data loggers (1 Viewer)

whiz

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can someone explain to me how data loggers work - in relation to the syllabus dot point: perform a 1st hand investigaiton to determine initial and final velocity, range, max height etc?
 

Fosweb

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You obviously didnt do a prac like this then? (I'd be complaining to the science faculty for the coming years sake, as there are so many physics/chem pracs that need dataloggers now...)

Datalogger: its like a little computer boxy-thing, that you can either use independant of a computer, or plugged into a computer. You attach a sensor to it, which get information and either stores this or sends it to the computer.

In relation to this dot point, we didnt use a datalogger - we used a ball-pitcher (you know the blue things with two wheels), and fired the balls across the oval (most fun i have ever had in physics...), measured range/time, had initial velocity set on the machine, then worked out the rest...

For a prac with a datalogger: we did one where we dropped a magnet through a pipe, with sensors attached in different places on the pipe (must be plastic to avoid lenz's law kicking in). The sensors picked up a voltage, and sent this to the computer. The computer works out how fast the magnet was going. We moved the sensors, and dropped the magnet from different heights in the pipe. Things to note: the voltage is always higher in the second sensor than in the first, as the magnet has fallen further to get to this one, and is thus travelling faster. The voltage's go like this:

<sub>------</sub>/<sup>--</sup>\<sub>\<sub>--</sub>/</sub>/<sup>------</sup>

as they enter the sensor one way, and leave the opposite way.
 
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Originally posted by Fosweb

For a prac with a datalogger: we did one where we dropped a magnet through a pipe, with sensors attached in different places on the pipe (must be plastic to avoid lenz's law kicking in). The sensors picked up a voltage, and sent this to the computer. The computer works out how fast the magnet was going. We moved the sensors, and dropped the magnet from different heights in the pipe. Things to note: the voltage is always higher in the second sensor than in the first, as the magnet has fallen further to get to this one, and is thus travelling faster. The voltage's go like this:

<sub>------</sub>/<sup>--</sup>\<sub>\<sub>--</sub>/</sub>/<sup>------</sup>

as they enter the sensor one way, and leave the opposite way.
Which DP was this for?
 

helper

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A datalogger is an electronic device used to take measurements. They have the advantages of taking multiple measurements and cann be more accurate.


For projectile motion. A photogate is placed in front of your projectile launcher, when the projectile goes through the gate, the light is stopped, and the time light is stopped for, and measurement of the size of the projectile enables the initial velocity to be calculated.

A pressure pad is placed where the projectile is to land. This detects the projectile landing. The time of flight can be determined by calculating the difference in time from photogate to pressure pad.

The distance from the pressure pad to the photogate is normally measured manually.

As for the other points final velocity, range, maximum height etc they are normally calculated from the points measured.

Other adaptations:

Second photogate at end to calculate final velocity, as for inital velocity

Motion sensors can be used to calculate range and maximum height but neither is recomended.

A sample of practiles using pasco dataloggers can be found in their manual

ftp://ftp.pasco.com/manuals/English/ME/ME-6810/012-05088D/012-05088D.pdf



Other possibility is to use a digital camera as a datalogger. A video of the projectile path is taken. This is imported into the computer and software is then used to determine each of the points mentioned.
Example stepthrough
http://www.lsw.com/videopoint/vp/tips/demo/started.html

You should check with your teacher about the skills questions that more likely to come up from the skills datapoints which relate to dataloggers

11.3 choose equipment or resources by:a) identifying and/or setting up the most appropriate equipment or combination of equipment needed to undertake the investigation
c) identifying technology that would be used during investigation determining its suitability and effectiveness for its potential role in the procedure or investigation

12.2 gather first-hand information by:a) using appropriate data collection techniques, employing appropriate technologies, including data loggers and sensors

e) recommend the use of an appropriate technology or strategy for data collection or information gathering that will assist efficient future analysis

12.4 process information to:a) assess the accuracy of any measurements and calculations and the relative importance of the data and information gathered
b) identify and apply appropriate mathematical formulae and concepts
c) best illustrate trends and patterns by selecting and using appropriate methods, including computer assisted analysis
 

Fosweb

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I have to say, that our projectile prac was so much cooler...
(We didn't have pressure pads and the like.)
 

helper

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Cooler yes, but not going to get you the marks in the HSC if they were asking about dataloggers.

Lots of cool pracs in projectiles like firework rockets and water rockets.
 

Fosweb

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Well - you also have to remember that not every school has access to dataloggers (cost reasons?), so the question won't say "You did this with a datalogger - tell us how".
It should also give a way out for people who havent had access to a datalogger.
 

helper

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Fosweb that is not considered an excuse anymore, and the BOS of studies have notified all schools they must do specified pracs, just like a compulsory text in english.

All goverment schools were given a few thousand dollars to buy the equipment.

It is more likely to be orientated towards the skills but at some stage they will ask about a datalogging experiment and in physics this prac is compulsory.

This year probably not but when it comes up cost will not get a school off.
 

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