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July 17, 2008

The Myth of King Mufasa: Lions & Hyenas

Perhaps you've seen the Disney animated movie, The Lion King.

Lions are often made out to be regal, the kings of the African savannah. Hyenas, on the other hand, are made out to be trixy, thieving and sneaky dogs. (Current-day hyenas have more in common with big cats than dogs, you know.)

The truth is not so simple. The truth is, kill-stealing happens all the time in the wild. For survival.

Stalking, chasing, killing, and protecting a kill all takes vital energy from the hunter. It is also not without risk. The hunter has to leave their den (and little ones behind are left alone) and the hunter risks getting hurt in the hunting process, if the prey strikes back.

The cheetah is an excellent example here: she's the fastest predator on the plains, but after her sprint to catch her dinner, she has to catch her breath for several minutes before she even has the energy to EAT. And in those critical moments, her kill could be taken with little effort by another hungry animal.

A kill site in the wild is a complex place, with a progression of animals showing up for their turn. For example:

A pride of lions brings down a cape buffalo.
They eat the parts they like best. The stomach, etc.
Some hyenas show up. The lions, full or outnumbered, back off.
The hyenas eat what lions cannot. Bones included.
The smaller jackals have been watching and waiting.
Eventually, the hyenas get full, too. Too full to chase the jackals.
The jackals are followed by the vultures.
The vultures are followed by other, smaller, hungry mouths.
Finally, the insects take over.
And lastly, the plants benefit from the nutrients of the remains.

It's true that lions don't particularly like hyenas. And hyenas don't particularly like lions. But this is because they are both the top competitors for food in the ecosystem.

Lion and Hyenas At A Kill.  This photograph was taken on my first trip to Africa. Hyenas confronted a single lion over a giraffe kill. The hyenas won out, but they had probably been the ones to take down the giraffe in the first place, since the single lion was sick with TB and likely a rogue scavenger.

Lions routinely steal kills from hyenas. In fact, when we were first in the Kruger in South Africa, several guides told us that hyenas were bringing down more animals, and the lions were the ones stealing the kills. 

They joked: "Lions are lazy. They let the hyenas do all the work."

That progression I illustrated above could just as easily have started with:

A pack of hyenas take down a cape buffalo.
They eat the parts they like.
A bunch of lions show up, full or outnumbered, they back off.
The lions eat the parts they like.
The jackals have been watching...

You get the picture.

Posted by sorsha at 2:05 PM | Comments (3) | TrackBack

Green Gadgets: The Fan, Not AC

This is another article in our "Green Gadgets" column written by Shane Conder, a guest blogger.

This gadget will blow you away.

It's mid-summer. We're sitting in our upstairs office. The humidity is medium-high. It's 80 degrees. My wife asks me to turn off the fan because she's cold. Cold? With an indoor temperature of 80 degrees?

That's right. That's the effect wind chill can have with a simple floor fan. I'm guessing the fan was making her feel like it was in the mid to upper 60s. That's a 12-15 degree difference in feeling. Is that true?

As it turns out, there are multiple things going on. First, wind chill is the apparent cooling of the air temperature as wind passes over your skin and causes faster evaporation from your skin. (As an example, spray a water bottle at your skin with some wind and you'll feel even cooler.) Second, the heat index is the temperature you feel when you combine humidity with the actual air temperature.

Wind chill is basically when the temperature feels lower than it really is and is typically only useful when the real temperature is below 50 degrees Fahrenheit. The heat index is basically when the temperature feels higher than it really is and is typically only useful when the real temperature is above 80 degrees Fahrenheit.

Both measurements can have a dramatic effect on how cold or hot you feel. For instance, with a real temperature of 84 degrees and the relative humidity at 80% it will feel like it's 94 degrees. Likewise with wind chill. If it's really 20 degrees Fahrenheit out and the wind is blowing at only 10 miles per hour it will feel like it's 9 degrees.

So what does this have to do with fans during the summer? If you can run a fan that helps dry the air around you some by more rapidly evaporating and removing liquid from your skin you'll feel cooler for two reasons. The first is from the water evaporation around you. The second is from the drying effect this will ultimately have. The net effect of both is that it will now feel as if it's cooler than the real temperature rather than warmer. I believe this effect goes up as the humidity increases.

The typical measurement found around the web is that running an overhead fan can make an 80 degree room feel as if it was 72 degrees, which is typically considered a comfortable room temperature.

