Save $$$ at the Pump

As gas approaches $4 per gallon, we are all looking for ways to save. Lots of advice is circulating around, but which tips will actually save fuel? Let’s separate fact from fiction:


Fact: Slow down.

Why? There’s this little problem of air and drag. As you zoom down the road at high speeds, your car pushes lots of air ahead of it and leaves a “hole” in the air behind it. The difference in air pressure creates suction that tries to pull your car backwards. At highway speeds, your car uses about 40% of its energy to push the air around, so try to leave your lead foot at home.

Fiction: Pump your gas in the morning.

Why not? The theory behind this myth: cooler temperatures make the fuel denser so you pump more gas molecules in every gallon. However, gas is stored in an underground tank whose temperature varies very little throughout the day, so the temperature of the air really has little effect on the temperature and density of the fuel.

Fact: Keep your tires inflated.

Why? Underinflated tires mean more tire surface on the road, thus more friction. Keeping your tires inflated will not make a huge difference in your fuel costs, but every little bit helps, right?

Fiction: Change your air filter.

Why not? You should replace your air filter regularly, but not because it will save money at the pump. The computer sensors in modern cars adjust the fuel-air mixture continually. A dirty air filter will not cause your car to burn more gas, but it will decrease your engine power. In other words, your car will be somewhat sluggish, sort of like you might feel on Monday morning.

Fact: Jack rabbit starts waste gas.

Why? Think about it; your car probably weighs about 2 tons. The amount of energy to accelerate 2 tons from a stop is considerable, so city traffic will cost you a lot of fuel. Take it easy on starts and stops; in other words, don’t drive like a maniac. Your savings could be as much as 30%!

Fiction: Use premium fuel.

Why not? Let’s say you recently bought the sports car you always wanted, and the owner’s manual says “premium fuel recommended.” Uh-oh, premium fuel is expensive! Will you get better gas mileage with premium? Will you harm your engine with regular? The answer is probably “no” to both. Your gas mileage probably will not be affected, and your engine sensors should detect the lower octane and adjust the timing. However, if your new car says “premium fuel required”, you had better fork over the extra for premium gas.

Fact/Fiction: Turn off your air conditioner.

OK, I am being wishy-washy. The answer here depends on your speed. In the city, running the A/C will cost you more, but on the highway, running the A/C will actually save fuel. There is no question that the A/C uses a lot of your engine’s power, so turning it off whenever you can is a good idea. However, open windows create drag which increases the faster you go. So opening the windows at highway speeds will create enough drag to cancel out the savings. Generally, at speeds over 45 mph, you can justify using the A/C. As you might imagine, windows closed with the A/C off is the best option, but that would be a mite unpleasant on a hot August afternoon.

Happy driving!

Celebrate Earth Day

This Earth Day, I could pass along “green” tips on how to save energy and reduce your carbon footprint, but I will save that for another time. Instead, let me make a suggestion: go OUTSIDE this weekend! Take your dog for a walk, plant a vegetable garden, play outdoor games with your children, visit a local park, take a hike and look for wildlife, or just sit in the sun and appreciate its warmth (with appropriate sunscreen, of course).


If you are a bit more ambitious, visit an Earth Day Festival near you – the Richmond Earth Day Festival will be held Saturday, April 23 in the New Manchester District on the south end of the 14th Street Bridge. Streets will be blocked off and filled with artists, vendors, farmers and fun activities for all ages.

You could also visit the Science Museum of Virginia and explore the energy exhibits, such as New Energy Virginia, Watt Wall, Virginia Tech Solar House and others. When you are ready to get off your feet, enjoy a breathtaking film in the IMAX Dome. And don’t forget the popcorn!

Happy Earth Day, y’all!

What one degree will do...

If you lowered the thermostat on your water heater by one degree this year, you could save enough energy to microwave 207 bags of popcorn or power a fish tank for 19 days.

If 1000 people joined you, we could power 10 homes for 30 days or power a hospital for 4 days.

