What is Light Pollution?

When I first started learning about best practices for installing outdoor lights, I came across some articles that warned about the effects of landscape lighting on the environment. Ever hear of light pollution? If you have and you’re wondering, “what is light pollution?” then this article is for you.

In short, light pollution refers to the negative effects of artificial lighting on the environment and all of its inhabitants. A good way to familiarize ourselves with the subject is by delving into some of its more prominent elements. So, in this article, we’ll look at some important terms that you should know about before you install your landscape lighting system, or if you already have a outdoor lighting.

Sky Glow

Sky glow is a natural occurrence, produced by celestial objects – the sun, moon, stars, nebulae, etc. But, the world’s collective use of electrical lighting can obscure some of these night-time sights and interrupt natural cycles. Human-created sky glow, the illuminating of the sky at night by way of artificial light, is one cause of these environmental alterations and falls under the heading of light pollution.

The phenomenon of sky glow results from light sources that point toward the sky and those that do not have sufficient shielding. It is also a consequence of light reflecting from a surface, or multiple surfaces, toward the ground, which increases the visibility of the resulting glow. Because of the growth of the landscape lighting market, sky glow is often mentioned in relation to residential lights.

Still, other sources of night-time light, such as lighting for commercial structures, urban landscapes, Christmas and events, streets and major roads, tunnels and galleries, campuses and other areas, also contribute to the brightness of the glow. And much of this light reflects off of natural elements, like dust particles, molecules of gas, and water. This reflection creates a mass dispersal of light that contributes to sky glow.

Glare

The term, glare, refers to excessive brightness produced by artificial lighting. It can occur when a light source is exposed, due to partial or no shielding on the fixture, or when a source of light points toward the sky. Spotlights, which enable the installer to aim the light source high or low, and uncovered luminaires, like in-ground well-lights, can work against a smooth, well-blended arrangement of light and darkness. The result is an uncomfortable experience for the eyes. Additionally, bulbs capable of high light output can contribute to glare, causing eye strain, subsequent headaches and other forms of discomfort.

Over-Illumination

Over-illumination can also refer to light that is too bright. But, it differs from glare in that its application is more specific. While glare refers to excessive brightness in general, over-illumination refers to light that is too bright for the particular activity that the light is intended to support. A common example appears in the form of buildings that employ natural light from a skylight in conjunction with artificial lights in the same area. You might find this condition in some museums, office buildings, and the like, where workers perform daily tasks.

Commercial buildings where lights remain on overnight, after most or all employees have gone home, are also examples of over-illumination. And the term is often used in reference to residential areas to describe occasions when a light is left on in an unoccupied room, or when a home’s outdoor fixtures emit light that is unduly bright for the task of providing illumination for a party or accentuating features of the landscape. Whether the site is a grocery store, a warehouse, or an otherwise cozy home, over-illumination can produce significant consequences for those exposed to it.

Prolonged exposure to excessively brilliant light can induce migraine headaches, which could mean a higher chance of brain lesions and disrupted blood flow for the affected persons. It can cause fatigue, impairing employees’ ability to perform at their best in the workplace. It can also lead to hypertension, cardiovascular disease, and other illnesses. In addition, over-illumination disrupts the natural cycles of various kinds of animals, as well as those of human beings.

Light Clutter

Too many artificial light sources arranged together in a particular space produces a phenomenon known as light clutter. Often a consequence of such night-time luminaries as business lights and inappropriately organized streetlights, light clutter is sometimes the unintended result of an attempt to provide visible working environments, security for pedestrians, and a means of safe automotive travel at night. Other times, it is the result of an intention to create eye-catching street-level fare.

Particularly in the case of illuminated advertisements, some light sources are designed with the hope of drawing the attention of travelers as they commute to various destinations. Traditional brightly-lit billboards, orbital billboards, and storefront lighting, are all examples of advertisements that are used to grab attention. Accordingly, where these sources are crowded together, they can create a quality of light that obscures the presence of various objects, whether these objects are mobile or stationary.

Of course, light clutter can also occur in our own yards. A landscape lighting design that works against providing a fair amount of distance between light sources produces effects in residential areas that are similar to those that we find in more industrial areas. And, because it is closer to home, it also increases the chances that light clutter will directly affect homeowners and their families while they are in the house.

