck (8 grams), a 27 cc wooden block (5 grams), a cardboard ramp (27.5 cm), three books, a meter stick, and a calculator. I also wanted to determine if the amount of mass could influence the collision outcome so I used a large bolt (12 grams) that could be added to the toy truck. I set up the model with one end of the ramp resting on a book, then simulate the collision by releasing the toy truck from the top of ramp and impacting the wood block on the floor at the base of the ramp. I then measured the distance the block traveled after the collision with the truck five times and calculated the average. I repeated this with ramp at a height of 3 cm, 6 cm, and 9 cm. I then duplicated that process with the 12 g mass attached to the truck and recorded the data from those trials to determine if the amount of mass made a difference in the distance.
Once I determined how I was going to test the research question, I needed to form a hypothesis. My hypothesis is that as the ramp height increases, the distance the block is moved will also increase. Secondly, the added mass will also increase the distance when compared with the data from the toy truck alone. The increase in distance will be a result of the increased speed the truck is able to generate as the ramp height increases thereby impacting the block with a greater force. Subsequently the added mass will provide the truck with more momentum thereby increasing the distance of the block after impact.
The results of the investigation confirm my hypothesis as the data shows that the average distance of the block increased from 16.4cm to 31.8cm as the ramp height increased from 3cm to 9cm for the toy truck alone with a mass of 8g. Similar results were achieved when an additional 12g of mass were added as the distance of the block increased from 26.4cm to 46.6cm when the ramp height increased from 3cm to 9cm. When displayed in a graph, the disparity between the averages in distance at each ramp height comparing truck only and added mass becomes more evident in this visual representation. This leads me to conclude that increasing the height of the ramp and added mass increases the speed of the truck thereby increasing the amount of force at impact due to the added momentum. Since momentum is directly affected by the mass and speed of an object, the evidence from the investigation confirms that claim (Tillery, Enger, and Ross, 2008, p 43).
In conducting this guided inquiry investigation I had to be very careful about setting up my testing model appropriately in order to achieve quantifiable results that would either confirm or reject my hypothesis. In keeping with the engineering design process model I realized the need, brainstormed different design options, selected a design, planned the investigation, created the model, then made necessary improvements along the way (TEACH, 2010). This type of inquiry allows freedom of creativity in constructing a testing model according to my own ideas, and not necessarily the ideas or guidelines imposed by someone else. I actually use this very same investigation in my classroom when studying Newton’s second law of motion as a structured inquiry lesson. The investigation I conducted above is divided into two separate investigations with the first altering the height of the ramp to impact an object, and the second using a fixed ramp height with additional mass added to the vehicle. In both instances, the students are able to determine that the force of the vehicle (momentum) increases as the speed and mass are increased. The students really enjoy both of these investigations as the real world implications are limitless. Relating this to any object that is moving will apply and further reinforce the concept of mass and speed determining the momentum of an object.
I like the concept of using this as a guided inquiry lesson, however many of my students come to fifth grade lacking fluency in the scientific processes necessary to carry out an investigation such as this. For this reason I use structured inquiry in conducting a complex investigation like this one due to the fact there are numerous variables which could affect the outcome thereby rendering the data collected insignificant for achieving the level of understanding of the content. With a significant amount of guidance and intervention as they develop their tests, however, the students should be able to successfully work through the investigation to achieve the desired results.
Guided inquiry allows the students freedom of creativity in designing and carrying out an investigation to find answers to a question provided by the teacher. The teacher’s role during the process is one of support, intervention, and frequent questioning in order to ensure scientific integrity in extending the students thinking and application of the scientific process. It is important to keep in mind however, that the experiment is a product of the students’ knowledge, and too much intervention would then become a product of the teacher. Students need to experience science to truly understand science, and balancing creativity with guidance through the guided inquiry process allows them to do just that.
References:
Banchi, H., & Bell, R. (2008). The many levels of inquiry. Science & Children, 46(2), 26–29.
TEACH Engineering: The Engineering Design Process: Retrieved May 16, 2010 from http://www.teachengineering.org/engrdesignprocess.php
Tillery, B., Enger, E., & Ross. F. (2008). Integrated science (4th ed.). New York: McGraw-Hill.