What about the electric cost?  If you don't already have air conditioning, you will be adding a small cost. An overhead fan likely uses between 50 watts and 100 watts, on high. At the worst case, running one 24 hours a day will use 73 kWh in a month. That's a little over $12 a month at our rate of 16 cents per kWh.

That sounds like a lot? Well, compare that to a full house air conditioner. A typical household air conditioner can run at 3500 watts. They won't run all the time, of course, but they will keep the entire house cool-even rooms you aren't using. Calculating the actual expected energy use of an air conditioner is actually quite complex. We'll simplify by assuming it can keep your house cool by running for 8 hours each day. Insulation and outside temperature will affect this number. However, if we assume that, the air conditioner will cost about $136 per month at 16 cents per kWh.

It's also said that raising the thermostat from 72 degrees to 78 degrees in the summer can lower the energy consumption by 10 to 20%. At these rates, this would save us $13-$27 per month. That's enough to pay for two fans running all the time! We don't have an air conditioner, though, and our warmest room on our top floor rarely goes above 85 degrees. Our floor fan, though is very powerful and creates a strong wind that makes even 95 degrees feel quite comfortable. It's cost? 300 watts. At 8 hours per day, and our energy costs, that's under $12/month. Still far, far cheaper than running an air conditioner.

Still too expensive? There are some solar powered desk and floor fans available, such as this fan and clock combo. A pure solar powered fan likely won't be as powerful as a floor fan or overhead fan, but it might be enough for one person at a desk.

Try out of a fan. You really may be blown away by how comfortable you feel with it on.

Posted by shane at 11:13 AM | Comments (0) | TrackBack

July 15, 2008

Green Gadgets: Water Powered?

This is another article in our "Green Gadgets" column written by Shane Conder, a guest blogger.

Recently, I happened across a type of gadget I had not yet heard about: a water-powered clock. Intrigued, I found the company who makes it, Bedol, and read about it. Sure enough, you just pour in some water and, if needed, a touch of salt, and it'll power the clock.

The use of water for power, although eco-friendly on it's own, isn't the end of this story.  From what I can tell, another selling point of these clocks is that they don't have the bad chemicals found in battery (and some solar) models. The water-powered clocks also appear to have fewer parts than crank-powered models. This means the clocks are likely pretty eco-friendly compared to a similar battery or solar powered variant.

Since I haven't heard of this type of powered gadget before, I decided to search around for more. I found quite a few clocks and calculators that are powered by just water. I found a clock at Think Geek, a calculator at Amazon, another clock at Lehman's, a different calculator at X-treme geek, and one of each at Ambient Weather. There were other varieties around the web, but I didn't find any other small, electric gadgets that were water powered. I am still looking, though.

It's clear that you can't power much this way. Small clocks and basic calculators use very little power to operate. Many are already solar powered.  However, a water powered version may actually contain better components and, thus, be more eco-friendly overall. I'll have to see if I can find out more information about this.

Posted by shane at 12:43 PM | Comments (0) | TrackBack

July 14, 2008

Green Gadgets: Calculating Electricity Cost

This is another article in our "Green Gadgets" column written by Shane Conder, a guest blogger.

In our last article on the Kill a Watt, we talked about using it to measure how much power your devices are using. Now we are going to talk about how to use that information to calculate the costs of operating your devices. It doesn't matter now if you use a Kill a Watt or something else that will tell you how many kilowatt-hours or current watts an appliance uses.

There are multiple ways to calculate the cost of using a device. One method is to use your current bill to find the total cost for a month and then divide that by the total kilowatt-hours (kWh) listed on the bill. This will give you an average cost per kilowatt-hour. For instance, if you had a $91.20 bill and used 480 kWh, your current average price per kilowatt-hour is 19 cents ($91.20/480). Now, taking that value, you can then multiply it by the number of kilowatt-hours that a particular device uses.  The example we used last time was a 100 watt light bulb, which will add 0.1 kWh every hour to your bill, so we now know that every hour that this device was on 1.9 cents was added to your bill.

This method is useful if your electricity is billed at a flat rate. It is also useful to see an average of how much each device you currently use is costing you.  In New Hampshire, we have an electric bill that is always charged at just about 16 cents per kilowatt-hour (cheap, from our point of view).

