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Defining the Kilogram

Scientists are set to change the way the kilogram is defined…

Currently, it is defined by the weight of a platinum-based ingot called “Le Grand K” which is locked away in a safe in Paris.

Researchers are expected to vote to get rid of it in favour of defining a kilogram in terms of an electric current. The decision is to be made at the General Conference on Weights and Measures, in Paris.

But some scientists, such as Purdey Williams at the National Physical Laboratory in the UK, have mixed feelings about the change.

“I haven’t been on this project for too long but I feel a weird attachment to the kilogram,” he said.

“I think it is such an exciting thing and this is a really big moment. So I’m a little bit sad about [the change]. But it is an important step forward and so the new system is going to work a lot better. It is also a really exciting time, and I can’t wait for it to happen.”

Why kill off the kilogram?

Le Grand K has been at the forefront of the international system of measuring weights since 1889. There are also several close replicas.

But the master kilogram’s days are numbered. Its weight has changed over the years because it has deteriorated. The kilogram, like the pope, is infallible, so other weights have to be adjusted accordingly.

In a world where accurate measurement is now critical in many areas, such as in drug development, nanotechnology and precision engineering – those responsible for maintaining the system plan to overturn Le Grand K’s increasingly flawed rule.

How wrong is Le Grand K?

The fluctuation is about 50 parts in a billion, less than the weight of a single eyelash. But although it is tiny, the change can have important consequences. Coming in is an electrical measurement which Dr Stuart Davidson, head of mass spectrometry at NPL, says is more stable, more accurate and more egalitarian.

“We know from comparing the kilogram in Paris with all the copies of the kilogram that are all around the world that there are discrepancies between them and Le Grand K itself,” he said.

“This is not acceptable from a scientific point of view. So even though Le Grand K is fit for purpose at the moment, it won’t be in 100 years’ time.”

How does the new system work?

Electromagnets generate a force. Scrap-yards use them on cranes to lift and move large metal objects, such as old cars. The pull of the electromagnet, the force it exerts, is directly related to the amount of electrical current going through its coils. There is, therefore, a direct relationship between electricity and weight.

So, in principle, scientists can define a kilogram, or any other weight, in terms of the amount of electricity needed to counteract its force.

Here’s the tricky part

There is a quantity that relates weight to electrical current, called Planck’s constant – named after the German physicist Max Planck and denoted by the symbol h.

But h is an incredibly small number and to measure it, the research scientist Dr Bryan Kibble built a super-accurate set of scales. The Kibble balance, as it has become known, has an electromagnet that pulls down on one side of the scales and a weight – say, a kilogram – on the other.

The electrical current going through the electromagnet is increased until the two sides are perfectly balanced.

By measuring the current running through the electromagnet to incredible precision, the researchers are able to calculate h to an accuracy of 0.000001%.

This breakthrough has paved the way for Le Grand K to be deposed by “Die Kleine h“.

What are the advantages of the new system?

Every few decades, all the replica kilograms in the world have to be checked against Le Grand K. The new system, if it is adopted, will allow anyone with a Kibble balance to check their weights anytime and anywhere, according to NPL’s Dr Ian Robinson.

“It feels really good to be at this point. I feel it is the right decision. Once we’ve done this it will be stable for the foreseeable future,” he said.


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Rosenshine Principals

This is all about an interesting piece of quite old action educational research produced by Robert Stevens and Barak Rosenshine and has revised many times over.

They were trying to produce a commonality between lessons and what is required to produce “good learning”. They initially came up with 6 instructional teaching functions which I would say for most teachers who have done the job for some time would recognise without any issues. It is what you are doing every day for pretty much every lesson.

  1. Review, checking previous day’s work (and reteaching if necessary).
  2. Presenting new content/skills.
  3. Initial student practice (and check­ing for understanding).
  4. Feedback and correctives (and re-teaching if necessary).
  5. Student independent practice.
  6. Weekly and monthly reviews.


His 2010 they produced work on the ‘Principles of Instruction’ which was grounded in a range of evidence from three sources:

  1. Cognitive science research focusing on how the human brain acquires and uses new information. This provided insights into how to overcome the limitations of working memory when attempting to learn new things.
  2. Direct observation of teachers whose students made the most academic progress as measured by attainment tests. These focused on aspects such as how they presented new information and made explicit links to prior learning, how they monitored and assess the understanding of their students, how they provided opportunities for rehearsal and practice, and the types of support used to scaffold the development of understanding and retention of knowledge.
  3. Research on cognitive supports and scaffolds, such as the use of models and instructional procedures, that helped students to learn complex tasks.