Saturday, April 10, 2010
Structured Inquiry: A Reflection
Ideally, conducting science experiments in a classroom setting should consist of a question being posed based on an observation and the students will work together to figure out a way to test it to achieve valid results. However the reality of the situation is that many students, particularly at the elementary level, lack the scientific process skills that would allow them to conduct such an open inquiry investigation to achieve valid results. A structured inquiry format following the 5 E process (Engagement, Exploration, Explanation, Extension, and Evaluation) provides students with a question to answer, allows students to formulate a hypothesis, and provides materials for the students to conduct an investigation and collect data, then analyze their data to formulate a conclusion with valid results. The majority of the lesson is teacher guided, however the actual testing and data collection is done by the students. The main role of the teacher in this model is to provide guidance and reflection while the students work their way through the scientific inquiry process. This allows the students to become familiar with how science goes about seeking answers to questions and drawing inferences from the data that is collected.
In order to introduce our unit on microscopes and cells, I conducted a structured inquiry lesson on what types of materials have magnification abilities. I provided the students with a full water bottle, wax paper, hand lens, plastic bag, prism, and a clear marble to test their magnification properties on a section of newsprint. The students tested each material by holding it over the newsprint to see if the print was magnified in any way. The students collected data in a table where they would identify which materials magnified the newsprint and which ones were unable to magnify the newsprint. Once the data was collected, the students were then asked to compare each of the materials that magnified the newsprint to determine any similar properties or characteristics that allowed magnification. From those results, the students were then able to accept or reject their hypothesis and formulate a conclusion based on the magnifying materials as well as determine why those materials could magnify objects.
In reflecting on the effectiveness of the lesson, many students were able to determine that the full water bottle, hand lens, and clear marble successfully magnified the newsprint, though very few students were able to hypothesize that all three materials would have magnification ability. There seemed to be some ambiguity regarding the prism. Some students saw no changes to the appearance of the newsprint while others were able to angle the prism in such a way that the letters appeared to stretch and bend as they moved the prism over the newsprint. The determining characteristics identified by the students were the materials had to be clear, thick, and curved in order to magnify objects. This then led the students to the conclusion that the light is bending (refracting) as it passes through the material allowing the newsprint to be magnified. In discussing as a group following the lesson we identified a convex lens as meeting all of these criteria and can be used in telescopes, binoculars, magnifying glasses, reading glasses, and microscopes.
This lab will be used to assess the students’ understanding of what types of materials can magnify as well as their understanding the mechanism behind why those materials are able to magnify. This lab also verifies the students’ understanding of the investigative process to answer a question scientifically. Using this information will help me determine which students may need more reinforcement of the concept and which students have mastered the concept.
I feel the lesson went well in that the students were engaged from the beginning, worked well together in their groups to form a hypothesis, test their hypothesis, collect data, and draw a conclusion based on common characteristics from their data. This investigation really relies on students’ observation skills, proper data collection, and ability to find a connection between a seemingly random group of materials. I like the fact that we stopped frequently during the investigation to share, discuss, and reflect. The students benefit from this by gaining a better understanding of the scientific process.
In reviewing the lab sheets for the lesson, many students were able to grasp the concept that clear, thick, curved materials are able to act as a convex lens in refracting light giving it the ability to magnify. This becomes important for future lessons as we use microscopes to examine cells.
Going forward I think it will be necessary to examine the properties of the prism a little more with the students since this seemed to be a point of contention with many groups. Though the prism meets the criteria of being clear, thick, and can refract light, it is not a curved surface and does not meet the standard definition of a convex lens, which is the goal of the lesson. An extension of the lesson could be to examine the properties of the prism and determine why this occurs. Ultimately it boils down to how the prism refracts the light (refractive index) and since it is not curved the light does not intersect to a focal point enabling the newsprint to appear larger. This would be a great extension question to pose for those students who have a firm grasp of the magnification concept allowing them to analyze the properties of the prism and compare with the other materials such as the hand lens or water bottle.
The structured inquiry lesson following the 5 E process provides teacher guidance coupled with student testing to answer a question scientifically. I frequently use this type of lesson format when delivering content as there is ample opportunity to supplement the lesson with various media formats allowing me to cater to the different learning styles of my students.
In order to introduce our unit on microscopes and cells, I conducted a structured inquiry lesson on what types of materials have magnification abilities. I provided the students with a full water bottle, wax paper, hand lens, plastic bag, prism, and a clear marble to test their magnification properties on a section of newsprint. The students tested each material by holding it over the newsprint to see if the print was magnified in any way. The students collected data in a table where they would identify which materials magnified the newsprint and which ones were unable to magnify the newsprint. Once the data was collected, the students were then asked to compare each of the materials that magnified the newsprint to determine any similar properties or characteristics that allowed magnification. From those results, the students were then able to accept or reject their hypothesis and formulate a conclusion based on the magnifying materials as well as determine why those materials could magnify objects.
