Applied Science - Science and Math (2A) Pre Lab
 OBJECTIVES: Exploring perception. Comparing and contrasting optical illusions. VOCABULARY: circle diameter height line measure optical illusion perception tall wide MATERIALS: worksheet Internet rulers Students observe optical illusions.
 BACKGROUND: Science is a subject that teaches many principles required throughout your student's life.  It helps develop critical thinking skills that can be used in many situations.  Students should begin to learn that the world can be seen many different ways and that there is often more than one explanation.  There is not always a correct answer in science because many times the answer changes with new information.  There can also be more than one answer depending on the tools used to derive the answer.      Mathematics is more than just memorizing addition or division.  Math is a tool for humans to compare and contrast objects quantitatively.  Scientists require math as a tool to help them record and compare their data.  Math and science work together to help us understand the world.     Optical illusions can dramatize why scientists must measure and record their observations, repeatedly.  Initial conclusions can be proven inaccurate or incorrect when the situation is fully analyzed.  The verification of an initial conclusion should be part of how human beings can use critical thinking as a way of living.  PROCEDURE: Perception is how one sees an object or event.  Students may have heard  "your eyes can play tricks on you," but not understand what it means.  In this lesson, students should look at objects and make a judgement about that object.  They will find when they measure the object, the answer their eyes may have seen was incorrect.  There are 3 pictures:  (1) hat, (2) lines, and (3) circles.  Ask students the following questions when you show them the pictures.    Hat:  Is the hat wider or taller?  After the class answers (take a hand count), ask students if they can explain how they made their decision.  Hopefully one of the students will suggest measuring the hat.  Instruct several of the students to measure the width and height.  They will find out that they are the same.  Discuss reasons why this happened.  This is an example of our eyes "seeing" the tall hat and disregarding the width.    Lines:  Which of these lines is longer - line AB or line CD?  Take a hand count of students and then measure each line.  They will find out they are the same.  This is an optical illusion caused by the arrows guiding our eyes.    Circles:  Which center circle is the largest?  Again take a poll of the students, and then have them measure the diameter of the circles in the center of each illusion.  They  will measure the circles as the same size.  Make sure that the students know what a diameter is, and have them measure the diameters of both circles to compare.  Your eyes are comparing it to the larger circle.  The circle on sheet B looks larger because it is surrounded by smaller circles.    Sometimes what appears to be true is not!  Do not believe all you see. Sometimes you have to question what you are really seeing as opposed to what you think you are seeing.  There are many books on optical illusions which you may want to consult.  You may want to check the following websites that have some illusions.