SAVRUK: Cognitive conflict with Learning cycle

SSME 512 Methods of Science and Mathematics Teaching II

Final Exam

Name: Nilgün

Target Concept: Select a target concept to be taught.

Misconception: Select a specific misconception related to the target concept.

Task: Design an instruction to handle the selected misconception and teach the target concept by using the instructional methods covered in SSME 512. You should use at least two of the following instructional methods.

· Learning cycle

· Cognitive conflict

· Modeling instruction

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Grade Level: 10^thGrade / Unit: Electricity / Chapter: Electric charges

Topic: Properties of electric charges

Objective: Students discover that matters can be charged by gaining and loosing electrons.

Misconceptions:

· The only charge of charged object is that it was charged.

· A neutral object has any charge.

Instructional Method: Cognitive conflict + Learning cycle

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Steps which will be followed during lecture:

a) Introduction to new unit. (ELICIT)

In this part I will give an introduction to the electricity unit and talk about the previous knowledge of students related to electricity. For example I will talk about notr atom and how can an atom charged. I could also use questions below:

ü What do we know about electricity, electric charges?

ü Where do we use them in daily life?

b) Showing a video and talk about it. (ENGAGE)

In order to attract students’ attention I will show a video which related to the static electricity. In the video a woman goes to petrol station. She wears jersey and she jostles car’s chair most of times with her jersey. After that she touches petrol pump and the pump catch fire at this moment.

After watching this video, I will discuss the reasons of the situation in the video. I will use mostly the why type questions and make students think & speak. The questions written below:

ü Why do you think the petrol pump catch fire when the woman approaches it?

ü Woman wears jersey, is there a relationship between this jersey and catching wire? How?

c) Cognitive Conflict Part:

Main Questions:

· Which characteristics does an object have for that it is charged?

· Which characteristics does an object have for that it is neutral?

Other Questions:

· Are there only negative charges in a negative charged particle?

· Are there only positive charges in a positive charged particle?

· Are there any charges in neutral objects?

Remembering previous knowledge: Positive charges cannot move because positive charge means proton in the atom. On the other hand, negative ones can move.

Anomalous Data

1. Collecting data and discussing with friends:

· Here, students make a small experiment to see the truth on their own by following the steps given.

Students’ thought style: ‘Positively charged electroscope’s leaves become closer when we approached the negatively charged rub near to electroscope’s knob because positive charges move from leaves to knob because of the attraction force. Then, electroscope’s leaves come closer because of the same reason. Leaves became far again because maybe the charges in rob neutralize in some amount because of our body and positive charges go to leaves again.’

· After this explanation of students, I ask ‘why?’ questions below and again remembered the previous knowledge pointed above. At the final, I give the scientific explanation.

ü Rub a straw and then load the electroscope by induction. Next, when you draw near the same straw, the leaves begin by falling down. WHY?

ü Bring the straw nearer to the plate. The leaves then diverge. WHY?

My explanation after all discussions in class:

In charging by induction with a negative straw, the electroscope becomes positive. (figure. 9) The negative straw will attract positive charges on the plate and repel more negative charges toward the leaves more it is near. Therefore, the leaves falling down (fig. 12) because they are less positive; the leaves in close contact (fig. 13) when they are neutral and then the leaves repelling again (fig. 14) when they become negative.

Result: So charged objects have not only charges that is the same as that they have. Only thing is that the number of same kind of charge that they have is over. Neutral objects have both negative and positive charges in same number.Otherwise, if that was true, when the negative charged particle bring closer to positive charged electroscope, firstly, leaves of the electroscope gets closer to each other than,slowly they closed,consequently it can not be charged negatively because there was no any contact between electrification object and electroscope.

d) Make groups and distribute the other activity sheets to groups. Doing activities and controlling the students while they do demos. (EXPLORE)

After discussing video, I will distribute the activity sheets to students and give them enough time for doing the activities and answer the questions in these sheets and finding the answers related to their hypothesis about the video. There are three different activities and groups could be formed by 3 to 5 students. While students do the demos, I will control and help them about their faults. While they explore activities I will encourage students to explore their hypothesis too. In this process, I will help them by asking aided questions not by directly saying the answer.

In activity 1: I will ask why the balloon sticks on the wall; why the PVC pipe attracts the small bits of paper and why the straw attracts the book’s paper.

In activity 2: I will ask why the PVC pipe attracts the water.