In reflecting on the effectiveness of the lesson, many students were able to determine that the full water bottle, hand lens, and clear marble successfully magnified the newsprint, though very few students were able to hypothesize that all three materials would have magnification ability. There seemed to be some ambiguity regarding the prism. Some students saw no changes to the appearance of the newsprint while others were able to angle the prism in such a way that the letters appeared to stretch and bend as they moved the prism over the newsprint. The determining characteristics identified by the students were the materials had to be clear, thick, and curved in order to magnify objects. This then led the students to the conclusion that the light is bending (refracting) as it passes through the material allowing the newsprint to be magnified. In discussing as a group following the lesson we identified a convex lens as meeting all of these criteria and can be used in telescopes, binoculars, magnifying glasses, reading glasses, and microscopes.
This lab will be used to assess the students’ understanding of what types of materials can magnify as well as their understanding the mechanism behind why those materials are able to magnify. This lab also verifies the students’ understanding of the investigative process to answer a question scientifically. Using this information will help me determine which students may need more reinforcement of the concept and which students have mastered the concept.
I feel the lesson went well in that the students were engaged from the beginning, worked well together in their groups to form a hypothesis, test their hypothesis, collect data, and draw a conclusion based on common characteristics from their data. This investigation really relies on students’ observation skills, proper data collection, and ability to find a connection between a seemingly random group of materials. I like the fact that we stopped frequently during the investigation to share, discuss, and reflect. The students benefit from this by gaining a better understanding of the scientific process.
In reviewing the lab sheets for the lesson, many students were able to grasp the concept that clear, thick, curved materials are able to act as a convex lens in refracting light giving it the ability to magnify. This becomes important for future lessons as we use microscopes to examine cells.
Going forward I think it will be necessary to examine the properties of the prism a little more with the students since this seemed to be a point of contention with many groups. Though the prism meets the criteria of being clear, thick, and can refract light, it is not a curved surface and does not meet the standard definition of a convex lens, which is the goal of the lesson. An extension of the lesson could be to examine the properties of the prism and determine why this occurs. Ultimately it boils down to how the prism refracts the light (refractive index) and since it is not curved the light does not intersect to a focal point enabling the newsprint to appear larger. This would be a great extension question to pose for those students who have a firm grasp of the magnification concept allowing them to analyze the properties of the prism and compare with the other materials such as the hand lens or water bottle.
The structured inquiry lesson following the 5 E process provides teacher guidance coupled with student testing to answer a question scientifically. I frequently use this type of lesson format when delivering content as there is ample opportunity to supplement the lesson with various media formats allowing me to cater to the different learning styles of my students.
Sunday, March 21, 2010
Melting Icebergs Experiment
Would the planet Earth experience global flooding if the polar ice caps melted? In order to examine this question more deeply I conducted an investigation called the Melting Iceberg Experiment (Laureate, 2010). In this investigation a model is created using a block of ice, representing icebergs, floating in a bowl of water, representing the ocean. I placed the block of ice in the bowl of water and filled the bowl until it was about to overflow, then I waited for the ice to melt to see if the water would overflow.
Ultimately there was no overflow due to the melting of the ice. The only overflow noted during observation was a result of the shifting of the ice block during melting creating a disturbance in the water and causing the overflow. The reasoning is that the volume of water is the same no matter what state of matter it is in. Therefore, when the ice was floating in the water it had displaced as much water as it needed to make it float, and the melting was simply taking that volume of frozen water and changing phases to liquid water. The amount of water introduced into the system did not change, only the form of water within that system changed.
So how does this relate to the polar ice caps? To examine that we first need to determine if our model was an accurate representation of the actual system created in the natural world. In an over generalized view, the Arctic ice cap is compacted snow and ice floating in the middle of the Arctic Ocean. So it would seem that our model would represent the arctic ice cap on a very basic scale. The South Pole ice cap, however, consists of large glaciers resting atop a continental landmass. This also holds true for other areas of the world such as Greenland, Iceland, northern Canada, Alaska, the Soviet Union, and in the south the far reaches of Argentina and Chile. Should these ice covered lands melt, the runoff would add a new volume of water to the existing oceans and could then cause coastal lowlands worldwide to experience some sort of flooding.