In California, though, we had a tiered rate (you're charged different rates depending on how much you've used - California charges higher rates the more power you use in order to reduce power consumption). Simply, your rate starts low, but if you went over a certain limit, you get charged at higher rates for the additional use. This had interesting ramifications, because your power bill might normally be charged at the low rate until you bought a new appliance, which added enough power consumption to your bill to bump you into a higher rate. Kind of like taxes. 

In California, our peak tier was 33 cents per kilowatt-hour. If our bill was over about $85 per month, additional use would fall into the peak tier at the highest rates. This means that any new appliance we plugged in or additional power we used was billed at 33 cents per kilowatt hour, not at the average rate from the previous bill. This is a very important distinction. Again, adding a device in a tier rate billing environment will add a cost at the most expensive tier you pay at and maybe even the next tier up. In the above example, this means if we had added the 100 watt light bulb, we would be adding 3.3 cents per hour of cost. When compared to the 1.9 cents average from the previous bill, our calculations would have been wrong by nearly 75%!

Now for a couple of examples: If you pay 16 cents per kilowatt-hour flat rate and you add an appliance that will be on all the time and uses 250 watts of power, how much will it cost?  An average month contains about 730.5 hours (see the tip at the bottom for an easier way to do these calculations). Multiplying 16 cents by 0.25 kWh by 730.5 hours/month, we see it will cost more than $29 per month or over $350 per year! What if you have a 100 watt porch light that is on for 8 hours each night and we pay 33 cents per kilowatt-hour? That would cost about $8 a month. For a light bulb that costs less than a buck, that's a lot.

If you let your measuring device, such as the Kill a Watt, add up the total for a month you have less calculating to do. Just multiply the kilowatt-hours by the rate. For instance, we left it measuring our TV (with regular use) for a month and saw 73.5 kWh listed. We then just multiply that by 16 cents per kilowatt hour to get a cost of $11.76 for the month.

Another important note is that an appliance plugged in may use power even when it is switched off. Many devices have idle modes or power saving modes. These usually still use some amount of power and it adds up fast. For example, we once measured one of our printers at 21 watts when just sitting idle. At our rate of 16 cents per kilowatt hour, that adds $2.45 a month to our bill. This power use is often referred to as "Standby power" or "Vampire power".

TIP: Did you know you can use Google to quickly calculate the cost of an appliance for a particular time period? You can. I calculated the examples by typing these search terms in to Google: "(16 cents/kWh) * (1 month) * 250 watts", "(16 cents/kWh) * (1 year) * 250 watts", and "(33 cents/kWh) * (1 month * 8 hours/day) * 100 watts" (the capital case of the "W" in "kWh" is critical) (click on the links to see the results). That's basically just the rate per kilowatt-hour, the time period (you can try 1 week or 1 day or 1/2 year, and so on) the appliance will be on for, and the amount of power used. It's fun and easy.

Now that we've learned how to calculate the cost a new appliance will add to our electric bill, we're going to go around our house and measure a bunch of stuff.  We'll then post our findings and see how they compare and we will tell you about any surprises we found (there have already been two!).

Posted by shane at 2:46 PM | Comments (0) | TrackBack

July 12, 2008

Green Gadgets: An Introduction to the Kill A Watt™

This is another article in our "Green Gadgets" column written by Shane Conder, a guest blogger.

Today I'm writing about a gadget you may have already heard about. Have you ever wondered how much electricity something you plug into the outlet really uses? You read on the label the peak power that an appliance might use, but does it use that much power all the time? How much power does something use over a given amount of time when there are variable power requirements?

All of these questions can be answered with a simple and inexpensive gadget called the Kill-A-Watt from P3 International. This device will show a lot of different pieces of information. The pieces we are interested in, though, are the Watt measurement and a sum of the Watt-Hours that the device has measured.

The first measurement, Watts, will tell you how much power is being used by a device in it's current state. For instance, if you were to plug in a lamp that had a 100 watt light bulb in it, the Kill a Watt will likely read 100 watts as these bulbs are usually pretty close to their rated power. What can you do with this? Well, you now know that if you leave this particular device on for one hour it will use that many watt-hours (Wh) of power. In our example here, one hour would result in 100 watt-hours. Your electric company likely measures electricity consumption in kilowatt-hours (kWh). Just divide your watt-hours by 1,000 to get the amount of kilowatt-hours that can be used for calculating costs. In this example, that results in 0.1 kWh for using the lamp for one hour. (Quick science note: Kilowatt-hours is a measurement used by the electric utilities in many countries, including the United States. In your science class, you'll learn that one Watt for one second is a Joule, a more common measurement of power used over time in science. One kWh is 3.6 megajoules. Although it's referred to as power used, it's more accurately the amount of work performed.)