In activity 3: I will ask why the Plexiglas attracts the small bits of paper and with which type of charge the Plexiglas charged.

e) Distribute evaluation sheets about group performance.

After all groups finish their activities I will distribute evaluation sheets and ask them to answer in one minute. It involves 1 minute at the end of activity where the students write down answers on a ‘1 minute paper’ to a few questions as feedback to the instructor. The questions are as following:

ü Did everyone in the group participate?

ü Did the group stay on task?

ü Did an individual dominate the group?

ü What was the most important idea you learned today?

ü What is one idea you are still confused about?

f) Let students to explain what they have done. (EXPLAIN)

After collecting evaluation sheets, I will let students to explain what they have done in each activity. Every group will choose a talker for their group and these students will explain groups’ ideas. I will ask them evidence for their explanations.

g) Explain briefly the students’ results.

After students finish their explanations, I will briefly explain their results and if there will a wrong thing in their explanations I will correct them. In other words, I will provide a general explanation based on students’ observations and findings.

For activity 1: I will say charges of the balloon deforms by influence atoms of the ceiling.
Once more attracted charges are nearer so attraction is the strongest force. According to the action and the reaction principle the force exerted by the ceiling on the balloon is opposite to that the balloon exerts on the ceiling. I will also say different materials have different amounts of attraction for electrons. When two objects rub against each other it is likely that one will steal electrons from the other. If you rub a balloon against your hair, the balloon will steal electrons from your hair. This leaves your hair positively charged and the balloon negatively charged. Your hair will be attracted to the surface of the balloon because opposite charges attract. You will also notice that your hair stands up even if the balloon is not near them. This is because each hair is positively charged and is repelled by the hair next to it. The forces between similarly charged hairs cause them to try and get as far away from each other as possible.

Students should also notice that after rubbing the balloon on their hair, they can get the side of their balloon that touched their hair to stick to other things like a wall or ceiling. This happens because the negative charge on the balloon will force some of the electrons in the wall to move to the other side of their atoms. This leaves the surface of the wall closest to the balloon positively charged. The positive surface of the wall and the negative surface of the balloon will attract each other. If the air is very dry, the balloon should stick for many hours, possibly even days! Students should remember that the moisture in the air can steal charges from the balloon, so on humid days this may not work at all.

For the attraction of straw part of activity 1: I will say that the rubbing electrifies the straw by leaving it an excess of negative charges. Admit that:

like charges repel each other
opposite charges attract
these attraction or repulsion forces are more intense on those that are closer.

By approaching a neutral object (it contains an equal quantity of charge of both signs) the straw attracts the positive charges that become closer and push away the negatives ones. The global force effect will therefore be an attraction.

For activity 2: I will say the straw is made of molecules that have electrons floating around them. Electrons have negative charge. When the straw charged with hair, it collects electrons from the individual strands of hair to itself. The molecules in the water stream are neutral. When tester brings the straw close to the water stream, electrons that are closer to the straw are being repelled away. Therefore, the molecules that are closer to the straw become positive and away from the straw, there is more negative charge.

I will also say the molecule of water is a combination of two atoms of hydrogen and one atom of oxygen. In this coupling the three atoms are not aligned. It results that the molecule behaves electrically as two opposite charges remaining very close that is called dipole. In the absence of any electrical induction the orientation of these dipoles is at random and globally no charges distinguish. It changes when one approaches the straw since it attracts positive charges and repels the others: the dipoles orient, so that the attraction results.

For activity 3: I will say materials are attracted to the Plexiglas after it is rubbed. This is because the wool deposits extra electrons on the sheet, giving it an overall negative charge. The electrons in the tiny objects are then repelled by the sheet and move to the bottom of the pieces leaving the positively charged protons near the sheet. The objects moved up toward the Plexiglas because the protons are attracted to the negatively charged Plexiglas.

h) Give the concept effectively. Talk about like and unlike examples. Transferring the concept other situations with the help of brain storming.

(ELOBORATE & EXTEND)

I will again talk about the concept and give effective explanations again. After giving concept, I will talk about two similar examples with the help of the slides in order to provide a new activity in which students find opportunity of using new knowledge and encourage them to use scientific explanations in different situations.

I will talk about charging:

By transferring electrons from one place to another. We can do this by physical contact, (substances are rubbed together or simply touched.)
Or we can redistribute the charge on an object simply by putting a charged object near it—this is called induction.
While running a comb through our hair on a dry day, what causes the hair repels one another?

