SUBJECT: FORCE AND KINETICS AT 8th LEVEL

the lesson plan for 80mn so two lecture hours.

GRADE: 8. class

UNIT: Force and Kinetics

OBJECTIVE: Students will be able to infer that the buoyant force of swum matter is equal to weight of it. (1)

Students will be able to design a system about balance of buoyant force and weight. (2)

THEORITICAL FRAMEWORK: We use team interview model in cooperative learning model and classroom discussion model. First of all, team interview is applied and then the discussion part is applied.

First objective is comprehension level of cognitive domain because it requires the acquirement of information and inference a general statement. The second objective is creation level of cognitive domain. Students should design their own experiments and they should explain what is happened in your own statement.

In this lesson plan, there are two assessment parts, one of which is creation an experiment during the lesson and the other one is puzzle at the end of lesson. The former is formative assessment because teacher does not give point and it is used for to understand whether students acquire the knowledge or not. The later is summative and so teacher gives a point and does at the end of the lesson.

For prerequisite knowledge, we accept that students know the definition of force and weight, additionally; they know that how a material swims and why it swims and they know how the forces add to find net force.

Required materials; balance, two large bowls, two different liquid such as tea, juices, glycerin, and two different materials such as wood and both of them swim in the liquid; one of which is a stone, the other is iron but its inside is blank.

INTRODUCTION:

Showing some pictures and asking appropriate questions;

In which of them can people easily swim? Why?

Which of them is heavier? Stone, sail or ship? Why does stone sink while ship can swim?

This part is for taking attention and creating discrepant event. At the end of the lecture students get the right information about these questions.

Teacher prepared a comics in cardboard and paste on the board. In comics, there are many characters and dialogs which include definition of force, weight and previous topic of liquid lift force, and especially why some materials swim and others sink. Many students go to near board and activation of characters. It can be a game. In order to increase understanding, teacher may repeat and explain detail by exampling a simple question about finding net force and writing the formula of density. If students do not remember the previous knowledge, they cannot do the experiment so with the help of comics, they remember.

(if has the same direction, they are summed, however, if they are opposite direction, they are subtracted. If the result is zero, this means that the system is balance and there will be no chancing.) (Oooo! You know a lot of things!) (How can ı know more than one force?) (Do you know the meaning of force?) (Imm no! Do you know?) (Yes, of course. It causes motion or prevent the motion.)

(No. it is the ratio of mass per volume. Do you remember?) (Sure, ı am hardworking student. İf the density is bigger than liquid, it sink but the opposite condition, it swims. Do you know the density?) (Hıım. İt is crowded as the bus fulls of human)))) (Aa yes, maybe! Either I can remember or ı cannot!) (:S do you also know this? ) (Do ı explain to you why some materials sink in the liquid while the other swim?)

While the reading comics, teacher asks to students these questions and if there is a need, s/he gives more detail.

LECTURE:

Assign students to team: students are divided heterogeneously in the teams.

Instruct team member: Teacher gives materials to students and wants to prepare a mechanism. A bowl, liquid and a material are chosen by one student, other triple materials are also chosen by other students and two students will be a group. They prepare their systems and observe differences between them. After that, they put two of materials in the same liquid. At the end of the observation, they try to answer the previous questions together with using liquid density, material weight in air and in liquid. They especially set up a relation between lift forces to wealth. At the beginning of the experiment, teacher gives a worksheet (1).The aim of this part that student discover the relation of weight to buoyant force

How the matter can swim?

Aim: To find the answer of why some matters can swim.

Material: Two bowls

Liquid (tea and juice)

Wood, chalk

Balance

Draw your observation;

Answer the question with the help of your observation

What is the difference swimming in the sea and in the pool?

Which of them is heaviest? (stone, sail, ship)

Why does stone sink while ship can swim?

(worksheet 1)

Conduct interviews:

Students talk about the experiment and the questions. They try to answer it. However, they need more information about the subject so teacher joins the interview and gives some hints. These hints can be;

They remember that density= mass/ volume, there are more than one force acting on material and these forces cause only one net force in previous activity. In these processes, teachers may guide them with giving some information and attend their discussion, as explain in the fifth step.

Students set up this hypothesis that if a matter can stay without touching floor, it should be in balance and the balance means Fnet=0. Only if the lift force and the wealth equal each other, net force can be zero. Students try to infer this knowledge in discussion with partners and teachers. Teacher attends the discussion in each group and may be giving more information.

When the discussion part continues, students have a problem about the defining of lift force. Teacher explains the lift force as the force of liquid through the up direction and giving the formulas as Fk= Vb×ds . If the densities of liquids are the same, volume of matter is important and the volume correlates with density and mass of matter.

