How to Understand Electricity: Volts, Amps and Watts Explained on Appliances

© Eugene Brennan

This comprehensive guide for consumers and students explains everything about volts, amps and watts and how they apply to home appliances and circuits. The equations are really quite simple, and you'll find some examples on how to apply them to home appliances.

Electricity 101: Understanding the Basics

In this tutorial, you'll learn about:

• Volts, watts, amps
• Power consumption of appliances and kilowatt hours (kWh)
• Ohm's law and resistance
• Resistivity and how it affects the resistance of a material
• Fuses and how they protect wiring and appliances
• How electricity is produced
• Devices used to measure voltage, current and resistance
• The effects of electric and magnetic fields
• Conductors, insulators and superconductors
• The basics of AC and DC
• Arcs and sparks
• Power supplies and voltage regulation
• Tracking electricity usage in the home

How to Solve Projectile Motion Problems: Applying Newton's Equations of Motion to Ballistics

Public domain image by Prosaica on Pixabay

Physics is an area of science which deals with how matter and waves behave in the universe. A branch of physics called mechanics deals with forces, matter, energy, work done and motion. A further sub-branch known as kinematics deals with motion and ballistics is specifically concerned with the motion of projectiles launched into the air, water or space.

Conversations with ChatGPT: Shallow Truss Forces

t history

Created by ChatGPT

You said:

When a force acts down on the apex of the truss, the forces in the tie can be greater than the load acting down on the apex. And if the slope of the truss becomes very shallow, the tension force in the tie can become huge and tend to infinity as the angle of the slope tends to zero.

"Bridges Finished"

Excerpt from the Dublin Gazette, 1768. Image attribution: Virtual Record Treasury of Ireland

Creative Commons License CC BY-NC 4.0 (Attribution-NonCommercial)

Both the Virtual Record Treasury of Ireland and JSTOR are rich sources of historical records. The former attempts to at least partially replace records which were destroyed when the Public Records Office, located in the Four Courts, was destroyed by a large explosion and fire, possibly triggered when Free State forces shelled the building in 1922 at the outbreak of the Civil War. JSTOR (Journal Storage) is a "digital library of academic journals, books, and primary sources founded in 1994". The excerpt above is one of the several Kilcullen-relevant references in the Dublin Gazette, an official newspaper of the Irish Executive, the British-controlled government in Ireland based at Dublin Castle, between 1705 and 1922.

(Thanks to Liam Kenny on the Harristown Station FB page for letting me know about this, which was referenced in Irish Stone Bridges, O'Keeffe & Simington, Blackrock, 1991)

Conversations With ChatGPT: Flight Ceiling of Aircraft

Created with Grok.

You said: 

“Hello.”

ChatGPT said:

Hey there! How’s it going? What’s on your mind today?

You said:

“Would it be possible for more advanced passenger aircraft to fly at higher altitudes? I know there would be less oxygen, so there would be an issue with engines running efficiently, but there would be less drag also.”

Sub-Atomic Particles are Points

Created by Grok

Classical physics portrays subatomic particles as being like snooker balls—hard spheres with a charge. In this model, known as the Bohr model, the nucleus of an atom is made up of positively charged protons and chargeless neutrons. Negatively-charged electrons whizz around the nucleus, so the whole arrangement is like a mini solar system. Electrons when they move are what constitute an electric current, and an electrical generator simply "pumps" electrons. Electrons are also what are involved in chemical reactions: e.g. when hydrogen and oxygen combine to make water, or sodium and chlorine react to form sodium chloride, common table salt.

Work at Dunstown 400kV Substation

Groundworks at Dunstown 400 kV Substation. Image © Airbus, Maxar Technologies.

On a section of land adjacent-to and SE of the existing substation.

Maybe extra transformer capacity being added or other electrical infrastructure. I'm going to have to visit Google Earth, rather than Google Maps, as the former has historical satellite imagery.

 

Edit: Possibly preliminary groundworks for this: The connection of a "a high-capacity 400 kV (kilovolt) underground electricity connection between Dunstown substation in Co Kildare and Woodland substation in Co Meath." This is part of the Kildare-Meath Grid Upgrade (or Capital Project 966).

Microgeneration and Athgarvan Mill

Athgarvan corn mill in 2001. © Eugene Brennan

I've added links below to a list of electrical power generating sites in Ireland in a Wikipedia article, and also written answers from a Dáil Éireann debate of Tuesday, 26 Jan 2010 on the Oireachtais.ie website. There may be sites that generate lower output, not listed in these resources. According to a list referred to by Minister Eamon Ryan and provided by EirGrid and ESB Networks, Athgarvan Grain Company Limited's installation in Athgarvan was generating 20 kW from its small hydro turbine. (The owner showed me this in 2001, but I can't remember anything about it). Also Silliot Hill was generating 1.255 MW from methane produced by the landfill. An installation at Celbridge Mills was listed as generating 55 kW.

Let's Do Some Calculations: How Much Water?

