I came across this website (link opens in a new window), via this other website (also opens in a new window) during a moment of leisurely browsing.
The first website is called SpaceWeather, and focuses on “news and information about the Sun-Earth environment”. It features a wealth of information about the weather in the Solar System and several high quality image archives of asteroids, aurora (Northern Lights), noctilucent clouds (a rare type of high altitude clouds that “glow” at night, without the help of light pollution) and eclipses. It also offers a nifty column on the left hand side for the curious to update themselves on matters such as current solar wind speed, coronal holes, interplanetary magnetic fields, and more.
The “other” website, Astronomy Picture of the Day, is a favourite of mine; it is simple, and “does what it says on the label”. Each day a new picture is uploaded, followed by a brief description written by a professional astronomer. No hidden quirks.
Mind you, I would particularly like to keep today’s picture- a wonderful shot of the 22nd July total eclipse, complete with explanation. No copyight infringement intended; click here to go to photographer’s website (new window also).
Total eclipse over Chongqing, China, 22/07/2009 (Credit & Copyright: Stephan Heinsius)
“Explanation: The daytime sky grew dark, the temperature dropped, and lights came on as Chongqing, China, was plunged into the Moon’s shadow during the July 22nd total solar eclipse. This serene, wide-angle view of the event looks to the east over the large, populous city from a newly constructed park. Despite thin clouds, it captures the shimmering solar corona just before the end of the eclipse total phase. This total solar eclipse occurred near Aphelion, the point in Earth’s elliptical orbit farthest from the Sun, and so the Sun was near its smallest apparent size. It also occurred when the New Moon was near Perigee, the closest point to Earth in the Moon’s elliptical orbit, making the Moon near its largest apparent size. The small Sun and large Moon made this the longest solar eclipse of this century.”
Small bits of trivia perhaps, but they could make a big difference, if we find ways to harness the power behind these phenomena. Suggestions?
If you live in England, you will most likely have half a week of school left before you can get up late in the mornings, wear “your own” clothes and spend your time the way YOU like. Although, if you are ever stranded inside on a rainy day, I have a few fun experiments for you to try, passing the time…
Hit the Floor
You will need:
a table or a desk, standing on flat ground
two coins of the same value
a stopwatch (optional)
two objects of different masses
Bangle and dictionary - which will land first?
Line the coins up on the edge of your table.
At the same time, gently push one coin off the side of the table, and flick the other one away (but not up) from the edge.
Which coin lands on the floor first?
Line your two objects of different masses up against the edge of the table.
Gently push both of them off the edge.
Which lands first?
Explanation: This is gravity at its best. Imagine the gravitational force like a piece of invisible string pulling the objects towards… who-/whatever is holding the other end of the string! In this case, it is the Earth. The Earth always pulls the string with the same force, in the same direction – “down”, as explained two blog entries ago. So, regardless of whether the objects travel different distances (the coins), or have the different masses (the bangle and the dictionary), because the Earth itself is so massive, the force that all of these experience is the same. They should all hit the floor at the same time.
Edible Lenses (Adapted from television show Backyard Science)
You will need:
a packet of jelly mix
a jelly mould (preferably flat-bottomed, otherwise, slice the top/bottom off to make two flat sides)
a round cookie cutter
a table knife
a comb
a light source, e.g. a torch
Make the jelly and let it set firmly in the mould – let it become a little bit more solid that it should be.
Tidy up the top and bottom with the table knife so that you have a flat piece of jelly of even thickness.
Use the cookie cutter to remove a round block of jelly, then cut it in half along the diameter.
Now, you have a thick, semi-circle of jelly. Shine the torch THROUGH the comb (teeth pointing downwards), so that you get many thin beams of light, onto the flat side of the semi-circle.
What happens to the beams of light on the other, curved, side of the semi-circle?
Cut a large square around the hole made by the cookie cutter (in the original sheet of jelly), and cut that in halves, down the middle. Shine the torch through the comb as before on the outside of the “hole”, i.e. a side of the square; now what happens to the light beams?
