Monday 29 July 2013

Lego NXT Calculating force of gravity

I made a simple lego contraption to measure the force due to gravity.
The device consists of a lego retort stand with a switch at the top and a switch at the bottom.
We drop a lego tyre via a quick release mechanism. The tyre is connected from top to bottom by a piece of string that does nor impede the fall but guides the wheel down onto the switch at the bottom.
When we release the wheel at the top the timer starts and when the switch at the bottom is hit then the timer stops. Knowing the distance and the time then the NXT can calculate the force of gravity.

Thursday 18 July 2013

Lego NXT Science Bot as a Dynamics Trolly

When I was at school and when I taught in schools a few years ago dynamics trolleys with ticker tape timers were often used to teach the fundamentals of mechanics and newtons laws. My son at 18 and having just survived A level and GCSE physics had never seen such a trolley so with the help of Lego and an NXT brick here is an updated version. I have used this with my students to perform similar experiments without using the ticker tape timer. The NXT acts as a data logger and then uploads the information to the PC where the files are displayed as graphs in Excel.
Building Instructions for the Science Bot.
Program for the Science Bot

When the Science Bot is ready to go, the program removes the old data file and then records the number of 1/16 rotations (this corresponds to 1cm distance traveled. The distance and the time is recorded. This information is then sent to the PC as a comma separated file and then graphed in Excel.


The time is taken every 0.02 seconds which gives plenty of data per second.

As assembled the science bot has uses an acceleration sensor (not used in this program) and one of the old RCX mindstorms rotation Sensors.
The yellow box on the side is an old rpm sensor, which works independently of the mindstorms.

Friday 12 July 2013

Summer Holidays - time to loose all those skills

The summer holidays come and for many students this is 6 weeks when they can relax, recover, go on holiday and forget about school and school work. This is so true because when the Autumn terms starts in September 3-6 months of recent work and skills will be lost and much of this work will have to be re-learnt and done again.

Although the summer holidays are good fun for students in year 10 going on to year 11 and those moving from AS to A2 this can be crucial. Some parents keep me on as a tutor though out the summer holiday to ensure that their children do not fall behind and loose too much knowledge.

If you can't do this then try to spend a day a week looking at each of your subjects, I would suggest 30 mins to 1 hr a week on each subject. spending just and hour a day, keeps the facts and skills in your head to that all that hard work does not melt away,

Tension Protractor

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