This information is given at each group. If there is no necessity, teacher does not give this knowledge and students establish their hypothesis alone.

Continue to interviews:

At the end of first experiment, in order to learn how effective and understandable lecture is, teacher wants students to make the second experiment and complete the worksheet. The purpose of the experiment to test the students set up the right hypothesis, that is, students understand the relation of weight and buoyant force. With the help of second experiment students take more information and they note more knowledge about the subject, the notes are used for discussion part.

In the experiment, students have water, glycerin, alcohol and milk, iron cube, plastic cube, glass cube, balance and dynamometer. (worksheet2)

Comparing the weight and buoyant force?

Aim; to observe the weight differences between in the air and in the liquid

Materials: Water, glycerin, alcohol and milk

Iron cube, plastic cube, glass cube

Balance and dynamometer

Complete the table: please write the weight of matter in the table

In air

In water

In milk

In alcohol

In glycerin

Iron cube

Plastic cube

Glass cube

Write your hypothesis;

(worksheet 2)

Teacher gives additional information to students in this step. This information is;

Force means an effect on the matter and it can change the direction, shape or velocity. It may provide a kinetic or prevent the kinetics. When defining force teacher uses a students to explain what he/she means on the students. He/she take the students hand to top to explain change the shape or turn him to back to tell the chancing direction and so on.

Net force can be express with the help of three students. One is stay in the middle and one of them pulls to one hand and the other pull the other hand the opposite direction. And the student in the middle goes one direction in which force is bigger. This shows that if there was opposite force, they subtract to find net force. In contrast, two students pull the same direction and the students in middle goes rapidly the direction. It shows that if forces are the same direction they are added.

Balance is also express with the help of students. If two students pull the middle one with the same force, the middle students continue to stay at the same position and this means that net force is equal when the system at balance.

Mass and volume can be defined as puzzle says and teacher reminds some 3-dimensional objects’ volume on the board.

Teacher can give the wealth formulas to support the definition. G=m×g

In order to remind density, teacher also gives the formulas.

Buoyant force helps us to carry heavy materials easier. Each liquid has different lift force and it changes according to liquid density. Giving the formulas again and showing the relation with volume in the liquid and the liquid density.

Swim occurs if and only if, lift force and wealth equals each other because the matter reaches balance on the liquid. Otherwise, it must sink.

Read the materials and prepare the questions:

Students take notes during the lesson and the materials in these notes. And the questions are assed at the beginning of the lesson.

Plan and cluster the questions:

We have one basic question which is why some matter can swim on the liquid, the other ones sink.

Our cluster questions are; in which of them (sea or pool) can people easily swim? And why? Which of them is heavier? Stone, sail or ship? Why does stone sink while ship can swim?

Conduct to discussion:

Teacher asks the questions again and takes answer from each group. Students set up a hypothesis and they answered the questions while making the experiments so this part is a kind of sharing knowledge. Each group states their views and the right answered are taken after the discussion.

For the second question, students answer like; ship can be swim because the inside of iron is blank, that is, mass is small while the volume is huge. Its density is small when compare to sea. However, mass of stone is huge, contrast to volume and its density is big so it sinks.

For the first question, sea and pool have different density and the density of sea is bigger than pool’s so lift force is bigger in sea and we can swim easier without sinking, which is appropriate answer came from students.

CONCLUSION:

Debrief/ summarize and review: Both discussion and cooperative learning model end with this part.

Students learn a lot of concept so in order that these concept can be acquired properly, teacher distributes a puzzle and give five minutes to be completed. After this period teacher can learn that whether the concepts are learned or not?

With this assessment, teacher can give point and he/she review the lecture.

PUZZLE

Aim; to review the concepts

Please complete the puzzle;

(VOLUME)2

(LIFMFORCEİ) (F O R C E ) 1 4

(W E I G T H)

3 5

(D E N S İ T Y) 6

(N E T F O V C E ) 7

(MÜSS) (B A L A N C E)8

(S W I M )

9

1. It is an influence which changes the direction, shape or velocity and it starts the kinetics or stops to kinetic.

2. Each matter has an area in the space

3. It is a kind of force which depend on mass and gravity

4. Liquid has an effect to matter with up direction.

5. It is distinguishing property and proportion to mass and volume

6. It is the result of adding or subtracting more than one force.

7. The constant matter quantity

8. Net force equals to zero, the continuity what it does, if there is a kinetic, it continue the kinetic, if there is no motion, again there is no motion.

9. Lift force and weight are equal each other for a matter in the liquid. What does it appear?