Light Trespass

Light trespass describes those instances when light shines in undesired areas. More specifically, the term applies to light shining onto another person’s property, or into their home. This can occur as a result of a contractor’s neighborhood design, where lighting is incorporated into the design, or as a consequence of a neighbor’s landscape lighting. In both cases, the person whose property becomes the recipient of the trespass, could find themselves exposed to the whole range of photo-pollutants – from sky glow to light clutter.

Dark Sky Lighting

Dark sky lighting is not a form of light pollution. On the contrary, it is a set of guidelines that can help minimize the incidence of light pollution in areas where light sources are likely to be used with great frequency. The primary aim of dark sky lighting is to use only the kind and number of light sources necessary in a responsible fashion.

According to the International Dark Sky Association, there are five principles that we can use to decrease light pollution. We can begin by determining whether a particular light, or set of lights, serves a specific purpose beyond the singular aim of enhancing aesthetic appeal. If the light is not required for a certain function, like security or safety when walking the landscape at night, then the light is not essential.

We should also be careful to direct the light of a luminaire only to the area where it is needed. Here, using a light that is appropriately shielded, so that little or no luminescence crosses into unintended areas, is important. If any of our lights do reach into unintended areas, then it’s a good idea to check whether we can change the placement of the fixture (likely with respect to its height, as a higher positioned light increases the potential for light trespass) and the direction in which the fixture aims its light. If neither of these measures are possible, then it is probably best to replace the light fixture (or to have it replaced).

Limiting the degree of brilliance that a fixture emits is also a key principle of dark sky lighting. This is particularly important, given the fact that surfaces can reflect light and, ultimately, contribute to sky glow. We can allow for environment-friendly lighting by using bulbs that emit only the least amount of light required to serve the specific function of a given light fixture. For this, we will want to know the degree of brightness that a given bulb produces.

(A bulb’s brightness is measured in lumens. The latest bulbs often come with a Lighting Facts Label that tells you about a bulb’s level of brightness, the estimated yearly energy cost, the life of the bulb, its light appearance with respect to warmth and coolness, and the energy used in watts.)

A fourth principle of dark sky lighting entails controlling the duration of time for which our lights would be used. Much of this control can be accomplished through automated means. Motion sensors and timers can help ensure that the lights only come on when someone comes within a certain distance of the sensor, or at a time of our choosing, rather than running for an indefinite period of time. Of course, these lights would turn off as soon as the person has moved out of range of the motion detector, or when the light’s preset time-limit expires.

Finally, we can help produce darker skies by taking care to select warm outdoor light sources for our homes. Bulbs that operate at Kelvin ratings higher than 3000 generally emit blue or cool white light. These colors of light are known contributors to light pollution and have a greater chance of disrupting the natural cycles of people, plants and animals, than warmer light. A bulb with a Kelvin rating of 2700 (or less) is usually a better choice for residential landscapes and, consequently, a better choice for our environment.

According to ScienceMag.org, roughly 83% of all of the people in the world live in areas affected by light pollution. And, approximately 80% of people living in Canada and the U.S. alone can no longer see the Milky Way, because of atmospheric brightening by artificial light. But, by applying dark sky lighting principles, we can reverse these conditions and their effects. For a comprehensive look at the ways in which you can alter your landscape lighting to protect the environment, visit Darksky.org.

I hope you’ve found this article informative. Please feel free to peruse the rest of the website for more information on landscape lighting.

How to Write an Introduction for a Compare and Contrast Essay

So, our instructor just assigned a compare and contrast essay and we want to know, “How do I write the introduction for a compare and contrast paper?”

A helpful trick to writing a compare and contrast essay is making a list. In fact, we’ll need to make two lists for the similarities and differences related to the actions, objects, persons, or ideas that we are comparing and contrasting. An addition of sufficient background information will help us give readers a good sense of the issue we are addressing. And we’ll also want to draft a thesis statement that helps us focus the attention of the essay. In this article, we will talk more about each of these aspects to help us write a solid introduction for a compare and contrast essay.

Making Lists

A) Make two lists. One will contain the similarities that exist between the items that we are comparing. The other will display the differences. For instance, if we are comparing and contrasting apples and oranges, one list will include the similarities between apples and oranges. Another list will contain the differences between them. A little research of the items we are comparing and contrasting will be useful here, as it can help us find a wealth of similarities and differences.

