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.

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.

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,

Exam Techniques

PANIC. Before the exam. This is Good. This might motivate good revision.
If you have revised well then you are well prepared.

• Check what exam you have the next day.
• Revise for that exam.
• Prepare everything you need to take to the exam.
• Get a good nights sleep before the exam. Go to bed a bit earlier and don't do any revision 1/2 hr before going to sleep.
• Have a good breakfast. If you don't normally then this is a good time to start.
• Read the front of the exam paper thoroughly. This reminds you of how many questions to do in each part.
• Read each question through to the end BEFORE you answer the question to make sure that you put the right answer in each part and do not get ahead of yourself.
•  In some papers the harder and more marks questions are at the end, These are often longer and take more time, so plan out your time - how much time for each question. 
• A wrist watch is excellent here for timing. You won't be allowed your phone. A watch with a second hand helps with the timing. If it helps take it off and put it on the desk in front of you.
• Answer all the questions you can. If you can't do a question then leave it and come back to it.
• Make sure all the keywords for this topic/section are used
• If you are running out of time then bullet point the facts
• For an essay question plan it first. Jot down a few notes. You can then refer to these in case you forget one as you write the essay.
• Come back to the questions you can't do. 
• Put down some answer. It might just be right. 
• If you have no idea than put down any relevant keywords or phrases.
• In some papers (like Maths) working from the back to the front can help. The harder/longer questions are at the back of the paper and you get these over when you are freshest and the easier ones come later.
• When your finish go back and check your answers. Read the question again and check you have answered what was asked.
• Remember ....  RTFQ Read the F..... Question
• RYA Read you answer. I often feel I am the first person to read what you have written
• Sometimes it right to go with your gut feeling answer to a question. It is often the right choice.

Last minute revision - what can you do to boost a grade

Different subjects require different techniques, but here are some ideas.

• Get some cards and write down facts about a topic 
• Important - One card per topic
• Write down keywords and their definitions write the definition on the back. It helps you learn it.
• Learn these facts- read them out loud. It is better with an audience, such as the dog or cat
• Now give the cards to someone and get them to test you. This is the only way it works.
• Get some past papers and have a go at doing them under pretend exam conditions - you don't have to do the whole paper just a few questions. 
• Look at the mark scheme. See what the examiners want.
• Check the facts of your answer. If you don't know enough then get some more cards and write down more facts and start the process again learning these facts.
• Run out of papers to do - then try some questions on the same topic from another exam board. Remember that that examiners will never give you the same questions as in a previous paper but often a variation on a theme.

Using Lego to Teach - Basic Levers

The basic Lego lever. A few brick and a pivot is all that is required. The pivot needs to allow the bar to more freely.

A homemade lego weight using a lego rock filled with 1p's. This gives enough weight (load) to be noticed using a finger as the effort.









 A first class lever. Press on the yellow flat brick.










A second class lever such as a wheel barrow. It is necessary to lift under the flat yellow plate.










A third class lever such a fishing rod or tweezers for a pair of third class levers. It is again necessary to lift under the yellow plate.

Using Lego to teach - Lever Arm Balance

Lego can often be used to create many instruments that are expensive to buy or who will be used so little that the cost cannot really be justified. That's where creating an object like this Lever Arm balance - that really works is well worth it.

Lego do make one of these in one of their educational sets, but I just made mine from a collection of Lego that I had.

The lever is an example of a first class lever. The car wheel is used as the counterbalance. The balance can accurately weigh up to about 200g in this configuration. If another wheel is used then far more. In the 0-200g range the balance is accurate and quite sturdy. The scale was made from a piece of paper and calibrated using a series of known weights.