Repeat the experiment with different shapes of jelly to see what other patterns you can make.
Enjoy the jelly, bon appétit!
Explanation: When light passes through a medium (something that is not vacuum), it gets refracted. The speed of the beams usually slows down, as the light gets bent away from the path in which it entered (perpendicular, in this case).
Convex and concave lenses converge and diverge (respectively) light beams entering from the left.
[2]
Measuring the Speed of Light (c) (Adapted from Imperial College Physics Outreach)
This is something we often demonstrate on open days, as a way of relaying that science is not an elitist topic, but is readily accessible to all (no patronisation intended). Now, the result of this experiment is not really all that accurate, but it is plausible as a method to find the required constant. See the explanation for further details.
You will need:
a chocolate digestive biscuit (on a plate)
a microwave
a ruler
a calculator
Place the chocolate digestive biscuit CHOCOLATE SIDE UP on the plate.
Put the whole thing in the microwave at high power for approximately one minute – small peaks should have formed in the chocolate.
Using the ruler, measure the distance between the peaks in the chocolate. Convert that into metres. (1000 millimetres = 100 centimetres = 1 metre)
The average frequency of a commercial microwave oven is around 2.45 GHz [1], which is 2.45 × 109 Hz. Multiply the distance found in part 3 with this value, and the result is your very own record of the speed of light!
Explanation: The microwaves in the oven will melt the chocolate, and resonate with the material, this cause the little peaks to arise; they are the nodes of a standing wave, formed from resonance. One of the wave equations is c=fλ, where c is the speed of light (measure in metres per second), f is the frequency (in Hertz, or Hz) and λ (greek letter lambda) is the wavelength (in metres); this was used to find the speed of light, which, for a vacuum, is 299,792,458 metres per second, and often approximated to 3 × 108 metres per second.
Taking a brief pause from the deficit model of learning, I would like to use today’s post to spread the word about an exhibition I went to see with my 7- year old brother.
The Centre for Life (link in “links” section) is a large, open plan gallery, filled to the brim with vibrantly coloured “stations”, marking out the different sections, each with their own focus. Interactive activities are mixed with posters describing the background theory for each element, creating an atmosphere where the visitor is let loose to “discover” scientific ideas instead of being told how everything works. For those more pro-active, there are plenty of LCD screen based challenges, e.g building and maintaining a landfill site, becoming a weather forecast presenter; for the younger visitors, there are also games and construction activities mainly centering on examples of natural selection. Given its name, the museum weighs in heavy on the expected biological and social science exhibitions, but they range from survival-of-the-fittest all the way to basic stem cell research, so there is something for everybody to muse about.
Looking up...
Included in the price (£ 5-8 per person, depending on age and other circumstances, family tickets also available) are entries to the different shows and/or rides offered (may vary). I caught three on the day; the motion ride, a just-for-fun screened adventure with mobile chairs, will definitely have the younger audience in a giggle; “We are Astronomers” in the planetarium, sitting in plush chairs gazing up at a hemi-spherical screen – large enough to be awe-inspiring, small enough to avoid being overwhelming to younger guests. Finally, Dino Engineering, a theatre show aimed at children, was informative enough to engage the attention of the youngsters for the duration of the show whilst forgoing the patronising nature such shows may have.
As an adult, I thoroughly enjoyed myself, and my brother seemed to have had a good time too, only glitched by a couple of “scary, life-size, moving, growling dinosaurs with big teeth”, then again, opinions on those things are subjective, are they not?
So, if you are around the North East of England, and have some spare time, I would definitely recommend you pay the Centre for Life a visit. Now, if this blog was in better circulation, maybe I could have charged them for this. Well well, that day will come.
Either way, I hope You come back again, as I have planned some (yes they are) FUN DIY experiments regarding last week’s topic of choice – GRAVITY.