More energy facts at the Energy Generator:
http://www.willyoujoinus.com/usingenergywisely/energygenerator/?gclid=CKOi6rTRjagCFcPd4AodWDCxDQ

Question of the Week

Gas prices are on the rise again...  The world's supply of fossil fuel is limited and will eventually be exhausted.  Production is becoming more difficult and more expensive.  Many Americans are turning to renewable energy.  What exactly is renewable energy?  Can you name 5 renewable energy sources?

Answer:  Renewable energy is energy that comes from resources that are naturally replenished.  Sources of renewable energy are:  sunlight, wind, geothermal, tides, biomass, and hydroelectricity.

Understanding Japan’s Nuclear Crisis



This image made available from Tokyo Electric Power Co.
 via Kyodo News, shows the damaged No. 4 unit of the
Fukushima Dai-ichi nuclear complex in Okumamachi,
 northeastern Japan, on March 15, 2011.
 White smoke billows from the No. 3 unit.
Credit: AP Photo/Tokyo Electric Power Co. via Kyodo News

By Harrison Mebane
Physics graduate student
University of Illinois

In the aftermath of the devastating earthquake and tsunami in Japan, the world is watching an unfolding crisis in Japan’s Fukushima nuclear reactors. Below is an attempt to explain the science behind the crisis to the best of our knowledge. Not a nuclear expert myself, I asked my son, a Physics graduate student at the University of Illinois. Yesterday he attended a seminar on campus where professors explained what we currently know about the situation. Here’s his report.


In order to understand what's going on, you need a good image of what the reactor looks like.  Here is a good picture: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiq21FyAV0CFRADII8Pwe2SWfPFybLnk1Wg5V1qjtm97uxOU0y7GlJhH4NVeJA6KDgpsIuTva6-fWDX1e-S34tjP0FTOsKix1KXXPdbMseYiVyVYKvVqY6Fz2gCwmHRx5ws2ddsnBiRCdw/s1600/BoilingWaterReactorDesign_3.jpg. 

This type of reactor is called a boiling water reactor. The reddish cylinder in the middle is the reactor core. Inside are fuel rods, which are zirconium clad tubes filled with uranium pellets. The fuel rods are surrounded with water being pumped in from outside. The water serves two purposes in this type of reactor: it is a coolant, and it slows down neutrons so that they are more easily absorbed by the uranium (it is called a moderator in this context). The problem at the Fukushima reactors occurred when power was lost. When power is lost, the reactor automatically shuts down (control rods are inserted, which stops the sustained reaction). Water has to be actively pumped into the reactor to cool it. Without power, the water circulation stops. The Fukushima reactors had multiple diesel generators on-hand, but the tsunami appears to have knocked all of them out. They had backup battery power, but it didn't last long. Once power was lost, the water in the reactor just sat there and began to boil off. The core remains hot long after the reaction has stopped because the fuel still contains a lot of radioactive material which will continue to decay. That is the main issue right now. If they could guarantee a constant safe water level in all of the reactor cores, the problem would be solved. They are currently pumping in seawater (which will ruin the reactors, but they aren't worried about that), but this is difficult because the core is under such high pressure. They need very strong pumps to get water in.

Now, the big news lately has been these explosions. To the best of anyone's knowledge, these were hydrogen explosions. It is not at all obvious where the hydrogen comes from, since it is not a decay product. It comes from the fact that steam can react with the fuel rods' zirconium cladding to create zirconium oxide (in effect, it rusts). Steam normally does not come in contact with the zirconium but it did in this case because the water level sank below the tops of the fuel rods (this is what the media means when they say the fuel rods were "exposed"). As oxygen is leached off of the steam molecules in the formation of zirconium oxide, hydrogen is produced. At some point, the pressure of the steam became dangerously high and had to be vented. It was vented out of the core and then out of the primary containment vessel (labeled in the diagram) into the secondary containment vessel. This is where the explosions occurred. Interestingly, the steel plates surrounding the secondary containment vessel are "meant" to be blown off in the case of an explosion. If they were on too tightly, an explosion might damage the primary containment vessel, and that would be bad. So that's exactly what happened in all of the explosions. You can see the steel skeleton in pictures of the exploded reactors.

