Using Slopeslider Applet
This assignment is designed to be given to students as an
addition to regular classroom instruction. If the class can meet in a computer lab, it can be completed there. Otherwise, students can work independently
using any computer with Internet access. (at home, in an after-school program,
or in a library).
Task 1:
This assignment must be done on the Internet. Follow the
instructions and answer all questions in complete sentences.
Go the URL: http://www.shodor.org/interactivate/activities/slopeslider
On this web page you should see a set of coordinate axes and
the graph of a line. Below the graph
you see an equation and two colored rectangles that can be moved using the
mouse.
Using your mouse move the green rectangle from left to
right.
1. What happens to
the green number in the equation as you move the green rectangle to the right?
2. What happens to
the line on the graph as you move the green rectangle to the right?
3. What are the
maximum and minimum values for the green number?
maximum _________ minimum_________
Now use the mouse to move the purple rectangle to the right.
1. Describe how the
line changes as you move the purple rectangle to the right.
2. Move the purple
rectangle until the line is horizontal. What is the value of the purple number?
3. Look at a line when the purple number is 1. Now change the purple number to –1. Describe how these two lines are different.
*4. What value of the purple number do you need to use to
make the line vertical? (You can change the maximum and minimum values by
clicking on the “Slider Settings” button.)
Now use the mouse to move the blue rectangle.
1. Describe what happens on the graph.
________________________________________________________________________
2. Where on the graph is the x coordinate
positive?
________________________________________________________________________
3. Where on the graph is the y coordinate
negative?
________________________________________________________________________
Task 2:
If you have already used the browser today please click on
the refresh button to clear the settings of the applet so that both the purple
and green numbers are set to 0.00. From this point on we will refer to the
purple number as m and the green number as b.
1. Select the box labeled Show Trace. Change the value of b
by sliding the green slider. How would you describe the lines that are drawn?
_____________________________________________________________________
2. Change the value of m by moving the purple
slider. Now click on the box labeled Clear Trace so that only one line is left.
Again change the value of b. How would you describe the lines
that are drawn?
________________________________________________________________________
3. Lines that have the same value of m are
____________________________.
4. Read the coordinates of the black dot (x1, y1) and
record them on the table below. Move the blue slider and record the new
coordinates (x1 , y2) on the table. Using this values
calculate the remaining columns on the first row of the table. Repeat this
procedure for two more pairs of points and complete rows two and three of the
table.
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x1
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y1
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x2
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y2
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y2 - y1
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x2 - x1
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(y2 - y1) / (x2 - x1 )
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5. What do you observe about the numbers on the last column?
6. Does this number either match m or b?
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