The psychology of magic

and brain structure.

There is a limit to the amount of processing power that can be pact into the brain. Although the brain can not physically pack any more cells into a given volume it can increase its processing power by clever algorithms. These few lessons should reveal how magicians use these algorithms to their advantage. For example, when looking at a static image for a while we tend to not notice certain detail. This is critical in allowing the brain to focus on other tasks and not to be distracted by events it considers to be non-essential. This is called neural adaptation and will be covered later. Even when we are focusing on an event we can still miss critical detail. Our brain is not that good at picking up detail and the lessons to follow will demonstrate this through phenomena such as Change blindness, inattentional blindness, covert and overt misdirection

Magicians simply rely and manipulate the inbuilt mechanisms provided by evolution to allow the brain to function in a busy and dangerous environment.

1) Discuss the psychology of magic. Terms such as Change blindness, inattentional blindness, covert and overt misdirection. Point our how magicians use change blindness and the significance to the accuracy of eyewitness accounts. Discuss an experiment conducted which shows the susceptibility of people to change blindness. View a magic trick that demonstrates attention blindness.

2) Discuss saccadic eye movement. Have students participate in a brief activity which demonstrates saccadic eye movement. You will need one small mirror between two students. Outline the physiology of the eye.

3) Conduct an eye dissection and discuss the specialised cells of the eye, nerve structure and transmission of signals.

4) Introduce the phenomenon of the afterimage and neural adaptation. Discuss how parts of the brain that process different sensations may act to alter what is perceived (multisensory illusions). Outline the specialised function and structure of a nerve cell and discuss how nerve cells communicate with each other over small distances called synapses.

5) Using a sheep's brain conduct a dissection and identify the different parts and their function. Students should be able to give some explanation as to how the different parts work together to make sense of the environment and react to it. Discuss how the brain manipulates images to give the illusion or perception of depth.
Discuss how the brain works to create illusions how it is capable of processing information and predicting outcomes or filling in the gaps to create reality.

6) Discuss neuroscience as a human endeavour. Discuss how neuroscience is using magicians to better understand cognition using modern imaging techniques such as MRI. Outline, in basic terms, how an MRI image is created. The link should provide all the necessary information needed. Students can research how MRI has significantly increased detection of tumors and treatment of injuries.

Eye dissection.

Sheep's brain dissection

Rubric for brain dissection

1) Start the lesson by performing a demonstration on the magic of chemistry using the red cloth trick and the disappearing water trick. This is an excellent starter to the introduction of redox and acids/base reactions and indicators. After the performance, discuss the different aspects of this trick, such as:
i) How water can be broken down into its component elements, oxygen and hydrogen by an electrical current. Demonstrate this concept.
ii) How some chemical reactions involve the transfer of electrons and are known as redox reactions, as is the case with the first reaction of the trick, involving the battery,
2 I^- ==> I₂ + 2e-
and some are acid/base reactions involving the transfer of protons.
iii) How starch turns blue in the presence of iodine (I₂) and how one can be used to indicate the presence of the other.
iii) How indicators are chemicals that change colour in different pH solutions, such as thymolphthalein and congo red.
Describe pH as a measure of how many free hydrogen ions are present in the solution. Use universal indicator to demonstrate colour change over a range of pHs pointing out that the more red the colour the higher the hydrogen ion concentration and the more blue the colour the lower the hydrogen ion concentration. Discuss how acids are chemicals that release hydrogen ions in solution while bases are chemicals that can hydrogen ions from the solution.
2) Follow on with a discussion of chemical reactions and chemical equations.
3) Perform the Exploding-can trick. Discuss collision theory and the need for molecules to collide with each other with enough force in order for a reaction to occur. Demonstrate the magic wine bottle trick and follow on from the chemistry of the previous lesson. After revealing the chemicals allow students time to investigate the individual reactions to this trick. Class set of solutions should be made available for students to analyse in microscale.
4) Demonstrate the Storm in a tea cup as another redox reaction involving electron giving and electron taking while energy release is quite spectacular. A Flexicam is ideal to project this reaction on the big screen.
Demonstrate the Genie in the bottle trick and the Green Dragon trick as exothermic, heat releasing, reactions whose rate of reaction is increased by a catalyst. Discuss the role of catalysts in speeding up the rate of reaction but is itself not been used up. See if students can perfect the genie in a bottle trick so that it simulates an escaping genie.
5) Demonstrate the rags to riches demonstration. Discuss alloys, how the addition of other elements to a metal can change its properties, steel is a good example. Allow students to select a trick that has not been performed, such as the rising water trick or the light a candle trick and offer an explanation using science for both. .
6) Students can investigate a simple water trick to see how it is achieved. Students design and conduct the investigations in an appropriate scientific manner and share their results, only in written form, paying close attention to the variables and controls of their investigation and the appropriate use of tables and graphs, where needed. Students should be able to describe dependent and independent variables with a number of examples. One way to carry out the simple water trick is to demonstrate it to the class at the start of the lesson. Allow students to form their own hypotheses as to how this trick works and to carry out experiments to cllect data that will support or refute their hypothesis.