Example:

Similarities Between Apples and Oranges

1) Apples and oranges are fruit Apples and oranges are round 

2) Apples and oranges are sweet Apples and oranges have seeds

3) Apples and oranges have vitamin C

4) Apples and oranges have potassium Apples and oranges have protein Apples and oranges have folate Apples and oranges have fiber

Differences Between Apples and Oranges

1) Oranges have peals

2) Apples come in more than one color

3) The skin of an apple is smooth

4) The skin (peal) and flesh of oranges are one color (orange)

5) Apples have less vitamin C than oranges

6) Apples have less potassium than oranges Apples have less protein than oranges Apples have less folate than oranges Apples have more fiber than oranges

 B) If possible, we should categorize the items that appear on our lists. This will help us write a thesis statement later in the introduction. The key here, will be to group as many items on the list into a few relevant categories.

Take our similarities list, for example. We can organize its items into four categories: food type, appearance, taste, and contents. In a thesis statement, the mention of these categories, instead of the several items on the list, allows us to refer to these items in a way that makes the thesis statement more digestible.

Example:

Some of the items on the similarities list correspond to physical attributes of apples and oranges (fruits, round, and seeds). The same is true for the first four items on the differences list. Accordingly, we can group these items into a category that we’ll call physical attributes.

Likewise, the similarities list contains the word sweet. Though we have no other items on the lists corresponding to this facet of apples and oranges, we can still categorize the term under the heading, taste. This may prove useful if we think of relevant items to add to the category later.

The remaining items on the similarities list refer to nutrients that also correspond to points of difference between apples and oranges. Accordingly, we can call this category nutrients. So, altogether we have three categories:

1) Physical attributes 

2) Taste

3) Nutrients

Background Information

Once we have a good list of items, and a few categories into which we can group them, we’ll want to consider how our categorized items relate to each other beyond a simple practice of comparing and contrasting them. This allows us to move from merely reporting on an issue to demonstrating its importance to our readers.

Usually, the background information provided in an introduction helps to familiarize readers with a certain topic. However, it can also help create a degree of urgency that prompts the audience to do something with the information. These two points, in turn, crafts an aura of importance that draws readers’ attentions while helping them to gain a general understanding of our topic.

Of course, to provide the kind of background information that informs and creates a sense of importance, it will be useful to choose an arguable topic that is of considerable importance. If we think of fruit in terms of health and healthy eating habits, then we may have an idea that can take us beyond the practice of comparing and contrasting for its own sake. 

A more specific version of this idea that will allow us to contextualize our categories for an essay is the question of how visual appearances influence children’s likelihood to eat healthy food, like apples and oranges. With this added context, we find that we have a few building blocks for our thesis statement: three categories for our lists, a topic that allows us to compare and contrast items, and the means to contextualize our comparison as an important issue.

Background information would, of course, require some research. In our case, this research would focus on gathering information about the effects of the appearance of fruit, children’s eating habits, the effects of apples and oranges on children’s health, etc. Once we have completed that research, we would summarize the findings. For the sake of expediency, I have selected three sources. (Of course, you will want to read more sources to get a firmer understanding of the issue.)

The sources that I have chosen are:

1) “Appearance alteration of fruits and vegetables to increase their appeal to and consumption by school-age children: A pilot study” by Louisa Ming Yan Chung1 and Shirley Siu Ming Fong

2) “The Effects of a Visually Appealing and Interactive Snack Activity on Fruit and Vegetable Intake ofPreschool-Aged Children” by Kristen Leigh Clay

3) “Nutrition Faceoff: Apples vs. Oranges” by Sofia Layarda, RD

In order to use these articles in the introduction, we must organize the information they provide into a summary. This will allow us to put the information in our own words, while condensing it into a size suitable for an introduction.

Example:

An apple never falls far from the tree, so it has some distance to roll to improve our children’s eating habits. As research has demonstrated, significant percentages of children do not get the amount of fruit that they need, preferring less healthy snacks that can lead to obesity and other health issues. However, a few studies suggest that interactive activities and changes in the visual appearance of fruit can help increase children’s daily intake. The differences in children’s preferences for particular fruits are also a factor, because so many kinds of fruit have different types and amounts of nutrients. These conditions make it important to determine which kinds of fruit are most, or least, likely to benefit from the interactive activities and visual changes that encourage healthier eating.

