Iconic Items in the Science Museum, London

Some photos of iconic items in the Science Museum, London, taken when I was there in 2017: The Apollo 10 command module "Charlie Brown", complete with the effects of re-entry on the underside, A Saturn V second-stage engine, a cut-away of a Parsons steam turbine, and "Puffing Billy", the world's oldest steam locomotive.

Apollo 10 capsule "Charlie Brown" in the Science Museum, London © Eugene Brennan

 

Underside of Apollo 10 capsule "Charlie Brown"  © Eugene Brennan

Saturn V second stage engine © Eugene Brennan 

 

 

Parsons steam turbine © Eugene Brennan

"Puffing Billy", the world's first steam locomotive  © Eugene Brennan

 

 

Pocket Weighing Scales From Temu

Pocket scales from Temu © Eugene Brennan

Playing with my latest Temuu gadget. A pocket scales which cost less than €5. Without proper calibration weights, it's hard to tell how accurate it is, but this is what it displays with some weights I bought.
Not sure what I'll use it for 🙄. No, I'm not becoming a drug dealer, but I like measuring instruments.

There used to be a balance in our classroom in the BNS, when it was based in what is now Kilcullen Library, along with glassware and other scientific equipment, hidden away in a cupboard (including a bottle of mercury which is highly toxic). They may have dated from before the war. We never used those items though.

Some information here on the teaching of "Rural Science" and "Nature Studies" in primary schools in the early part of the 20th century. The teaching of these subjects became optional in 1934, more emphasis being placed on using the time for teaching Irish:

ELEMENTARY SCIENCE IN IRISH PRIMARY
SCHOOLS FROM THE LATE 1800s TO THE
PRESENT DAY

Some more photos of what the scales indicated for the various weights I bought.

 

Cartoon Capers

Image created using Bing Image Creator

You know those cartoons where Wile E. Coyote uses a giant magnet in one of his ill-fated plots to capture the Road Runner? It‘d be brilliant if such magnets exited, but unfortunately not. Gravity is one of the forces that act at long distances (well strictly gravity is not a proper force, but that's another story), however the force of a magnet is relatively localised to a region close to its north and south poles. So magnets in scrapyards can lift tons of metal, but they have to be lowered until they're nearly touching scrap. If the field strength of a magnet is increased sufficiently, the force can extend outwards some distance, but the force still obeys an inverse square law with respect to distance. So for instance let’s say the distance from a magnet is one cm. The force will have a certain value. At two cm, the force decreases to one quarter that value and at three cm to one ninth the value (nine being the square of three). At four cm, it’ll have fallen to one sixteenth the strength it was at one cm, and so on. To complicate things, force follows an inverse cube law close to a magnet, which causes an initial rapid drop-off in attractive force. Many parameters in nature follow an inverse square law, for example the brightness of an omnidirectional (the same in all directions) light source or the loudness of a sound source as an observer moves away from the source. Gravity also follows an inverse square law and the force of attraction between two bodies is proportional to the product of their masses (Either body being more massive increases the force) and inversely proportional to the square of their distance apart. (all of this discovered by Isaac Newton, the scientist and mathematician). The force of gravity of the Sun on a 70 kg person is about 42 g.

Parabolas in Nature and How We Use Them in Commonplace Items

 

Image created using Geogebra © Eugene Brennan

The parabola, a geometric shape that can be defined as the locus of points equidistant from an axis called the directrix and a point called the focus.
Parabolas crop up everywhere in nature and in things we make. If you kick a ball or throw a stone up at an angle into the air, the trajectory or path traced out is in the shape of a parabola. Similarly for a jet of water or projectile from a gun.

A stream of water from a jet follows a parabolic trajectory. Image courtesy GuidoB, CC BY-SA 3.0 Unported via Wikimedia Commons

Satellite dishes, radio and optical telescopes, flashlights and car headlamps all have parabolic reflectors because of a useful property of the shape: Rays from the focus of the parabola hitting the reflector are "bounced" outwards in a parallel beam (in the case of a light, heat, microwave or sound source) and vice versa for incoming parallel rays so they're focused on a detector (for a satellite dish or telescope).
Parabolas are also one of the range of shapes used for the nose cones of aircraft. In this case, the shape is a 3D version of a parabola, produced by rotating it around its axis.

Flight Controls

Image attribution: Piotr Jaworski, CC BY-SA 3.0 via Wikimedia Commons 

A nice little animated GIF from Wikipedia showing how the flight controls in an aircraft work. The rudder pedals and control column (also known as the control stick, control yoke or control wheel) or joystick on more modern aircraft, move the control surfaces to make the aircraft roll, pitch or yaw.

A): aileron, B): control stick, C): elevator, D): rudder.

On early aircraft, the linkages would have been steel cables like bicycle brake cables or car handbrake cables, and control surfaces would have been moved directly using only human power from the flight controls. This system is still used on some light aircraft. As aircraft became larger, it would have been infeasible to move heavy control surfaces by hand simply because of their weight and aerodynamic forces on the surfaces (like when you try to control an umbrella in high winds) so hydraulics was used to move the surfaces (similar to the way a digger works.) Nowadays, most aircraft are fly-by-wire, meaning when the pilot moves the stick, a control signal is sent to either electrical or hydraulic actuators that move the control surfaces. The Airbus A320 was the first commercial aircraft to use this system in 1987 although fighter aircraft previously used a version of the technology. Fly-by-optics is another development, allowing higher data transfer rates and immunity to electromagnetic interference (EMI).

There's a discussion about fly-by-wire on Aviation StackExchange here:

https://aviation.stackexchange.com/questions/21679/airbus-is-to-fly-by-wire-as-boeing-is-to