Rosenshine further researched and modified the ideas to finally come up with 17 Principles of Effective Instruction (version expanding on his initial 10 principles)

  1. Begin a lesson with a short review of previous learning.
  2. Present new material in small steps with student practice after each step.
  3. Limit the amount of material students receive at one time.
  4. Give clear and detailed instructions and explanations.
  5. Ask a large number of questions and check for understanding.
  6. Provide a high level of active practice for all students.
  7. Guide students as they begin to practice.
  8. Think aloud and model steps.
  9. Provide models of worked-out problems.
  10. Ask students to explain what they have learned.
  11. Check the responses of all students.
  12. Provide systematic feedback and corrections.
  13. Use more time to provide explanations.
  14. Provide many examples.
  15. Reteach material when necessary.
  16. Prepare students for independent practice.
  17. Monitor students when they begin independent practice.


It’s also quite interesting that when you read through each one and mentally tick off those lists, we can all see that all of us use these all the time. Some teachers also look at a simplified version of just 10 of the key teaching functions as 17 is a lot of remember.

  1. Begin the lesson with a review of previous learning.
  2. Present new material in small steps.
  3. Ask a large number of questions (and to all students).
  4. Provide models and worked examples.
  5. Practise using the new material.
  6. Check for understanding frequently and correct errors.
  7. Obtain a high success rate.
  8. Provide scaffolds for difficult tasks.
  9. Independent practice.
  10. Monthly and weekly reviews.


I also think that all of us should not get in too much of a panic about ensuring that these are present in every lesson. Clearly the way it is written is to think about a sequence of lessons and different functions should come into that series of lessons.

I have produced a quick review of what a 9 lesson SOW might contain, and you can see how the 1-10 ideas apply in different ways. I think if you are following something like this a SOW should work. I also think that the key to a good SOW is to have a really good mixture of activities and styles within the unit which are key focus points: a practical, a video, a literacy activity which you really can go to town on and build understanding and context.





Key terms/ Intro / Check Prior learning

1, 2, 3, 6, 7



2, 3, 4, 5, 6, 7, 8



1,2 ,3 ,4, 5, 6, 7, 9


Recap/ Review

1, 6, 7, 9, 10



1, 2, 3, 4, 5, 6, 7, 8



1,2 ,3 ,4, 5, 6, 7, 9



1, 6, 7, 9, 10



5, 9, 7, 10



4, 6, 7, 8, 10

Expanded Ideas….

I found a really good list of expansions online for the 10 key ideas. Which may help you understand what is meant by each one if you are an NQT. I think they are very well written.

1 Begin the lesson with a review of previous learning.

Rosenshine suggests investing 5-8 minutes to review previous learning. This can be in the form of questioning techniques to check understanding and to uncover and challenge misconceptions, peer or self-marking work and correcting mistakes. This will strengthen understanding and the connections between ideas.

2 Present new material in small steps.

Presenting new information in small, bite-sized chunks increases the progress made by the students. Introducing too much at once will see progress rates fall as they can only process so much at one time. This reduction in cognitive load allows metacognition to take place (it allows them to think about how they are thinking about the task).

3 Ask a large number of questions (and to all students).

Questions are a teacher’s most powerful tool, they can highlight misconceptions, keep a lesson flowing and challenge students to think deeper into a subject. The greatest value of questioning though is that they force students to practice retrieval, this strengthens and deepens memory.

4 Provide models and worked examples.

Delivering new information to students by linking it to something or some process they are familiar with allows students to gain an understanding quicker, it also gives them deeper retention. This is especially true of more conceptual ideas.

In Science, we may explain the flow of electrons in a circuit by using the model of the water in a “lazy river”. The water being the flow of electrons, the pumps providing the voltage (power) and the people in the water providing resistance.

5 Practise using the new material.

Practice makes perfect right? Rosenshine postulates that this is true of physical, vocal and mental practice. He suggests that successful teachers allow more time for guidance, questioning and repetition of processes. Actually, in teaching, I prefer to use the phrase “Practice makes Progress”.

