HELP! EDDY CURRENTS

[deleted-137292]

I am doing a Science Experiment about putting a neodymium magnet through copper, aluminium, brass and PVC pipes and recorded the times for each - also repeated 20 times for each pipes - it was only suppose to be 10 but my teacher to do more trials. I have finished all the things that I need to do for my experiment and at the part of analyzing the data. So I was planning to put the data into a scatter plot but it looks kinda wrong and I don't know what to do. HELP!.
Do I need to calculate how strong the magnetic field is? and if how? IM SO CONFUSED! with this experiment. HELP! PLEASE! I need it before monday. PLEASE! HELP!

[theborg]

Geodude11,
Welcome to science buddies and thank you for the question. Sounds like an interesting experiment. Can you provide more detail? What do ypu mean "putting the magnets through the pipes" and the time recorded is the time for them to do what exactly? Also what is the current x and y axis of your plot?

[deleted-137292]

This is my method and it should answer your questions.

1. Play with the magnet and the copper pipe to get a feel for the force of the magnet. Make sure you know how to use the stopwatch.
2. Hold the copper pipe vertically. Hold the pipe near the top and have the volunteer hold the pipe near the bottom so that the pipe doesn't shake.
3. Hold the magnet at the top of the pipe. Position it at the center of the pipe's opening. Let go of the magnet and immediately start the stopwatch. Time how long it takes for the magnet to fall out of the tube. Record this time in your lab notebook.
4. Repeat step 3 nine additional times and record the data in your lab notebook.
5. Repeat steps 2–4 with the PVC pipe. Do you see a difference in the times? Were you able to see the magnet floating down the tube?
6. Plot the data that you collected on a scatter plot. Label the x-axis Tube and the y-axis Falling Time. List the resistivity values of each material on the scatter plot.

[deleted-93346]

Sorry for the delay -- just noticed 2nd question.

For the plots,
1) make an empty plot. Along the horizontal (X) axis, place tic marks at equal intervals as convenient, maybe 2 cm apart. Label each tic with one of your materials, such as PVC.

2) Look at your time data. Find the largest falling time for all the times for all the materials. Round this number up to a convenient number, for example if your largest number was 1.78 sec, you might choose 2.00 sec. Mark out 10 evenly spaced tic marks going up the Y axis, these will mark the time values from 0 at the bottom of the axis (where the X-axis intersects the Y-axis) to the top tic which will represent your convenient upper bound (2.00 if that was your choice). Then assign increasing numbers spaced at, with our sample case values, 2.00/10= 0.200 to the Y tics from 0 to your max (2 say).

3) Now plot the data for the material that looks like it had the shortest times (guess if it's not obvious) over the first X-axis tic. Put the name of the material, whatever it is, maybe PVC, below that X-axis tic mark. The times will all be greater than 0 of course, and less than 2.00, because of the way you chose the upper tic value. Thus all the time values will fit. To plot times that are fraction of the vertical tic-mark intervals, estimate where they would fall on the Y-axis, as if it were a ruler. So if you had a value of 0.30 seconds, and tic marks at 0.20 and 0.40 seconds, you would measure the distance from 0 to a spot half way between the 0.20 and 0.40 tics. Put a marker, like a dot or small circle or triangle, that is that far up above the appropriate horizontal tic (labelled PVC in our sample case). Keep doing this until all the PVC times are plotted. Where symbols fall on each other, spread them out a bit horizontally, while keeping them as close to vertically above the tic marks as you can.

4) Plot the data that looked like it had the next shortest times over the next available horizontal tic mark, an label the tick mark with the material. This will produce a vertical stack of symbol over that tic mark, separated from the data for the first material by the spacing between the X-axis tics. (TIP: if you choose different symbols for each material, or different colors, then a little unintended horizontal overlap won't matter when interpreting the scatter plot.)

5) Continue doing this for each material.

6) Label the stack for each material with the resistivity somewhere (below the name on the bottom axis, for example, or near the middle of the stack of points for the relevant material if there is adequate horizontal spacing between the columns).

7) Be sure the horizontal and vertical tic marks are clearly labelled. Label the whole axis with a name, such as "time to fall 1 meter in seconds" (use the actual length of your tubes). Date the plot and put your name somewhere. Make a box with the title of the whole plot in it if there is room somewhere.

This will be much faster to do if you have access to and the skill to use a suitable program such as Excel or Numbers on a computer somewhere.

[deleted-137292]

I don't understand how to do this with excel? and especially the tic part? im such an amateur with this

[deleted-93346]

Since you are not familiar with programs like Excel, just forget about them. The procedure I tried to describe will work with just a piece of paper, a ruler, and a pencil. Here is another option, an interactive web-based tutorial program that teaches about graphs while creating them:

http://nces.ed.gov/nceskids/createagraph/default.aspx

Maybe that will help.

"Tic" marks are little bumps on an axis of a chart that show exactly where a value lies.

Suppose we have an axis like this:
---------------------------------------------------------------

We now add numbers to the axis
---------------------------------------------------------------
...............1................2................3..................4....................5.................6
please pretend the periods in the above line are white space, this text editor won't allow blank spaces


Now we add "tics" to show exactly where the numbers are on the axis

---------+---------+---------+---------+---------+---------+-
...............1................2................3..................4....................5.................6

You may find it convenient to start with ruled paper ("graph paper"). This URL has
a PDF file with suitable rulimgs for your needs:

http://mathbits.com/MathBits/StudentRes ... ageOne.pdf

Good luck. Maybe things will be clearer in the morning.

[deleted-137292]

THANK YOU VERY MUCH! Okay, last question. What should the title of my graph would be? because I can't of anything appropriate

[deleted-93346]

"Drop Times for a Strong Magnet through Cylinders of Various Materials"