Well, magnesium probably does play a part in keeping Earth in its orbit, but the chemical compositions of both the Earth and the Sun do not contain enough quantities of magnesium for it to be of significance. [1]
No, what I am getting at here is the force that keeps Earth in its orbit, GRAVITY.
GRAVITY
If you are five years old and, more likely than not, reading this with mummy and/or daddy, all you need to know about gravity for now is that it makes things stick to the ground. Gravity is something that, unfortunately, makes a dropped ice cream fall to the floor; but it also keeps you from floating away uncontrollably if you jump up.
If you are ten, you may know that gravity is a force, that does not only exist on Earth, but also on other planets and stars. The gravitational pull of the Moon is what gives us tides on Earth.
If you are fifteen, and doing GCSEs if you live in England, it is time to get to grips with some equations and numbers*; but first…
The gravitational force attracts things with a mass to each other; whilst standing, the Earth pulls you towards its centre (down), although the surface (ground) prevents you from sinking in. At the same time, because you have a mass too, you are pulling the Earth towards your centre of mass as well. However, due to the fact that Earth is so much larger, you can barely notice the Earth move.
Gravitational force increases when: [2]
the masses of the objects involved increases
the distance between the objects decreases
This centre of mass I am talking about is, for any spherical (round) object, is essentially its centre. On an object that is not spherical, this becomes a little bit tricker, so we shall not look at it right this moment.
"Down" is the same direction everywhere on Earth.
If you are twenty, you will either already know all you need about the gravitational force for your field, or you will have associated yourself enough with the quantum world to completely lose interest in gravity.
As gravity increases with the object’s mass, it is the reason why you and I stick to our planet Earth, and (partially*) why the Earth stays nicely in its orbit around the massive Sun.
*The equation and numbers, as well as the explanation of “partially” be our next focus.
[1] Chemical composition of Earth, Venus, and Mercury; John W. Morgan and Edward Anders; Proc Natl Acad Sci U S A. 1980 December; 77(12): 6973–6977
[2] BBC Bitesize, KS3 Science, Forces and Motion (accessed on publishing date)
Yes. Hello indeed. Cutting straight to the chase: science – is for nerds, is it not? If so, then I for one, am an out and proud nerd.
Compared to, say, fifty years ago, science education appears to have severly lost its lustre. Perhaps not because it has ceased to be important (it SO has not), or even due a general lack of interest (which I am certain is untrue).
I believe it has more to do with the fact that the natural sciences – physics, chemistry and biology (ranked in order of “coolness”) – are classically considered “hard subjects”, that only bookworms and extremely short-sighted people pop their corks at. Again, not true. Science is for everybody. Maybe not suitable for ages 0-3 due to small parts though.
Taking a random sweep around the educational section of any bookshop, I have found that some (primarily CGP, but they do seem to be the most popular) of the current editions of GCSE revision guides have shrunk the three aforementioned subjects into a single book, that is only marginally larger than the revision guide for e.g. physical education (no offence there).
Furthermore, not only are the contents lacking in pure science (albeit Newton’s laws, the breakdown of crude oil, and the Nitrogen cycle are awarded their due pages, do not worry), they were spread thick and greasy with social science. Issues such as obesity (in the social sense), over-population and how to press olive oil could potentially make a difference to a young person’s life, but I am certain that these young people are in these particular classes to learn the real thing, and not the watered down version.
This blog does not wish to, in any way imaginable, take a stab at other fields of study; my aim is to provide an online science resource that goes straight to page 1, no foreword. As I am still new to this, and only exploring my own interests and ideas, the theme of each post may vary wildly, but please persevere, and maybe this could be the start of something excellent (no arrogance intended).
Now I realise that I have effectively composed a foreword despite what I have written above. Oh well. First “real” post – “Why magnesium does not make the Earth orbit the Sun”*, coming up soon.
*Idea courtesy of a Young Person whose exam paper I marked a year ago, which partially inspired this blog. Thank you.
The Real World for Young People 