6 Check for understanding frequently and correct errors.

Regular asking of direct questions (rather than “does anyone have any questions?”) allows teachers to check a classes/student’s understanding and catching misconceptions, therefore informing the teacher whether any parts of the topic need reteaching.

7 Obtain a high success rate.

Teaching for mastery ensures all students in a class are ready to move on to the next stage in the topic, thus preventing students from taking misunderstanding into their future learning. From his research, Rosenshine found that a class that the optimal success rate is an 80% understanding. This shows that not only have the students learnt the material but also were challenged in doing so. Any higher and the work may not have been challenging enough and vice versa.

8 Provide scaffolds for difficult tasks.

When introducing a more difficult lesson, Rosenshine suggests employing Vygotskian scaffolding. Providing students with a framework that more easily allows them to make progress. The scaffolds can then be gradually removed as their competency grows. Examples of scaffolds can include; checklists, cue cards or writing frames. Teachers can also anticipate commonly made errors and build tools into the scaffold tasks that reduce the chances of students making the same mistakes.

9 Independent practice.

Following scaffolded tasks, students should be competent in the task and therefore can practice the task independently. This repetition of the task will promote a deeper fluency, Rosenshine called this “overlearning”.

10 Monthly and weekly reviews.

An extension of the first principle, monthly and weekly reviews of previous learning aids recall of information and processes. Also it fits into the idea of spaced learning.


Rosenshine, B. (2010). Principles of instruction; Educational practices series; Vol.:21; 2010. The International Academy of Education, 21(2010).

Rosenshine, B. (2012) Principles of Instruction: Research-Based Strategies That All Teachers Should Know. American Educator, 36(1), p12-39. Rosenshine, B. and Stevens, R. (1986) Teaching Functions. In Witrock, M.C. (Ed). Handbook of research on teaching, 3rd ed., pp376-391. New York; MacMillan.

Rosenshine, B. and Stevens, R. (1986). Teaching functions. In M. C. Wittrock (Ed.), Handbook of research on teaching (3rd ed., pp. 376-391). New York: Macmillan

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Challenge Boards

Here is a quick presentation to share letting you know about the use of “challenge boards”.

They essentially work as mini-plenary tasks or tasks at the end of the lesson. It is important that students have learning that they can apply to the task so I wouldn’t recommend use in the first 15-20 mins of the lesson. The tasks are metacognitive so use the idea of learning about learning. They are easy to create and something which is a go to for pupils who have a bit of spare time and like a challenge. You can also do some topical questions!   They can glue them in their book and work as a pair as well.

Challenge Boards



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The first room-temperature superconductor has finally been found

It’s here: Scientists have reported the discovery of the first room-temperature superconductor, after more than a century of waiting. The compound conducts electricity without resistance up to 15° C, but only under high pressure.

The discovery evokes daydreams of futuristic technologies that could reshape electronics and transportation. Superconductors transmit electricity without resistance, allowing current to flow without any energy loss. But all superconductors previously discovered must be cooled, many of them to very low temperatures, making them impractical for most uses.

Now, scientists have found the first superconductor that operates at room temperature — at least given a fairly chilly room. The material is superconducting below temperatures of about 15° Celsius, physicist Ranga Dias of the University of Rochester in New York and colleagues report October 14 in Nature. However, the new material’s superconducting superpowers appear only at extremely high pressures, limiting its practical usefulness.

Dias and colleagues formed the superconductor by squeezing carbon, hydrogen and sulfur between the tips of two diamonds and hitting the material with laser light to induce chemical reactions. At a pressure about 2.6 million times that of Earth’s atmosphere, and temperatures below about 15° C, the electrical resistance vanished.

Superconductors and magnetic fields are known to clash — strong magnetic fields inhibit superconductivity. Sure enough, when the material was placed in a magnetic field, lower temperatures were needed to make it superconducting. The team also applied an oscillating magnetic field to the material, and showed that, when the material became a superconductor, it expelled that magnetic field from its interior, another sign of superconductivity.

The scientists were not able to determine the exact composition of the material or how its atoms are arranged, making it difficult to explain how it can be superconducting at such relatively high temperatures. Future work will focus on describing the material more completely, Dias says.

When superconductivity was discovered in 1911, it was found only at temperatures close to absolute zero (−273.15° C). But since then, researchers have steadily uncovered materials that super conduct at higher temperatures. In recent years, scientists have accelerated that progress by focusing on hydrogen-rich materials at high pressure.


