Classroom Activities
Differentiating between qualitative and quantitative observations
Students will learn the difference between a qualitative and a quantitative observation. Students will be given about three minutes to make as many observations of the classroom as they can. After they have written down their observations, I will have them call out their observations one at a time. I will put them into two different sections on the overhead. Observations with numbers will be in one column and descriptive observations will be in the other column. After there are several examples in each column, I will ask them if they can tell the difference between the two types of observations. Eventually they understand the root words quality and quantity and they then have an understanding of the difference between qualitative and quantitative observations. Both have an important place in science skills.
Activity: There are actually two relatively short activities involved here. The first is one in which students will be given a piece of hard candy and asked to use all of their senses to describe it. This is strictly a lesson in qualitative observations. They are to be as descriptive as possible. We will discuss commercials in which a lot of similes and metaphors are used in order to describe a product. Each student is to write a descriptive paragraph of the candy without using the word "candy" and they are strongly discouraged from using words like "good" and "hard." This exercise lets them know right away that writing will be a regular part of their science class and it also gives me a good idea of where their general writing skills are.
The second activity will include qualitative and quantitative observations. Students will work in groups of four for this activity. They will be given a candle, a ruler, a piece of string, clay to stand the candle up, matches, and a balance. The classroom clock can serve as a timer. They are given approximately ten minutes to make as many observations as possible. I give them no directions on how to use the available materials. After ten minutes, I tell students they will have a quiz on their candle, but will be allowed to use their observation notes while they take it. Very rarely do students get even half of the questions correct because they have not learned how to use everything available to them and fail to see what it means to make detailed, thorough observations. The quizzes are not counted, but after seeing the types of questions asked, they begin to understand what careful observation means. (Copy of sample quiz in appendix.)
Wrap-up discussion: I will ask students to describe situations where careful observations are necessary. Because of the prevalence of forensic-based TV shows, I expect there to be some discussion of crime scene analysis, which will lead us into our unit on detective fiction.
Drawing inferences from observations
Students will have several different situations shown as drawings on the overhead. They will first have to make observations about the drawings and then make inferences about the drawings. We will discuss the difference between the two. Inferences are based on your observations. They may not be correct and need further observation and/or experimentation to be proven correct.
Activity: The first part of the lesson is a demonstration by the teacher. The students will be shown a can of coke and a can of diet coke and a tank of water. The students will be asked to predict what will happen when the two cans are dropped into the water. There are only three possibilities: Both will sink, both will float, or one will sink and one will float. Students will discuss their choice and why they made that choice. After discussion, the cans will be put into the water and students will see that the Diet Coke floats and the Coke sinks. Using inductive reasoning, we could also put in Diet Pepsi and Pepsi, Diet Dr. Pepper and Dr. Pepper to see that the results are the same. Next, they must come up with inferences as to why the cans behave that way. After discussions about the amount of caffeine, sugar, carbonation, etc., we discuss how we could further experiment to find out which of the inferences are correct. We would then discuss the kinds of quantitative observations to make to find out the correct answer.
The second part of this lesson is called "dancing raisins" and once again involves making observations and inferences about the behavior of the raisins.
At the end of both activities, we will discuss what is necessary to prove that the inferences they have made are correct.
Students will listen to an exercise in inferencing to discuss the logic of making inferences. I will be reading the short story "The Nine Mile Walk" by Harry Kemelman because it is an exercise in the possibilities involved in making inferences. After reading and discussing the path taken in connecting a chain of events, I will have students make up scenarios of their own in which multiple inferences are possible. They will be given a period of ten to fifteen minutes to think of a scenario on their own with possible inferences, then they will share their scenarios with a partner. If time allows, students will be allowed to share with the whole class. This exercise will help them understand the backward thinking that sometimes comes with solving a crime.
Learning to listen
Students will listen to very short mystery stories to try to pick up clues by listening. I will be using the Encyclopedia Brown Mystery Collection by Donald Sobol as an introduction to mystery stories. These stories are written on a third to fifth grade reading level and so are probably well below the ability of many of my students. However, for content area classes, this is appropriate, so that students can concentrate on specific tasks during the reading, rather than on vocabulary. I have chosen this collection of mystery stories because they are only five to six pages long and can be read aloud in a relatively short amount of time. There are only a few clues that students will need to listen for to try to solve the mystery. The students will listen as I read aloud and be asked to write down information as I read. I will first have them predict what the story might be about based on the title. I will then read and ask them to describe the mystery or problem when they hear about it. When I assess that all students at least have an accurate sense of the problem at issue, I will then have them begin writing down clues as they hear them. Before the mystery is actually solved, I will have students discuss in small groups of three to four the clues they have heard and develop theories for a possible solution. After a few minutes of small group discussion, I will have a class discussion about the possible solution. I will then read the end of the story and have students think of the clues they may have missed and why they missed them. I will probably read three to four of these stories to get the students comfortable with this type of story and to continue practicing their listening skills and practicing making inferences.