This kind of background information would frame an essay in terms of children’s health, while allowing us to proceed with a comparison between apples and oranges.

Thesis Statement

The thesis statement should accomplish three tasks in a comparison essay. It should 1) use the context provided by the background information to 2) foreground the central theme of the essay, 3) which will be evidenced by the three categories we developed. Listing the categories in the thesis statement helps to ground the thesis in the central theme of the essay. In so doing, it organizes the essay into digestible, logical parts that allow readers to move smoothly through a well-constructed argument.

Example:

Despite children’s preference for apples, oranges are better candidates for interactive activities and changes in visual appearance that are designed to increase fruit intake and children’s health, given the fruit’s physical attributes, tastes, and nutrients.

Benefits

Sometimes an instructor will provide specific boundaries for a compare and contrast essay. As an example, s/he may assign this kind of essay for William Shakespeare’s Hamlet and Othello, asking you to compare and contrast the theme of betrayal as it appears in both plays. In this case, the focus on betrayal narrows the scope of your examination of Hamlet and Othello, allowing you to uncover the intricacies of one element of the two plays, instead of several.

A compare and contrast essay gives us practice with in-depth critical thinking, a process that allows us to uncover obvious, and not so obvious, connections between a variety of the text’s ideas and its methods of presenting these ideas. Through close readings of an article, book, poem, short story, etc., we can develop a keener sense of a text’s nuances and become much more observant readers and dexterous thinkers in the process.

Tools For Installing a Low-voltage Landscape Lighting System

Installing landscape lighting can be an involved process. And, as you might expect, it requires a long list of tools to do the job correctly. For this reason, we’ll be using the space of two articles to discuss the kinds of tools we need to install low-voltage landscape lighting at our homes.

There are several tools that will be useful for installing low-voltage landscape lighting. These include a shovel, wood screws, a screwdriver, wire cutters, a tape measurer, power drills, a voltage tester, lag shields, and a number of others. As you can see, we’re looking at a long list of equipment. So, we’ll get started explaining the significance of each tool.

Shovel (or Flat Spade)

While solar-powered fixtures are not very difficult to place around your home, installing lighting that requires wiring can be a more involved process. And if you’re running wire for outdoor lighting, you’ll probably end up running it underground. Here’s where a shovel will come in handy.

Low-voltage outdoor lighting that requires wiring will also require the use of a transformer. While some people mount the unit to their house, this could mean doing some damage to your home from screwing it in. Instead, you can use a shovel to dig a hole for a wooden post, where you would mount the transformer. For this option, the hole should be about 18 inches deep, with the post extending 12 inches above ground. Placed flush against the house, the post will protect your siding from damage by providing a solid surface into which you can screw the unit.

You can also use a shovel to dig trenches, for hiding the wire where necessary. As a quick note, you might want one-inch wide trenches that are roughly five inches deep. The short width will allow the wire to fit snugly in the trench and cause minimal, reparable damage to your lawn. The depth will protect the wire from regular yard work, playing children, etc.

If you are digging a trench for galvanized piping in order to run your wire underneath the driveway, or the walkway to your porch, you might make the trench approximately five inches wide. In this case, you’d only dig deep enough to get underneath the cement or asphalt of your driveway or walkway. To create a bed around your trees and bushes, in preparation for lighting them with up-lighting, you would dig a trench about three inches deep, enough to get underneath the roots of your grass. You’d also want the bed wide enough to give your lighting the space to point at the tree or bush as opposed to sitting beneath them.

Wood Screws

Wood screws are useful for mounting the aforementioned transformer to your wooden post. You can drill them into a wooden piece and withdraw them without significantly weakening the integrity of the wood. And, as opposed to nails, the torque of wood screws can join two pieces together firmly, turning them into a sturdy unit, despite the presence of any gaps or warping in the wood.

Power Drills and Screwdrivers

A power drill is best for securely mounting a transformer to a wooden post. This is partly because of the ability of power drills to provide the kind of speed that increases torque, allowing for a firm mount. The power and speed of a drill also allows you to insert the screw into the post quickly and more easily, compared with a screwdriver, given the density of the wood.

