Water and cornstarch make a non-Newtonian fluid when mixed: messy but great fun!

Fast-forward fifteen years to the beginning of the present school year and the Internet has given us all a huge leg-up in finding hands-on ways to learn science. These are demonstrations rather than experiments–an important difference for those entering a fair. Nevertheless, I have included two of my favorites below.

Homemade Oobleck:

Pay tribute to Dr. Seuss's book Bartholomew and the Oobleck by whipping up this mixture that is both solid and liquid at the same time! The simplest version is listed below, but adding a few more bells and whistles can increase the demonstration's awe-factor a bunch.

What to do: You need a mixing bowl, water, and cornstarch. Fill the mixing bowl with about 1 cup of cornstarch, and add roughly an equal volume of water. Mix, incrementally adding cornstarch or water until the mixture attains an appropriate blend of goopiness and firmness. Enjoy the fluid's bizarre properties by squishing and kneading it with your hands.

What's going on? Nearly all fluids have some intrinsic flow resistance. This property, called viscosity, is the reason water flows more easily than honey and at least partly why Usain Bolt can run 100 meters in under 10 seconds while it takes Michael Phelps well over a minute to swim the same distance. Our water/cornstarch mixture has a very special viscosity, making it easy to dip your hand into the mixture slowly, but quite hard to push it in quickly. (Technically, this is an example of a non-Newtonian fluid.) Science class will teach you that almost all matter can be classified into either a solid, liquid, or gas, but this is at least one example where the distinctions blur.

Bernoulli's Hair Dryer:

In 1738 the mathematician Daniel Bernoulli (pronounced Ber-NEW-lee) published a theory of fluids that has influenced the designs of airplane wings and sailboats ever since. Exploit this concept to suspend a balloon or ping-pong ball precariously in mid-air with a hair dryer.

What to do: You need a hair dryer and a small round balloon (or a ping-pong ball, depending on the hair dryer's strength). Turn the hair dryer on, point it upward, and place the balloon in the vertical column of air. If the ceiling is not too high, you should be able to balance the balloon in mid-air this way. Now begin to tilt the hair dryer and watch the balloon stay suspended almost magically.

What's going on? Everyday experience helps us understand why the balloon or ball stays suspended when the hair dryer is pointed vertically: air blowing upward pushes on the balloon, and this in turn counteracts gravity. But why doesn't the balloon fall off to the side when we begin to tilt the hair dryer? The answer lies in Bernoulli's principle, which states that, all other things being equal, a fluid loses pressure as it picks up speed. The air coming out of the hair dryer is moving faster than the room's air so its pressure is lower. This pressure difference helps keep the balloon suspended, even when you tilt the hair dryer.

Water and cornstarch make a non-Newtonian fluid when mixed: messy but great fun!

How much air is your house leaking? Are you unknowingly slurping in dirty air from your garage and attic? Perhaps a blower door test can help you find out.

"I went to the ServiceMagic Web site that I learned about editing a Home Energy article," says Tom. "Within less than a minute after I entered some basic information about my house and what I was looking for in the way of an energy audit, the phone rang." It was Sustainable Spaces, a home performance contractor located in San Francisco. Tom made an appointment for his audit for the next week. "They were offering a 'Stimulus Special' for $395."

The house Tom shares with his partner Dmitri was built in 1907. "The home has never been remodeled," says Tom. "We recently had the furnace replaced with a hot water radiant system. We have been careful to keep to the original features of the home, so we got our radiators from buildings built around the same time that used to be part of the heating systems in buildings at Fort Baker." They also installed a renewable energy source. "We installed photovoltaic (PV) panels on our roof, but we should have had the audit first to show us how to use less energy and save on the PV.  Our annual true-up statement says we owe $75 for electricity, but I want to get that down to $0!"

Rob Mitchell, an experienced contractor who knows a lot about Bay Area houses, came with two younger men for an audit of Tom and Dmitri's 102-year-old home. The crew closed all the exterior doors and windows, installed a "blower door" in the main doorframe, and depressurized the house. Immediately, dust and insulation particles began to pour through the "pocket doors" from the attic. After taking some measurements to get a general sense of how leaky the house is, and blocking some of the major air leaks, the crew from Sustainable Spaces then pressurized the house. "We walked around the house with a liquid pencil, which showed there is airflow around switch plates, gaps in the baseboard where the home is connected to the outside, and the cabinet in our kitchen where there used to be 'torpedo tubes,' which used to hold hot water heated by the wood stove, and other places" says Tom.