Now, one major concern at this point is the spent fuel ponds. You can see one of these in the image; it is the pool of water just to the right of the core containing rectangular slabs. These slabs are spent fuel. The spent fuel is put in this pool to cool off after most of its uranium-235 has reacted. It stays hot for a long time, though, so it is kept in the pool until it is cool enough to move to a secure location. After the explosions, you can see that the spent fuel pond is exposed to the outside. That's fine as long as there is water in there to absorb/block radiation. The fear is that either a) the water will boil off, or b) the pools were damaged in the explosions (or the fire a couple days ago) and could be leaking. The more worrisome scenario is situation b. If the water level drops enough, the spent fuel will no longer be cooled effectively, and it may begin to melt. If it gets hot enough to ignite, the fire would send large amounts of radiation into the air. That is what happened at Chernobyl, though at Chernobyl the core itself caught fire, so it was much worse. It is unclear how secure the spent fuel ponds are at this point.

During the last two days there have been significant radiation spikes which have forced personnel to leave temporarily. During these spikes, the radiation was high enough to cause radiation poisoning in an hour or two. Nobody knows the source of the radiation. There has been some speculation that it was due to a leak in the suppression pool, which is the torus below the primary containment structure in the picture. This torus is full of water and is meant to relieve pressure in the primary containment vessel if it gets too high (maybe when they released pressure into the secondary containment structure, the suppression pool wasn't taking enough pressure away, or maybe they just wanted to vent off the hydrogen). At this point the suppression pool has been in contact with radioactive material, so a leak in it would result in possible leakage into the environment. Again, this is just speculation at this point, and it is unclear how much, if any, leakage has occurred.

Question of the Week

Suppose you are going on vacation and want to save on your heating bill.  Which will save more - turning off your heat completely (assuming your pipes won't freeze) or just setting the thermostat to a lower temperature?

In other words, does it cost more to heat the house up from a very cold temperature than it would to keep it at a more moderate temperature while you are gone?

Answer:  Turn off your heat! Based on years of research, the US Department of Energy concluded "the fuel required to reheat a building to a comfortable temperature is roughly equal to the fuel saved as the building drops to a lower temperature. You save fuel between the time that the temperature stabilizes at the lower level and the next time the heat is needed." In other words, during the period your house is at its coldest temperature, you are saving on your fuel bill. So if you aren't worried about your water pipes, pets or tender houseplants, turn off the heat while you are away. Not only will you save on your fuel bill, but you will also conserve valuable natural resources.

Energy
What would have to happen for energy not to be a bigger and bigger focal point in our lives? The world’s population continues to grow, now projected to hit 9 billion by 2050. (It sometimes seems like the bulk of this commutes in from Short Pump on many weekdays.) The standard of living expectations for more and more of us continue to go higher. If residents of developing nations have access to "CSI: Fort Wayne, Indiana" showing improved living conditions around the world, why shouldn’t they also aspire to this quality of life? (Where’s my roomy family sedan to park in my two-car garage next to my oversized house in the suburbs with big-screen TV located 35 miles from my place of work?)

That’s just the demand side of the equation, what about the supply? The primary sources of power used by residents of Planet Earth are fossil fuels. Aptly named, these energy sources have a finite supply that is based — in large part — on stuff that died several hundred million years ago. At some point, we will inevitably run out of these carbon-based fuels; we can argue over when, but there is no argument over if.

So, more people clamoring for more energy and less of it to go around. What do we do? Panic? Of course not, it’s science time. Right here at the Science Museum of Virginia, we have wonderful examples of part of the solution to the problems, such as:
· A sleek, smartly designed and very upscale solar house developed by Virginia Tech in our parking lot. (I can speak from personal experience as to how cool the house is, since I lived in it for my first two months on the job.)
· A real working windmill
· A geothermal system
· Several types of photovoltaic cells that collect energy from your favorite K class star
Stay tuned. As this issue becomes a bigger part of our lives, we will be expanding on our interpretation of it at the museum.