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These Bitesize pages will help if you need to recap on the basics of magnets.  A magnetic field is produced whenever current flows through a wire.  The magnetic field is represented by a series of concentric circles around the wire, as shown below. Magnetic field lines around a current carrying wire.  image: physick wiki The direction ... <a title="charged particles in magnetic fields" class="read-more" href="https://mrmackenzie.co.uk/2021/11/charged-particles-in-magnetic-fields/" aria-label="Read more about charged particles in magnetic fields">Read more</a>

An electric field can be used to accelerate charged particles.  Conservation of energy tells us that the work done by the field is equal to the change in the particle’s kinetic energy.  The speed of the particle can be determined if its charge[...]

At the end of Our Dynamic Universe, we considered big things like stars, galaxies and the Universe itself.  Now the Particles and Waves unit brings us to particles so small we need groups of them just to make a single atom.  Is there a connection? Why do we study particles? from mr mackenzie on Vimeo.&#160; The Standard Model An elementary ... <a title="fundamental particles: quarks, leptons and the standard model" class="read-more" href="https://mrmackenzie.co.uk/2021/11/fundamental-particles-quarks-leptons-and-the-standard-model/" aria-label="Read more about fundamental particles: quarks, leptons and the standard model">Read more</a>

It&#8217;s complicated and cosmologists are not certain.  One of the issues is only being able to see about 4% of the mass in the universe &#8211; the stars, planets, gas and dust.  About 25% of the mass of the universe is Dark Matter.  It&#8217;s &#8220;dark&#8221; because it doesn&#8217;t emit light that enables us to see ... <a title="dark matter, dark energy and the end of the Universe" class="read-more" href="https://mrmackenzie.co.uk/2021/11/dark-matter-dark-energy-and-the-end-of-the-universe/" aria-label="Read more about dark matter, dark energy and the end of the Universe">Read more</a>

You might remember that we looked at some paradoxes when we studied special relativity earlier this term.  Here is another situation where a paradox can arise.  The German astronomer Heinrich Olbers (1758–1840) asked why the night sky was dark.  At the time, astronomers believed that the Universe was both infinite and steady state (unchanging), so ... <a title="evidence supporting the Big Bang model: 3. Olber&#8217;s paradox" class="read-more" href="https://mrmackenzie.co.uk/2021/11/evidence-supporting-the-big-bang-model-3-olbers-paradox/" aria-label="Read more about evidence supporting the Big Bang model: 3. Olber&#8217;s paradox">Read more</a>