This then begs the questions; could we create a model that represents more accurately the current state of the ice caps with some ice not originally in the water and some ice starting in the water? And, what kind of results would we get if we reversed the process? In a time of global cooling the ice sheets would then get larger turning more of the water into ice. Given the data collected and results from the investigation, would that process then cause the water of the coastline to recede? My favorite thing to tell my students when they ask questions like this is that there is only one way to find out. Let's test it.
Ultimately there was no overflow due to the melting of the ice. The only overflow noted during observation was a result of the shifting of the ice block during melting creating a disturbance in the water and causing the overflow. The reasoning is that the volume of water is the same no matter what state of matter it is in. Therefore, when the ice was floating in the water it had displaced as much water as it needed to make it float, and the melting was simply taking that volume of frozen water and changing phases to liquid water. The amount of water introduced into the system did not change, only the form of water within that system changed.
So how does this relate to the polar ice caps? To examine that we first need to determine if our model was an accurate representation of the actual system created in the natural world. In an over generalized view, the Arctic ice cap is compacted snow and ice floating in the middle of the Arctic Ocean. So it would seem that our model would represent the arctic ice cap on a very basic scale. The South Pole ice cap, however, consists of large glaciers resting atop a continental landmass. This also holds true for other areas of the world such as Greenland, Iceland, northern Canada, Alaska, the Soviet Union, and in the south the far reaches of Argentina and Chile. Should these ice covered lands melt, the runoff would add a new volume of water to the existing oceans and could then cause coastal lowlands worldwide to experience some sort of flooding.
This then begs the questions; could we create a model that represents more accurately the current state of the ice caps with some ice not originally in the water and some ice starting in the water? And, what kind of results would we get if we reversed the process? In a time of global cooling the ice sheets would then get larger turning more of the water into ice. Given the data collected and results from the investigation, would that process then cause the water of the coastline to recede? My favorite thing to tell my students when they ask questions like this is that there is only one way to find out. Let's test it.
References
Laureate Education, Inc. 2010. Melting Icebergs Experiment. Baltimore: Author.
Sunday, March 14, 2010
The 5 E's and Me
I have used the 5 E template for planning science lessons for the past three years, and I believe it has really forced me to be more creative when approaching content. The model provides opportunities to deliver hands-on inquiry based lessons by first engaging the students and drawing their interest to the topic before allowing them to manipulate materials and make observations of their own. I like the fact that the students have an opportunity to explore a concept and make discoveries on their own prior to discussion or reading a selection of text. This really provides them with a context to apply the new vocabulary or concept and will make more of a concrete connection aiding in retention levels. This type of model also works well with students who are more visual or kinesthetic learners as it plays into their learning style.
The curriculum that we use in our county outlines the 5 E's and provides activities and lessons in that format. The STEM lesson I most recently outlined involved the students creating a "roller coaster" using a 2 meter piece of foam pipe insulation tubing and rolling a marble through it to calculate the speed of the marble. The students were required to put a loop in the coaster and determine the minimum speed the marble had to travel in order to complete the loop. I was first introduced to this lesson in a workshop I attended a couple of years ago and have adapted it to use in my classroom with several variations along the way. The difficult part of implementing this lesson is time as it may take two or even three class periods to complete, but the understanding and practical knowledge the students take away from the lesson is well worth the time.
The curriculum that we use in our county outlines the 5 E's and provides activities and lessons in that format. The STEM lesson I most recently outlined involved the students creating a "roller coaster" using a 2 meter piece of foam pipe insulation tubing and rolling a marble through it to calculate the speed of the marble. The students were required to put a loop in the coaster and determine the minimum speed the marble had to travel in order to complete the loop. I was first introduced to this lesson in a workshop I attended a couple of years ago and have adapted it to use in my classroom with several variations along the way. The difficult part of implementing this lesson is time as it may take two or even three class periods to complete, but the understanding and practical knowledge the students take away from the lesson is well worth the time.
Monday, March 1, 2010
Hello and thanks for checking out We're Talking Science!
I just want to start off by saying I'm an addict. I have been addicted to science, both learning and teaching, for as long as I can remember. The rush of planning experiments and learning new things with the students just keeps me coming back for more. I know I'm not the only one out there who feels this way.
What is it about teaching science that gets you hooked?
What is it about teaching science that gets you hooked?
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