Then I will say we are all familiar with the electrical effects produced by friction. We can stroke a cat's fur and hear the crackle of sparks that are produced, or comb our hair in front of a mirror in a dark room and see as well as hear the sparks. We can scuff our shoes across a rug and feel a tingle as we reach for the doorknob.

After that I will mention charging by induction as, if you bring a charged object near a conducting surface, you will cause electrons to move in the surface material even though there is no physical contact. Consider the two insulated metal spheres, A and B, in the Figure.

(A) They touch each other, so in effect they form a single non-charged conductor.

(B) When a negatively charged rod is brought near A, electrons in the metal, being free to move, are repelled as far as possible until their mutual repulsion is big enough to balance the influence of the rod. Charge is redistributed.

(D) They will each be equal and oppositely charged. This is charging by induction. The charged rod has never touched them, and it retains the same charge it had initially.

I will mention about Thunderstorms:

Charging by induction occurs during thunderstorms.

The negatively charged bottoms of clouds induce a positive charge on the surface of the Earth.

Benjamin Franklin was the first to demonstrate this when his famous kite-flying experiment proved that lightning is an electrical phenomenon.

Lightning is an electrical discharge between a cloud and the oppositely charged ground or between oppositely charged parts of clouds.

i) Make a quiz.

At the end of the course I will distribute a quiz in order to evaluate students’ understanding of new knowledge.

- Quiz:

1) Give one example to electrify with impact, friction and interference.

2) In the activity of bending water with a straw, what was the reason that the pvc pipe draw the running water?

REFERENCES:

Hewitt, P. G. (2006). Conceptual Physics (10th ed.). San Francisco: Pearson Addison Wesley.

Kalyoncu, C., Tütüncü, A., Değirmenci, A., Çakmak, Y., & Bektaş, E. (2008). Ortaöğretim Fizik 9 Ders Kitabı. Istanbul: MEB.

Tsokos, K. A. (2008). Physics for IB Diploma (Fifth ed.). Cambridge: Cambridge University Press.

For activities:

ü Mausian , M., (n.d ) , Attraction and repulsion of light objets , Retrieved December 20 , 2012,from University of Nantes, Electrostatic Experiment web site: http ://www.sciences.univ-nantes.fr/sites/michel_maussion/statelec/PagesEngl/01Attrac.html

ü Mausian , M., (n.d ), Trickle of water , Retrieved December 20 , 2012,from University of Nantes, Electrostatic Experiment web site: http://www.sciences.univ-nantes.fr/sites/michel_maussion/statelec/PagesEngl/03Water.html

ü Ben Franklin's Secret Message (2006), Retrieved from http://www.physicscentral.com/experiment/physicsquest/past/upload/pq06-Extension1.pdf

ü Mausian , M., (n.d ), Charging and discharging by Contact , Retrieved December 20 , 2012,from University of Nantes, Electrostatic Experiment web site: http ://www.sciences.univ-nantes.fr/sites/michel_maussion/statelec/PagesEngl/05Conta.html

Activity – 1

Attraction of the Balloon and Attraction of the Straw

a) Attraction of the Balloon

Materials: A balloon, a paper handkerchief, a wall.

Procedure:

ü Inflate a balloon.

ü Rub the top of the balloon with a paper handkerchief.

ü Push it delicately to the ceiling.

Questions:

1) What did you observe?

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

2) What is the reason?

b-1) Attraction of the straw

Materials: A straw, a paper handkerchief, small bits of paper.

Procedure:

ü Rub a straw with a paper handkerchief.

ü Draw it near small bits of paper or aluminum foil lying on an insulating table.

Questions:

3) What did you observe?

4) What is the reason?

b-2) Attraction of the straw

Try same things with a book this time.

Rub a straw with a paper handkerchief and draw it near to a book’s paper.

Questions:

5) What did you observe?

6) What is the reason?

Activity – 2

Bending water with a straw

      Materials: A straw, a plastic cup that has a small hole at the bottom of it, water.

      Procedure:

     1.    One of the tester hold the cup.

     2.    Other tester fill the cup with water.

     3.    Charge the straw with hair.

     4.    Bring the straw close to the stream of water.

Questions:

1) What did you observe?

2) What is the reason?

Activity -3

SAVRUK

4 Haziran 2013 Salı

Cognitive conflict with Learning cycle

Dancing fleas:

Materials: Plexiglas sheet, a piece of wool, paper squares.

Procedure:

- Put paper squares on the table.

- Put Plexiglas on paper squares.

- Rub the top of the Plexiglas.

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