So the old house has some problems with air leakage, which means heating energy being lost to the outside. The crew also found out that the humidity in the kitchen was 20% higher than that on the outside of the house. "We both took showers that morning, and I had a cup of hot tea," says Tom. That was enough to keep the humidity high a few hours later.

Since the home has no mechanical ventilation, moisture build up could lead to mold growth on surfaces in the living spaces, or-even worse because it is hidden-within the walls. Mold can degrade building materials and create poor indoor air quality. Tom has allergies and a moldy house could make it difficult for him to breathe. Since Tom is living in the mild climate of the Bay Area, where we can open windows and get fresh air other ways in our leaky houses, the moisture may not hang around long enough to be a problem. If he lived in a cold climate such as Minnesota's, or a hot-humid climate such as Atlanta's, fixing the air leaks in his house without adding mechanical ventilation could create a "sick house", meaning one with poor indoor air quality due to mold.

"We won't get the report until next week," says Tom. The report will include specific numbers for air leakage from the house to the outside-or in this case between the living spaces and the attic and basement. Too much air flow means lost energy and too little means a sick house. The report will also give a range of measures that will make Tom and Dmitri's house healthier and more energy efficient. "We'll decide what measures we want done when we get the report. We made our heating system more efficient with the radiant system that heats the living spaces and provides us with hot water. We use half the gas now to heat water than we did before. So spending a lot more on fixing the building envelope doesn't make so much sense to us right now. We'll probably fix the big leaks by air sealing around the attic. And we may insulate under the floor between the living spaces and the basement."

"I wanted to have our house audited mostly because I'm curious," says Tom. "And we want to save energy." But from now on when Tom talks about home performance, and the importance of healthy and efficient homes, it will take on a whole new dimension-the homeowner's perspective.

This attic hatch insulation kit install is making the author use some choice language.

I promised Michele that I will practice the Yoga of home improvement projects and keep the cursing down to a minimum. My home improvement projects usually involve some cursing. I worked part time as a janitor when I was in high school and that's when I learned some pretty spicy language. I didn't intend to write about cursing here, but since I am in this so deep now, then damn it, I may as well connect the topic to some cutting edge scientific research. You got a problem with that?

British scientists found that cursing takes away pain. When people put their hands in a tub of cold water and cursed, they could hold their hands in longer than if they said things like, "butterscotch." If you don't want to take my word for it, you no-good so-and-sos, the research results were published in the online journal NeuroReport.

The attic hatch insulation kit will save us some energy losses and utility bill pain in the long run. According to the DOE Weatherization Assistance program, a gosh darn uninsulated 10 square foot attic hatch in a 100 square foot insulated attic can decrease the overall R-value of the attic floor by more than 50%! For example, an attic with R-38 insulation everywhere but on top of a stinking quarter-inch plywood hatch-with an R-value of approximately 0.3-will have an overall R-value of only R-17. What a freaking waste! Bloody hell!
You can find out more about insulating attic hatches at the Department of Energy's Energy Efficiency and Renewable Energy Web site. Do it now!

Non-profits like Green For All are working with federal and state goverments to usher in new "weatherization worker" legislation.

Tuesday, July 21

There are 3,200 people here for the conference in Indianapolis! This is more than twice as many as the last time. Heard from Gil Sperling, Program Manager for the Department of Energy’s Weatherization Assistance Program, and others at opening plenary. Some buzz about Davis-Bacon prevailing wage legislation. Department of Labor created a new category "weatherization worker" and is polling organizations around the country to come up with prevailing wage numbers. Department of Labor staff is here to get feedback.

Five U.S. Territories are now part of the Weatherization network.

Van Jones speaking at lunch today.

Will set up display for later today. Something like 94 exhibitors are here, including heavy hitters like Home Depot and Sears. Will try to convince Home Depot folks to carry Home Energy Magazine in stores.

(later)

Van Jones, White House green jobs czar, spoke to weatherization workers at the National Weatherization Training Conference, "You are the quiet heroes. Your job is to take the inhalers out of little girls' pockets; little boys pockets."