Using Detective Fiction to practice problem solving
Students will begin reading the short story "The Speckled Band" by Arthur Conan Doyle to work on their problem solving skills.
Activity: I will assign the short story, "The Speckled Band" by Arthur Conan Doyle to be read in sections by the students. This short story, of course, stars the legendary detective Sherlock Holmes. Because some of the language and style of writing will be difficult for my students, I will review many of the unfamiliar words by providing them with a glossary specifically for this story. I will also discuss many of the words with them prior to reading. I will be dividing the story into three sections to be read on three different days. The first section will include enough pages for students to find out what the mystery is and to pick up a few clues to begin making inferences and formulating a theory. We will read the first couple of pages together to make sure the students are comfortable with the style of writing. To go with the story, they will be given a graphic organizer, one that will include the problem, the suspects, possible motives, and evidence (graphic organizer included in appendix). On the first day, the students will read the first eight pages, up to the part where Helen describes the condition of her sister's body. Students will then have enough information to think of suspects and motives. On the second day, students will get the next fourteen pages of the story. This part of the text will give them enough information to begin to formulate some inferences and theories about what may have happened to the woman. After small group discussions, they will continue to write down clues and revise their inferences and/or theories, based on clues or evidence they may have learned from each other. On the third day, students' graphic organizers should be complete with their final theory. We will have a class discussion about their theories and the evidence they have used to come to the conclusion that they have. We will read the third and final part of the story and find out how close students came to solving the mystery. Discussion will include what they might have missed in reading the story that might have helped them to solve the mystery. We will also talk about theories that were not logical and why they were not.
Students will gather "evidence" in the classroom to solve a crime.
Activity: Students will come into a "crime scene" in the classroom where they will have to make observations and gather evidence to try to solve the crime. The crime scene will actually be spread across "centers" in the classroom where students will have the opportunity to analyze fingerprints, compare thread samples, soil samples, and hair samples, and possibly test fluids found at the scene. One of my personal classroom items will be discovered missing, an apparent robbery, and students will be given information about possible suspects to try to figure out who did it. I will arrange ahead of time to have samples from volunteer "suspect" adults in my building.
I have decided for this unit to stay true to the Holmes era and use only the tools that would have been available at that time. Students will have magnifying glasses, samples to compare their own samples with and possibly some chemicals to test some of the fluids found. Fingerprinting had become available as a crime solving tool in the late 1800's. Holmes was knowledgeable about the various soil types in his region and also had familiarity with different types of cloth and material. Holmes was also an accomplished chemist, so students may be conducting some basic chemistry testing of fluids from the scene. For this part of the unit, I will not be looking at blood as evidence, but will be including that aspect of forensic work later in the year, during the genetics unit.
Compare/contrast tools used in crime solving today with tools and methods used in Holmes' time period.
As a tool for comparison between Holmes era crime solving and the current methodology for crime solving, I will be preparing a "murder bag" as used by Scotland Yard in the first half of the twentieth century. The tools included in the brown leather bag brought by detectives to crime scenes were rubber gloves, handcuffs, bottles for samples, screwdriver, magnifying glass, and plaster for making casts of footprints. I will ask students to describe what each of the items may have been used for and then make comparisons between that "murder bag" and a bag that may be used at today's crime scenes. What would still be useful to detectives today and what would be available now that was not available then? Students will create a Venn diagram to compare and contrast the methods of detection used in the early twentieth century with the methods used today. After discussing their diagrams and completing one on the board, we will watch a short video clip of Holmes at a crime scene and then the CSI crew at a crime scene. Is there a disadvantage to relying too much on current technology? Do the old fashioned skills of observation begin to deteriorate with the advent of lasers and computers? Are there differences in the kinds of clues for which they are searching? Students will be given the opportunity to answer those questions in groups, and then in a whole class discussion.
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