New toys - old concepts - The Leslie Cube

A Leslie cube is a small hollow metal box with different painted sides. One is bare metal, the others are matt black, gloss black and gloss white.
The cube is filled with water and then heated until it boils.
Using an infrared thermometer we look at the temperatures  of the different surfaces. Each is a different temperature as seen in the pictures.

With a burner under the cube the water is heated until it is boiling. and the temperature of each surface is measured.
The bare metal surface came out as 49.3C

The Matt black surface came out as 97.9C

The smooth black surface as 95.9C

And the white surface as 97.0C

There is a difference. The bare metal was cooler by far. Now why might that be?

Maths GCSE Retake in Nov

Its time to start panicking. Do a set of exam papers ( calc and non-calc every week. Compare your answer to the marking scheme. The answer is not good enough all the working is required. Look at their working out in the marking scheme. How many marks would you get. Read the examiners report for each exam. It helps you know where others went wrong and perhaps how to avoid the pifallls.

Many schools don't use a Maths book. The revision guides are ok but a real Maths book with lots of questions are so much better. There are many to choose from amazon.


These books can help but any are good
Try to attempt one question from each section or exercise of the book each time you revise. It should take a little over two hours - almost the time of an exam paper.
Ideally you need to do this once or twice a week if you want a good grade.

The difference in a grade is about 2-3 hours of revision, so if you want the grade then you must do the learning. Maths is about practice as well as doing the learning how to do it.
Generally know how to do a sum is not the same as doing it.

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.

Good books for science GCSE

 I am often asked which books I recommend for GCSE Science. These books are very visual but have a large amount of content. These books are written for all syllabuses ( AQA, Edexcel and OCR) and thus cover all the different GCSE's in three books. These books are for Single, double and triple science. They also cover most of the material for the 21st Century syllabus as well.
Each Chapter is well laid out with images and a good deal of well displayed facts. There is also a substantial amount of text as an explanation. This is much better than some of the normal students books which do not give enough material. These books provide some background material which is otherwise

missing from their school books.
At the end of each chapter there is a summary with some missing word to complete and some questions. At the end of each topic there are some past  paper questions and others from all boards.
These represent good books at a good price to cover all the different boards syllabus.
Each book has plenty of images both pictures and graphics to show or explain each different situation.
Hemel Private Tuition

Private Tutoring Boosts grades

If you want to improve your grades then a Private Tutor seems a good idea. An hour with a private tutor and your grades shoot up from a U to and A*.

Unfortunately this is not the case.

The tutor may know the yllabus and the work and may be able to explain it differently to you than your teacher did, which will help you to understand what you didn't learn in class.. The tutor has only you and you to full concentration. Your grade might go up a bit, but to go up more then you need to do some work as well.

You now have a better understanding of the subject but now you need to learn this work.

How do you learn this stuff.

1. Make notes of what the tutor says. The tutor may make notes but you also need some.
2. Read through these notes a few times.
3. Read the notes again another day.
4. Do some practice questions.
5. Get these questions marked with someone telling you waht you did wrong.
6. On another day do these questions again just after you have re-read your notes.
7. Try some more questions.

With a Private Tutor for a few weeks and doing all of the above, you grades will soar.

The Learning still has to be done, but guided learning makes things easier.

EM Spectra

What is Light? How are the other EM Spectra different?

They are not is the simple answer. From Gamma rays to radio waves the EM spectra is just the same, its only that we perceive them differently and need different ways of detecting the waves.

Lets look at an example.
We see light in all its different colours. Each different colour is a different wavelength. Lets look at Infra red. if I shine an infra red beam at you, you don't see it simply because your eyes don't detect infrared radiation. If I direct a camera (that has a wider capture range than your eye) at an infrared beam then I can "see" it - simply because the camera detects the light and changes its wavelength into something you can see.
You Tube video of a looking a Sky remote

So know you can see IR light then UV is the same. Moving further along the spectrum then we need different types of detectors to detect the radiation. Our hands work well as detectors on the lower end of the infrared and for more frequencies we need more and different detectors.

The detectors change but the nature of the waves does not change.