No, he is not encouraging shoplifting, but the kind of homes that do not aggravate kid's asthma. A green home is an energy efficient and healthy one. That's something the weatherization community has known since the DOE Weatherization Assistance Program began in 1976.

Wednesday, July 22

At the awards lunch today, Gil Sperling mentioned that the Dept. of Labor (DOL) is making good progress in discussions with local weatherization agencies to determine the prevailing wage for a new classification of worker, the weatherization worker. The Davis-Bacon legislation from a decade ago (?) requires that organizations receiving federal government project money must hire people at the prevailing wage for similar work in the area. The legislation is being applied to the funds coming through the American Recovery and Reinvestment Act (ARRA) of 2009, (also known as the Stimulus Bill) for weatherization efforts. DOL came up with a new classification of worker, weatherization worker, in order to help the states comply with the Davis-Bacon requirements.

If the prevailing wages of construction workers were the standard, in New York, beginning weatherization workers would have to make $50 per hour! Weatherization agencies all over the country want to pay their workers well, but those kind of wages for beginning workers would wreck the budgets of most of them. So the new classification and prevailing wages will help agencies to pay a living wage, increase pay as workers become more experienced, and allow the agencies to live within their budgets. DOL staff are here in Indianapolis, and there listening sessions have been packed!

Thursday, July 23

A friend asked me What is the headline for the conference? I think it should be Weatherization Gets Down to Business. I am reminded of the ramp-up to the war in Iraq, and the war profiteering that is probably still going on. I remembered the “lost” $8-billion in the first months of the war. And I wonder if that kind of corruption will enter in the “war for energy security and green jobs and against global warming.” It probably will, because humans are involved. But the level of accountability here is very very high, and the expectations are very very clear. And I get the sense that, this time, the adults are in charge.

Are you using Twitter or other social media as a way to promote progressive causes like energy efficiency? What do you think about mandatory home energy audits or line drying clothes versus machine drying? Source image: Tina Keller

Now I get my information mostly off the Internet and through Twitter, the social media service that is in the news because of its use by the opposition parties in Iran. Twitter is like snail mail cubed. You send messages from your computer or smart phone that immediately show up on the computers or phones of all your "followers." You get followers generally by following others. It's kind of an unwritten rule that if someone is following you should return the favor. So far I am following about 30 people or groups and have 11 followers. But I just started.

I am following Energy Circle, a new Internet resource that is using social media to report news about home energy efficiency on Twitter. A recent "tweet" connected me to an article by Peggy in Toronto who thinks that mandatory home inspections should be replaced with mandatory energy audits upon the time of sale of a home. Advanced Energy's Research Director Melissa Malkin-Weber, tweeted "Energy saving smugness nixes scratchiness of air dried sheets. But don't ask my kids about how those stiff cloth diapers felt."

I agree with Peggie and Melissa. But what do you think about mandatory home energy audits or line drying clothes versus machine drying? Are you using social media as a way to promote progressive causes like energy efficiency? You can respond below, and your response needn't be limited, like "tweets" are, to 140 characters. Or sign up for a Twitter account and join the conversation at KQED Science!

This is a LEED-certified building on Columbus Circle
in New York City. Anything wrong with this picture?

But there is some question as to whether LEED buildings actually save energy. Henry Gifford, an engineer and mechanical system designer in New York City, "…the best data available shows that on average, they (LEED-certified buildings) use more energy than comparable buildings." His view is controversial, but I have seen the data he used and have studied his analysis and it seems reasonable to me, though I am not a statistician and have done a limited amount of number crunching in my short career as an engineer before becoming a writer.

I have heard the arguments from the other side and haven't been convinced. Even from a common sense perspective, it seams unrealistic that LEED buildings are built to save energy. I've seen too many LEED certified buildings with a large percentage of windows as exterior walls–that is like trying to build an energy efficient building without walls. Also, LEED certification does not require performance testing of buildings. A building can achieve points for energy efficiency from modeling alone. In my role as editor of Home Energy Magazine, I have wanted to publish in-depth articles about LEED-certified homes, but I have been unable to find a LEED-certified building owner or designer who is willing to publish a full year of performance data, post-occupancy.

