As part of GCSE Physics students learn the idea of an object that reaches terminal velocity when it is moving in a fluid. A great demonstration of this idea is through the example of objects in free fall. And what better object to think this idea through than a skydiver!
The embedded video bring this idea to life. Velocity values of an actual skydiver are given through the different phases of the journey. Right at the very start when the diver jumps off, the weight is the only force acting on the vertical plane. By using Newton’s 2nd law you can work out that the acceleration is all due to gravity at that point. As the diver gains speed due to this acceleration, the air resistance (or drag) also increases. Now the resultant force downwards is smaller and so is the acceleration. Nonetheless there is acceleration downwards and the velocity is still increasing. Eventually the drag increases so much that it is enough to counteract the weight. At this point the forces are balanced and the acceleration is zero. But by this point the diver has a substantial velocity. As such the diver will continue in free fall at a constant velocity. This is what is known as the terminal velocity.
Once the parachute is deployed, the drag increases and the resultant force is now upwards as the drag is more than the weight. This causes deceleration. At the same time the reduced velocity decreases the drag. But there is still deceleration so the diver keeps slowing down. Until the point when the drag is once again equal to the weight. The diver then reaches a second terminal velocity.
This is all explained in the video as well. So hit play on the video and be taken on a skydiving ride joined up with Physics revision. Good luck to all the Physics students taking their exams tomorrow.
During my online GCSE Physics tutoring sessions I mention how Electricity is made. And a key extension to that is also how electricity is distributed. The system is called the National Grid and is Great Britain’s electrical transmission and distribution system. In my 2nd year Summer Engineering placement I worked for an electrical distribution company and visited substations.
The National Grid and pumped storage are both part of GCSE Physics, albeit module P1 for AQA Physics, for which the exams have already been and gone in 2017.
Nonetheless the following website is absoltuely amazing in giving you a live up date on nationwide electrical production. It gives you a live pie chart on the different sources of energy, and the distribution of renewable vs non renewable. Not only that but it also gives you an indication on how much pumped storage electricity is available. Pumped storage is in the Physics syllabus as well.
Some other pretty cool things you can see are that there are direct electricity lines between the UK, France and Holland. That way electricity can both be imported and exported.
So click on this link here and check out what’s happening in terms of the National Grid right now.
National Grid : Live Status
It was quite the most incredible event that has ever happened to me in my life. It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you.
– Ernest Rutherford
Being able to write out the key results of Rutherford, Marsden and Muller’s famous gold leaf scattering experiment is one of the requirements of the GCSE Physics syllabus. It comes up both in AQA and iGCSE Edexcel that I regularly tutor every year. This is usually accompanied by a comparison with the older “Plum Pudding” model of the atom. On this particular post I have embedded an invaluable video that I use for my online Physics tutoring sessions. A must watch for a deeper understanding of Rutherford’s experimental set up and his findings.
Gold leaf nucleus
Writing out the correct answer on a test is one thing, and understanding the human story of ingenuity, perseverance and scientific intuition is another. We tend to learn things better when they are presented as stories and great breakthroughs often challenge the status quo of the time. What he found was mind boggling at the time, and even today it is hard to imagine how empty an atom actually is.
In this BBC documentary Professor Jim Al Khalili visits the actual laboratory in Manchester where Rutherford got his two assistants to explore the atom in detail. He shows the actual equipment used and the story of how one seemingly random decision by Rutherford ended up unraveling the mystery of the atom. The video is part of a BBC series called Atom. A must watch for all GCSE students with the key part being from 17:30 to 25:07. The video auto-starts at this point on this link. So press play and be taken on a journey of the most important chapter in the discovery of the inner workings of the atom.
Electricity. We all use it daily but how is it actually made and where does it come from? Tutoring how electricity is made is one of my favorite parts of teaching Physics. In this BBC video you will see a couple of young children being shown around a power station, and then seeing an excellent, clear demo of a kettle, a turbine and magnets that show how a power station actually works.
When I was 18 I was sponsored by Rolls Royce’s Industrial Power Generation branch of companies, and I took a year out with them before joining university at 19 as a first year. That year turned out to be an invaluable experience and it has come in so very handy when tutoring. I worked in a steam turbine and diesel engine factory, WH Allen of Bedford. And then a year later I worked for an electrical power generators and transformers company. I got to know a lot about power generation at a young age.
Making electricity is no magic though, and relies on some simple part of Physics all coming together. Amazingly this video is pitched for primary school children, but in reality it is invaluable during my online GCSE Physics tuition sessions. The kids are transported by curios cat the narrator to a gas-powered power plant. They get to see how a boiler, steam turbine and a generator work through a simple demo of a kettle boiling steam into a bunch of spoons set up as rotating vanes. There’s also a simple demo of electromagnetic induction using magnets, a conductor and a LED lamp.
So if you are preparing for your GCSE exam, or are just curious to how electricity is made, then click away on the link above and start your journey!
Science has some pretty awesome and cool things. Some of them you really have to see to believe! Recently I started a Facebook page for my tuition services. As many of my friends, clients and students know, I am a huge fan of video with my music. And recently Facebook live allows me to livestream gigs to friends across the world. So I took that idea to heart and livestreamed a Physics lesson for about 3 minutes.
In this very simple lesson, I show a very cool demonstration of a magnet floating, or levitating in air. I explain why in the video. Please do comment if you that has got you thinking.
The Google doodle today shows a massive landmark in Science, the day we found the speed of light. This was done by Danish astronomer Ole Rømer in 1676. More recently Freddie Mercury would sing about travelling at the speed of light in the Queen song, Don’t Stop Me Now. He did have Brian May in the band who has a PhD in Astrophysics.
Going back to the serious business of light having a speed..How can light even have a speed? It is impossible to “see” light having a speed directly. Light just seems to instantaneously “be” everywhere as soon as the sun rises or a light switch is flicked on.
340 years ago, which is a long time ago now in the context of modern Physics, the Danish astronomer did work this out. His genius laid in the fact that he worked out a peculiar quirk in exactly when Jupiter’s moon Io popped into view through his telescope. It appeared to pop into view at different times at different times of the year. It shouldn’t have because celestial mechanics are very stable and steady indeed. He questioned the very assumption that light itself must be taking shorter or longer to get to the earth from Io. This is what the Google doodle shows today. Doing calculations with the speed of light are fairly standard at A Level Physics, but they also come up occasionally at GCSE Physics as well.
Professor Brian Cox explains this much better in his short video that I have linked below. So click away and learn about this big part of Scientific history.
Now this is a deep deep question. And one that we all ask. In fact, do we really know if the universe is even finite at all? Fortunately the answer to this is covered at school in the context of Astronomy in Physics. Finite or infinite, according to the latest information on Physics, and the measurements we have made so far, it is possible to get a very good picture on this. But how can one put this into context, or visualise this?
This is a video I show to all my Physics students, it is a totally mindblowing visualisation of the universe, zooming out of the earth, into the solar system, how the solar system fits into the Milky Way galaxy, and where the Milky way fits in amongst many many galaxies. Produced by the American Museum of Natural History, and with a beautiful ambient trance like soundtrack this short video will take you on a very long journey away and then back from earth.
The distances are measured in how fast light travels, because in the big scheme of things light is very slow indeed. While it takes roughly 8 minutes for light to get from the Sun to the Earth, it takes millions of years to get to us from the outer reaches of the universe.
This video fascinates all my students, it will leave you stunned and in awe knowing where you fit into the big scheme of things. It is a total joy to be able to share this with my students, and I never get bored of watching it again and again, a truly great Physics resource. Hit play and enjoy the ride.