The second measurement on our Kill a Watt shows the actual number of kilowatt-hours (shown as kWHr) of power that has been measured. Since this is already in the units that your electric company probably uses it can be used directly. This number is typically lost when you unplug the basic Kill a Watt. However, some versions will keep this information when they aren't plugged in.

Now you can go around your house and measure the electricity being used by all of your devices. Try it out even when a device is off. You might be surprised at the results! Let us know what you find.

This is the first of a series of articles on power usage. In the next article, we'll talk about how to calculate how much your devices electricity will cost. Then we'll talk about some common devices and how much electricity they use, even when supposedly powered off.

Posted by shane at 10:52 AM | Comments (0) | TrackBack

July 11, 2008

Green Gadgets: Soda-Club Home Soda Makers

This is the second article in our new column, Green Gadgets, written by guest blogger, Shane Conder.

Do you like drinking soda? Do you like drinking sparkling water? Do you hate lugging it home by the case? Do you find your recycling bin fills up quickly with soda cans and water bottles? If you answered yes to any of the above, you might be interested in a home soda maker from Soda-Club.

These devices make great tasting sparkling water (also called fizzy water, or seltzer water) from your own tap water. You simply fill the provided bottle, press the button at the top a few times, and you have ready-to-drink soda water. Add your own flavoring or one of the many flavors Soda-Club provides to make flavored soda water or even soda similar to many big name brands. (Laurie finds the taste of their diet soda very similar, if not better, to that from the name-brand sodas and it still provides the caffeine she wants.)

What's green about this? First, the bottles Soda-Club provides are reusable. That means you have less waste, even if it is recyclable waste. Second, the full cans and bottles don't have to be transported to your store and then to you. Nor do the companies have to truck water and supplies to their factories for you. These costs should not be underestimated.

Speaking of cost, these soda makers can actually reduce your spending on sparkling water and soda. For the initial package, you'll likely spend around $120 to get a kit that can make 220 liters of soda. That comes out to 55 cents per liter. Soda cans have about a third of a liter in them. At 25 cents each, you're already saving 20 cents a liter. Over the course of your first 220 liters, that's $44. Now factor in that you won't need to drive to the store to buy your soda nor will you (nor your trash guy) need to drive your recycling to the recycling center and your savings may be substantially more. That savings is just with the starter kit. 

The incremental cost for your next 220 liters is going to be around $40 to get refill carbonators, which arrive at your doorstep by mail. That's now only 18 cents per liter. At that minor expense, you'll see $125 in additional savings, for a total of $169 in savings over the same quantity of name-brand soda. You've now saved more than you spent on your new soda maker, reduced waste in landfills, and eliminated some fuel used by industrial transportation costs and your own.

(Note: I haven't included the costs of the flavoring syrup or some shipping costs. I've also assumed a price of 75 cents per liter for either sparkling water or canned soda. Your costs may vary.)

These types of soda makers are convenient, quick, cheap, and green. We highly recommend a soda maker of the type Soda-Club sells. We've had one of these for over a year now. We create 3-4 liters a day and have not had any problems.

Posted by shane at 12:37 PM | Comments (0) | TrackBack

July 10, 2008

Green Gadgets: Proper Use of Toilet Paper Rolls

This is the first in a new "column" called Green Gadgets, written by guest blogger, Shane Conder, a tech-blogger.

I've always preferred to have the toilet paper roll with the paper coming over the top away from the wall rather than underneath and now I find an environmental reason to do so. This is the proper way, according to Current Configuration's article "Over is Right, Under is Wrong", to save trees.

The article goes in to the "science" behind this, but basically it breaks down to the tear point is farther back so you're more likely to use more paper. Additionally, when tearing with the paper coming down the back, you're more likely to have the roll spin and lose paper to the floor (who wants to use toilet paper off the bathroom floor?). All of this combined may be minimal savings for you, but multiply it by the billion or so people that have access to toilet paper and it might be substantial.

Posted by shane at 2:14 PM | Comments (0) | TrackBack