© Eugene Brennan

I know I'm getting nerdy about this and becoming somewhat obsessed, but let's do some calculations for the total amount of water which has been flowing through the town per day.

Releases of water from Golden Falls dam in Ballymore Eustace have been unusually high over the last week. Some of this water will have flowed through the penstocks (large diameter pipes) to power the alternator and generate electricity. If power from the hydroelectric station can't be accepted by the grid and water level is too high in the lake supplying the dam, it has to "overflow". It's released through "doors" known as sluices, which are raised by electric motors. It then flows down concrete spillways into the river.

Examples of Forces in Everyday Life and How They Affect Things

© Eugene Brennan

In this first part of a two-part tutorial, we'll learn the absolute basics about forces!

What's covered:

• Definitions of force, mass, velocity, acceleration, weight
• Vector diagrams
• Adding and resolving vectors

What Is a Force?

We can think of a force of a force as a push or pull.

 

Newton's 3 Laws of Motion: Force, Mass and Acceleration

An infographic explaining Newton's three laws of motion. © Eugene Brennan

Mechanics is a branch of physics which deals with forces, mass, and motion.
In this second part of a two part tutorial, you'll learn the absolute basics!
In the first tutorial, Examples of Forces in Everyday Life and How They Affect Things, we learned what force is and explored the various types of forces in the world around us.

What's Covered in This Guide?

• Newton's three laws of motion and how an object behaves when a force is applied
• Action and reaction
• Friction
• Kinematics equations of motion

From the article "Examples of Forces in Everyday Life and How They Affect Things". © Eugene Brennan

Replica Gun Discussion on Liveline

Created by Grok.

A discussion on RTÉ Liveline today was about "Airsoft" type guns on public display in shops. Under the Firearms Acts 1925, revised to 2023, these guns must have a muzzle energy of less than 1 joule to avoid being classified as firearms requiring a license.

What's a joule?

It's the Système International (SI) unit of energy or work done.

Energy = power x time

So 1 watt for 1 second = 1 x 1 = 1 joule.

Think of a 1 watt bulb turned on for 1 second; that consumes 1 joule of energy.

Big Picture Science Podcast: A Real Gas

Created by Grok

Did you know, some gasses have a colour (like chlorine), many are invisible and have have no taste or smell (such as oxygen and nitrogen), and yet others are totally unreactive—the noble gasses, such as neon, argon and xenon? Also steam is an invisible gas. The stuff we see coming out of a kettle is condensed steam, but close to 100 degrees Celsius.

In this episode, Mark Miodownik – Professor of materials and society at the University College London and the author of It’s a Gas: The Sublime and Elusive Elements That Expand Our World, talks with executive producer of BPS, Molly Bentley.

Items for Sale in Kilcullen, Circa 1900

Image courtesy The National Library of Ireland.

"Sides of pork, brooms, Cadbury chocolate and cocoa and The Freeman's Journal: some of the items for sale in Kilcullen circa 1900."
 
I've been examining photos from the Lawrence Collection again and zooming in to see whether I can spot any details I may have missed. The collection is available online on the National Library of Ireland's website. I first viewed the photographs on a visit to the NLI around 1982. In those days, before digitisation, photographic records were stored on rolls of microfilm and had to be viewed using optical microform readers.
The Lawrence Collection consists of approximately 40,000 glass plate negatives of buildings and scenes from life in Ireland, photographed between 1865 and 1914. The photographs were taken using large-format cameras and because of the size of the glass-plate negatives, resolution is quite high. There are 25 photographs of buildings and streetscapes in Kilcullen and its hinterland, and the collection became available to access online over 10 years ago.

You can view it here.

All images courtesy the National Library of Ireland.

The building at the corner of the entrance to the Valley Park, originally Andrew Maloney's premises.

 

Signs for "The Freeman's Journal" outside what is now Bardon's Pub. The premises was originally a hotel and then a pub and grocery.

A shop in Upper Main street which is now the premises of Dowling Property.

Near Centric Health.

Dublin House, now Woodbine Books. It was the premises of Denis Brennan, auctioneer, pub and drapers.

Leaky Schrader Valve

Hand truck tube. © Eugene Brennan

So being a member of 60 Facebook groups and squandering a lot of time nattering about all sorts of things, I try to get at least one useful thing done per day. Today was damp, so dealing with weeds in the driveway was out of the question. One of the items on my ever-growing-longer "to do" list I hadn't got around to was fixing the wheel on my hand truck which always seemed to be soft when I went to use the truck. I thought it might be a puncture caused by running over thorns (what usually happens with the bike). However doing a water test showed the Schrader valve was leaky. There's a special tool for taking the innards out of the valve casing, but I usually just use a needle-nose pliers. These valves have a conical part that sits into a conical seat, the cone being pressed against the seat by a spring. I blew out the valve with compressed air, gave the red ring that seals against the valve body a wipe and put the bits back together. This time there were no leaks whatsoever after the water test.

Removing the Valve innards. © Eugene Brennan

C

Check valve. © Eugene Brennan

© Eugene Brennan