Author: Sandy Van Natta
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This module provides participants with activities which can be used to help demonstrate to their students the difference between observations and inferences. Participants are asked to make observations of what appears to be a burning candle. In reality, they are observing a burning nut placed on an apple cylinder. When all the observations are listed, a discussion is lead to separate actual observations from inferences made. Next participants observe the appearance and behavior of two balls which are similar in appearance but very different in composition. Observations and inferences are made relating to the two balls.
The presenter will want to engage the participants in an initial discussion of the importance of observations in science. The discussion may lead to the expression of the difficulty the participants have in getting their students to make accurate observations. Tell the participants that you are going to do an activity in front of the class and ask the participants to make as many observations as they can. Light the apple "candle". (Avoid using the word candle in front of the group.) Have a volunteer record all the observations. Blow out the "candle", allow it to cool for a few seconds, and then eat the "candle" in front of the group. You should receive a few surprised statements from members of the group. Participants may add to their list of observations at this time!
Assessment: The evaluation is informal. Listen to the participants' observations and comments and try to encourage all members of group to participate.
Divide the participants into small groups of 2 or 3. Ask each group to evaluate the list on the board based on the last event – eating the "candle".
Assessment: Monitor the groups' discussions. Ask them to decide if all statements listed on the board were truly observations. Ask them if they made any assumptions not actually based upon their direct observations.
Involve the entire group in a discussion of observations and inferences. Ask the participants to define both terms. A definition for observations should include that observations are made using the senses. Ask participants about the role tools have played in extending our senses. You can distinguish between qualitative observations which are descriptive in nature and quantitative observations which are numerical. Once tools have been included in the discussion, encourage participants to think about the role technology has played in the development of tools and how this relates to the advancement of science overall.
Discuss value judgments that students might make and confuse with observations. Statements such as something is pretty or yucky are not true observations.
Assessment: Monitor the discussion. Ask participants to give examples from their own teaching experiences listing an inference that can be drawn from observations. For example: If a plant always grows toward the light in a window, you can infer that it needs the light for growth.
Give each small group of teachers a set of Happy/Sad balls. Ask them to make a list of observations based on both the appearance of the balls and the behavior of the balls when bounced. Participants should mass the balls, measure the height of their bounce, roll the balls, etc. After completing their list of observations, ask participants to make inferences concerning the balls based upon their observations. Observations may include the color, size, mass, and texture of the balls. Inferences may relate to the composition or the density of the balls or whether the balls are solid or hollow.
Assessment: Monitor the discussion and make sure all participants are involved. Encourage the participants to make comments and suggestions that might add to or improve this activity. During the discussion, have participants share examples of how they teach observations and inferences in their own classrooms.
Using ideas from the class discussion, write a brief lesson plan template that addresses grade level content and indicators that teaches the concepts of observations and inferences. See the Lesson Implementation Plan.
Teachers often note that their students are unable to draw conclusions and support them with the observations made during experimentation. Observations can be descriptive and qualitative in nature, or involve the use of measurement, and be quantitative in nature. However, students often make assumptions based on prior knowledge and prejudices and list these assumptions as observations. This can lead students into drawing faulty conclusions. Students often make value judgments and consider these to be observations too. This activity is designed to help the participants guide their students into making the distinction between observations and inferences and learn that true observations are needed to make reasonable inferences.
NSES Content Standard A: Science as Inquiry: As a result of their activities in grades 5-8, all students should develop
NSES PROFESSIONAL DEVELOPMENT STANDARD A: Professional development for teachers of science requires learning essential science content through the perspectives and methods of inquiry. Science learning experiences for teachers must:
Allow at least 20 minutes for the Engagement activity and 30 minutes for the Elaboration activity
Making the Candle: Push the cork borer or plastic tubing through the largest portion of the apple (or potato) flesh to make the cylinder shaped "candle" body. Dip the apple cylinder in lemon juice or Fruit Fresh to avoid discoloration. Cut several 2.5 cm slivers from a nut to make the wicks. Push a sliver into the top of the apple cylinder. Light the sliver only long enough to char the "wick". Making an extra backup candle is a good idea.
Preparing for the Demonstration: Light a second wick to determine how long it will burn. This will give you an idea of how long you can allow your candle to burn during your demonstration. Practice what you are going to say in front of the class. Avoid using the word candle.
Notify participants to bring their curriculum guide or textbook to the meeting to facilitate the development or implementation of a plan.
No special safety precautions are needed.
Have each group of participants suggest an additional activity which could be used in their classrooms which could be used to teach the differences between observations and inferences.
Give the participants a single frame of a picture from a comic strip. Ask them to list all the observations they can make from the picture. Next ask the participants to make inferences from their list of observations.
In the engagement activity, most participants will mistakenly decide that they are watching a candle burn. They will then make incorrect observations such as the candle is melting or made of wax. This exercise should emphasize the importance of only recording things that can be directly observed. Inferences need to be based on accurate observations, not preconceived notions.
The Happy and Sad balls are very similar in size and appearance. However, the Happy ball is made of the polymer, neoprene, and the Sad ball is made from polynorbornene. Neoprene is very elastic and bounces quite well. Diving wet suits are made from neoprene. The polynorbornene, in contrast, is a good shock absorber but a poor bouncer. Polynorbornene can be used in automobile tires and to line ballistic containers used by bomb squads to absorb a significant amount of energy. After examining and manipulating the two balls, participants can easily infer that the two balls are solid but not made of the same material. They may also infer that the balls have different densities. (Note, if they mass the balls, and compute the volume of the balls using the formula V=4/3 π r3, density can be computed. Density would then become an observation rather than an inference.)
Other simple activities can be used which allow for more numerical observations. A simple example would be measuring the increase in temperature of containers of soil and water placed in direct sunlight or under a heat lamp. The participants can make inferences about the ability of the soil and water to absorb heat.
Seat everyone so that they can see the demonstration and make sure every person participates in the discussions. Classroom implementation would also include grouping with diversity in mind.
None available for this module.
None available for this module.