This is not to say that one should not use a screwdriver while installing landscape lighting. Some light fixtures require some assemblage and a screwdriver may be the best tool for the job. This can also be the case with light fixtures that are not made of sturdier materials. To avoid cracking a fixture, it may be best to insert a screw manually, using a screwdriver.

Tape Measurer

In order to use your wiring efficiently, you may want to know how much of it you need to light various areas and objects around the front and/or backyard. More specifically, you’ll want to know the total distance of your landscape design, from the spot where you will mount the transformer to the furthest light fixture, to help you determine what size you’ll need for a transformer. For this task, a tape measurer is always a good tool to have.

You can opt for the manual tape measurer, if you prefer. Or, you can go with the measurer app on your phone (if your phone has this app). I prefer a manual tape measurer, because I have yet to get the hang of the app, but either one is fine as long as it gives you an accurate measurement. While measuring, you may want to measure out a little more wire than you need, to give yourself some slack in case it becomes necessary.

Electrical Safety Gloves

Although you do not necessarily have to use gloves for digging trenches and measuring distances, it is a good idea to use them when you begin working with wires. For this particular task, your choice of gloves is very important. There are gloves designed specifically for electrical work and, although they can be a little difficult to get used to, they will lower the risk of an electric shock.

Electrical safety gloves are made of rubber and are classified according to the maximum amount of voltage that they can insulate your hands against. (They are also classified by their ability to resist ozone.) The classifications range from Class 00 to Class 4, for a total of six classes. And each class of gloves carries a clear marking of its particular class on the cuff of the gloves.

When you are choosing electrical safety gloves, you want to be careful to pick a pair appropriate for the amount of voltage that will power your landscape lighting system. To determine how much voltage that is, you would want to measure the length of your landscape lighting design to help you calculate the right sized transformer. If your lighting system is running at 500V AC/750V DC or less, then Class 00 gloves is a safe choice. Additionally, you should wear a leather protector over a rubber glove to cut down the chances of the glove sustaining damage that will allow electrical currents inside.

Wire Cutter

When you’re installing the wiring for your landscape lighting system, you’ll end up cutting off some of the wire’s sheathing in order to connect the light fixtures to power. A wire cutter will serve you well here. The process of connecting wires will entail cutting about an inch of the rubber sheathing from the end of the wire, exposing the metal that conducts electricity from the power source. Be careful not to cut the metal itself. You would also cut the sheathing from your light fixture’s wire (if it has not already been done) and then twist the two metal leads together. After joining the leads, you would cap them off with an underground wire connector.

Underground Wire Connectors

Wire connectors are used to maintain the connection between two newly joined wires and to guard against the risk of electrical shock or fire that comes with leaving the wire’s conductive metal exposed. A wire connector’s exterior is usually made of plastic, while the inside contains a metal spring that aids the fluency of the wires’ electrical currents inside the connector. Wire connectors also tend to be color-coded, indicating a variety of sizes and electrical capacities.

Because you’ll be running wires underground, underground wire connectors are the best option for landscape lighting. They keep moisture away from the joined wires and cut down on corrosion, by means of a silicone sealant. Effectively, these connectors will protect your wire, and your lighting, from the effects of rain or a sprinkler system.

Voltage Tester

Voltage testers can help determine whether there is power running through a device, conduit, or source of power. Some voltage testers are capable of displaying the amount of voltage on a digital screen. Perhaps the safest testers are the non-contact variety, called inductance testers. Unlike two-pronged testers, you only need to touch the tip of the tester to a device, conduit, or source of electricity to discover whether there is live voltage. Other testers may require you to come in contact with carriers of electrical currents, making them less safe than inductance testers.

Lag Shields

If you decide to affix a transformer to your house, particularly if it is a brick house, you might consider using a lag shield for the job. Lag shields require the use of a hammer drill and lag screws. The hammer drill can be used to drill an entry hole for the lag screw and to clean out all of the debris, so that the screw can slide into place. Because there are certain specifications for meeting code, you will want to pay attention to the diameter of the hole that you make and the diameter of the screw that goes into it.

As we mentioned above, this list represents only some of the equipment necessary for beautifying your home with an array of well-placed light fixtures. In an upcoming article, we’ll go over the finer points of designing your lighting landscape to maximize fewer fixtures, while reducing the amount of cable you need for an efficient install. For a continuing discussion of the rest of our comprehensive list of installation tools, click here.