Engage:

Teacher plays a clip from Star Wars, where the Millennium Falcon is being drawn in by the Death Star’s “retractor beam”

Ask students to draw a diagram of the what is happening, using arrows to represent forces that are being applied to the spaceship

Now I want everyone to represent the power or magnitude of the force by drawing more powerful forces as longer lines, and weaker forces as shorter lines.

Suppose we are on our spaceship, headed to mars, and we are passing by some large object, a moon or asteroid or something.

If necessary, ask the students to sketch out the same thing in their notes

(Draw a line from Spaceship to destination)

(Draw a line from spaceship to nearby planet)

Approx. Time__15__mins

Critical questions that will establish prior knowledge and create a need to know

What direction is the retractor beam coming from? What direction does HanSolo make his rockets fire? Directly in front, or from above or at an angle?

So in the movie, which force was stronger?

What happens to objects, as they are near large objects, such as planets?

What does the Earth do to us?

So if we are traveling in this direction, and we are getting gravity from this direction what would happen to the spaceship?

Just by guessing, which way do you think we should fire the rockets, to keep from getting sucked in to the planet?

Why did you draw it the direction you did?

So we know, what direction, but do we know how much power to use to keep from getting sucked in?

Expected Student

Responses/Misconceptions

Students will draw a rough diagram that should look like:

Some students will have the arrows at different lengths, others might show magnitude by arrow length.

The retractor beam/deathstar.

Students should now draw a picture like the one above, showing unequal lengths.

It makes gravity.

It attracts us because of gravity.

The planet will pull it?

It will continue going straight?

It will go straight, but curve toward the planet.

The students should choose a direction roughly opposite to the gravity.

It is opposite the gravity/ we need to make the gravity zero/ equalize the gravity.

No.

Explore:

Learning Experience(s)

Hand out or ask students to get out their graph paper.

We are going to learn how forces can be combined in space, but we are going to learn this for any type of magnitude that also involves direction. This is called a vector. (write vector on board)

Suppose we have 2 vectors, such as the ones that show the forces on the spaceship. When the two vectors act together, they form a resultant. (write resultant on board) (lable v1, v2, and R on diagram.

Hand out the worksheet.

The students will work on the resultant worksheet in pairs or groups of 4.

Pass out rulers, and protractors?

Approx. Time 20-30 minutes

Critical questions that will allow you to decide whether students understand or are able to carry out the assigned task (formative)

So, we don’t know the exact angle, or the exact magnitude of the force. Now we will try to find out these exact details.

Expected Student

Responses/Misconceptions

.

The students should have no problem drawing the lines. They will have trouble determining the length of the resultant. Some will use the ruler and measure it. Encourage the use of the ruler, for a rough answer.

Explain:

Learning Experience(s)

Make sure all worksheets are completed

Choose a handful of students to show the results on the board. Have them stay up to explain how they did it. (One or two people per question set, on the worksheet)

Approx. Time__10___mins

Critical questions that will allow you to help students clarify their understanding and introduce information related to concepts to be learned

So, do the resultant vectors make sense to you, if you think of them as forces? Think if one rocket is pushing you one-way, and gravity is pushing you another.

What makes them look unconvincing?

How would you draw the resultants?

What made you draw them this way?

So, who was able to find the length of the resultants?

Does it make sense that we started with 2 vectors of the same magnitude, yet the resultant was less than the sum of the two.

Does it make sense that one vector is on the positive side, the other is on the negative side, yet the resultant is still positive?

Expected Student

Responses/Misconceptions

Students should see that they are about right. If they don’t think they are right, ask why they look wrong.

Students may say things about how the larger vector should overpower the small one, or how they even each other out.

Students could have measured, or used the distance formula, or Pythagorean theorem.

.

They are opposite in direction? Or

No it doesn’t.

Students should see that the vector on the positive X is longer than the one on the negative X.

Extend / Elaborate:

The teacher should know, what makes something representable by a vector. It must have a magnitude and direction.

Approx. Time__5___mins

Before we finish for the day, what were we using vectors to represent?

Do all vectors have to be forces though? What else can we use vectors to represent.

What is common between all of these? What must you know about them before representing them as a vector?

Retractor beam, rocket force, force in general.

Remind students about spaceship movement, if they have forgotten.

Expect any kind of measurements. Speed, length, weight, temperature.

They must have a magnitude/size/length, and a direction.

.

Evaluate:

Approx. Time_5 mins or as homework.

I want all of you to think up 3 scenarios in which you could use vectors to represent something. It could be an action, or something standing still. Write the scenarios down. Go ahead and estimate or imagine some of the nubmers involved in these situations. Draw them on graph paper if you want. (This can be done at the end of class as a homework assignment)