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Animated Science GCSE 1 to 9 Methods Summary

Animated Science 1-9 GCSE Practical Methods

This booklet of Methods is a simple reference point for the 1-9 Physics GCSE Required Practical methods.

Often questions will be based around these themes and you must learn to interpret the questions on the day as they will try and put them in unfamiliar situations.

This booklet is not designed to teach you everything in the practical’s but to be used to recap what you have already done in class. I have limited most topics to 1 or 2 pages of the bare basics.

You must be able to recall all this booklet and the ideas in it if you want to be able to answer some of the questions in your exams.

They are sure to ask about at least 2 of these topics, and most likely 4 or 5 topics in details so time spent on these topics will stand you in good stead.

Try and use this booklet as a starting point and then read more around the subject and tackle some exam questions to help you out.

Animated Science GCSE 1 to 9 Methods Summary  (PDF)

I have also included some more help on each of the Key Terms you need to know as well. It can be viewed as a PowerPoint or PDF….

Science Key Terminology in Context  (PPTX)

Science Key Terminology in Context (PDF)

GCSE 1 to 9 Summary

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Holst Planets Suite & Nocturnes – Gloucestershire Youth Orchestra 1994

This post is to celebrate a moment in time from 1994 when Gloucester Youth Orchestra played at Cheltenham Town Hall. On this occasion a recording was taken on DAT tape and some copies made for the players to listen to their own music.

Having had this tape cassette in my car for the past 10 years or so I decided to digitise the whole concert so it was preserved for the rest of time on youtube.

I have not altered the recording or cleaned up any noise so please realise this is not a perfect recording but simply a memory to share with any of the other players at GLO at that time, and also for future musicians to be inspired.

I have included an image of the full orchestra compliment which also included some guest players on the day.

It is also interesting to see that many of the orchestra have carried on their musical careers after the orchestra. To name but a few…

Charles Peebles who has gone on to conduct many other orchestras in the past few years.

Matthew Elston who now plays as Principal 2nd violin of the BBC Concert Orchestra and teaches music

Diggory Seacome – musical director – went on to become a Conservative Councillor!

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Sky lights up over Sicily as Mount Etna’s Voragine crater erupts

Sky lights up over Sicily as Mount Etna’s Voragine crater erupts


Display of volcanic lightning inside giant smoke and ash cloud over Europe’s tallest active volcano is Voragine crater’s first eruption in two years. The night sky lights up over the east coast of Sicily as Mount Etna’s Voragine crater erupts for the first time in two years. The giant plume of smoke and ash thrown up by the blast creates a dazzling display of volcanic lightning, a mysterious phenomenon seen in many of the most powerful volcanic eruptions.

It is thought that ash particles rubbing together inside the cloud could lead to the buildup of an electric charge that triggers the lightning strikes, much as a weak charge builds up on a balloon rubbed on a jumper

When the Icelandic volcano Eyjafjallajökull erupted in 2010, the combination of dust with ice and water from an overlying glacier produced a spectacular “dirty thunderstorm” that sent streaks of lightning leaping around inside the plume that drifted overhead.

The tallest active volcano in Europe, Mount Etna stands 3329m high and has been erupting for an estimated 2.5m years. In modern times, towns and villages in the foothills of Etna have been protected by ditches and concrete dams that divert lava flows to safer ground. The volcano has five craters: the Bocca Nuova, the north-east crater, two in the south-east crater complex and the Voragine. The Voragine crater formed inside the volcano’s central crater in 1945.

Volcanic activity in the region is driven by the collision of the African tectonic plate with the Eurasian plate. Magma from molten rock erupts as lava and ash and builds the volcano in the process.

The ash cloud from Mount Etna’s Voragine crater lights up the sky.
The ash cloud from Mount Etna’s Voragine crater lights up the sky. Photograph: Marco Restivo/Demotix/Corbis
Fire and ash emissions spew from Mount Etna’s Voragine crater.
Fire and ash emissions spew from Mount Etna’s Voragine crater. Photograph: Marco Restivo/Demotix/Corbis
Lightning highlights the ash as it spews out Mount Etna’s Vorgaine crater.
Lightning highlights the ash as it spews out Mount Etna’s Vorgaine crater. Photograph: Marco Restivo/Barcroft Media


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