Another very interesting magic trick is performed with hydrogels. Discuss the uses of such plastics in items such as nappies. When on the subject of plastics the never ending string trick can be demonstrated by the teacher.
The periodic table can be introduced as a chemical neighborhood where position of an element is crucial to the way it will behave. Briefly discuss the atomic structure and how elements in the same group have similar properties, due to the number of electrons in their outer shell, using group 1 and group 18 elements as examples.

Introduce students to the magic of precipitation reactions and the Law of Conservation of Mass.

Precipitation reactions can also be introduced as a way to magically produce coloured powder from the mixing of two clear solutions. Further, students should be able to name , write the chemical formula of the precipitate and write a balanced chemical equation of the reaction.

When writing the chemical formula of a precipitate this link may be very handy for students to visualise the process.

Making an indicator

Water trick

Investigation of the:
- candle smoke trick
- rising water trick
- fire works in milk.
- simple water trick
- hydrogels(*demo)

1) Demonstrate the falling magnet trick. Introduce Faraday's and Lenz's laws and discuss how a moving magnet in a pipe can induce a magnetic field that opposes its movement. Allow students time to investigate questions such as:

What is the effect of the thickness of pipe to the induced magnetic field?

Does aluminium work just as well as copper pipes of similar thickness?

Discuss how a generator works in a similar way with changing magnetic fields that induce a current in copper wires.

2) Using a Van De Graaff generator discuss static electricity and perform the magic octopus and Mexican tissues tricks. Allow students time to explore answers to questions on the worksheet.

3-5) Introduce electromagnets and levitation. Build an electromagnet and investigate the relationship between coils of wire and strength of magnetic force. Cover dependent and independent variables.

Forces of repulsion created by powerful magnets are a source of excitement when they are used to defy gravity. A number of commercial toys can be used to demonstrate this. Soldering irons can be used to develop an electrical circuit that can be used in a magic trick. An electromagnet is always a good start to electric circuits.

Investigation of the relationship of the number of coils in an electromagnet vs magnetic field strength.

Building a simple electric motor.

Build a levitating pencil.

Test -dependent, independent variables, line of best fit.

Falling magnet investigation. Lenz's Law

Manipulation of light and illusions

What you will need for this section of magic, is a number of mirrors, ranging from flat, concave and convex, polarised filters and light boxes. A laser pointer will also come in handy as will prisms with which to bend light and create a rainbow effect.
1) Discuss the composition of white light as being made up of many different frequencies of light. Students should be familiar with terms such as refraction and reflection as well as total internal reflection. Discuss the application of total internal reflection in the telecommunication industry. Demonstrate total internal reflection using a laser pointer and a 2 litre empty coke bottle.

2) Discuss, in simple terms, how flat, concave and convex mirrors reflect light to form images. Use the pig demonstration to show the formation of a virtual image. Students should be familiar with real and virtual images and be able to distinguish one from the other. Demonstrate the formation of real and virtual images using concave and convex mirrors.

3) Using a light box students should be able to draw line diagrams of images formed from concave and convex mirrors.

4-5) Students should be allowed to apply their knowledge of mirrors and behaviour of light in describing a number of magic tricks or illusions. Discuss how flat mirrors can be used to create illusions. If time permits, allow students to attempt to replicate some of these illusions using flat mirrors.

6) Discuss the wave nature of light and the definition of polarised light. Allow discussion on how sunglasses work. Students should be allowed to experiment with different types of polarised filters.

Light boxes.

Building a kaleidoscope.

Optional and if time permits

Students should be given time to perfect a magic show with at least 8 tricks ranging from brain illusions, chemistry, electricity and mirror images. Students are encouraged to seek at least 4 new tricks that have not been demonstrated in class. A written explanation of the science behind each trick should be included. Group work, of no more than four students per group, is encouraged, however individual reports are required. A multiple choice test of 24 questions, 3 questions per trick, testing the science behind each trick can be written by the group. This test will be taken by each member of the group and questions from each group may be included in the overall class test.

** all magic tricks involving fire should be cleared with the teacher and must only be conducted with the teacher lighting the matches. Chemical explosions are not to be performed by students.

Exam revision

Solutions to exam revision