The LEED program has made green building a common term and a sought after designation among architects, builders, and developers across the nation. LEED buildings may use more environmentally friendly materials and be healthier for their occupants. But it is not yet clear to me that they save energy compared to business as usual. If we want to achieve energy independence, combat the worst effects of global warming, and grow a green economy, we can't afford to build–and celebrate–buildings built as usual.

Dave Robinson is the "anti-flipper." Credit: Tom White

The cab driver is a renter, and when I told him that the conference he was driving me to was about residential energy efficiency, health, sustainability, and affordability, he complained that his landlord is not interested in making his rental home energy efficient, since the landlord doesn't pay the energy bills. We call this a split incentive. The split incentive facing the imaginary bankers in the back seat of my driver's cab-he wants to keep the bailout money for himself but he's supposed to use it to help people struggling in a down economy-may not end up putting a fat wallet in the cabbies back seat.

I met a man here who can handle a split incentive pretty well. David Robinson is a retired contractor who recently started doing what he calls Energy-Wise Renovations of foreclosed homes. He is buying clusters of homes in rundown neighborhoods in the South Bay, and retrofitting them with measures such as R-50 insulation in the attics, air sealing, and Energy Star appliances. But he is also creating some pretty stylish kitchens, redoing hardwood floors, and installing granite countertops, crown molding, and wainscoting in these homes. "You can't sell a home on energy efficiency alone," says Robinson.

Robinson is having no problem selling these houses for 20% above market prices, and he's still giving the homebuyers, and the neighborhood, a very good deal. "I believe that there is a wonderful and huge opportunity in bank-owned foreclosures-millions of them-and we must rescue all those wonderful opportunities from the normal house flippers who would turn them into a rental and lower the values and miss the opportunity for deep energy reduction. I buy all foreclosed homes and don't feel bad about beating up the bank to get the really good deals."

Robinson is looking for former or current realtors, and financial backers. He wants to teach them his method and therefore accelerate the process of converting our housing stock to affordable, efficient, and sustainable housing, and to make a good living doing so. If you want to know more, call him at (605) 475-4800.

Stanley Jevons first described the take back effect in 1865, so this is nothing new. Jevons observed that new efficient steam engines decreased coal consumption, which led to a drop in coal prices. But the lower prices meant that more people could afford to use coal, and so coal consumption increased.

The "Snackwell Effect" takes it's meaning from the habit of people on diets who eat lots of low-cal snacks that add up to many times the calories of a regular snack. The example given in both articles mentioned above is a West Virginia couple that bought an energy efficient washing machine to replace their old inefficient one. Their energy bills were no different after the conversion. Turns out they were doing more loads of laundry, even washing one piece of clothing in one load, because they were lulled into complacency by their energy efficient purchase.

I asked Jim McMahon, the head of the Energy Analysis Program at Lawrence Berkeley National Laboratory (LBNL), about the Snackwell Effect and appliance energy use. I recently heard him speak about the great efficiency gains made between the first energy crisis brought on by the Arab oil embargo in 1973, and today. Those gains are significant; refrigerators today use about half the energy on average than they did in the 1970s. "This effect [Snackwell Effect] has been studied for a long time, [it was] formerly called the rebound or take back effect," he says. One 2001 study concluded that for every gain in energy efficiency, about 10% is taken back by an increase in energy use. Greater air conditioner efficiency, for example, may mean that people lower their thermostats, since they expect their energy bills to be lower, and this eats into the efficiency savings. "I think that there are a number of energy-using devices where consumers do not exhibit the Snackwell effect, such as refrigerators or televisions. In those cases, in my view, the usage behaviors are unrelated to the cost of energy, at least for most households in the United States," says McMahon. He does admit that more study is needed in this area. A 10% take back effect is significant, but certainly not a barrier to serious energy efficiency improvements.

Karen Ehrhardt-Martinez, a sociologist, studies human behavior and energy use for the American Council for an Energy Efficient Economy (ACEEE). "The relationship between energy efficiency and energy consumption is not as straightforward as it may initially appear and as some people like to portray it."

The trends show that: 1) residential energy consumption increased by roughly 57% between 1970 and 2005; and 2) residential energy consumption per capita increased by only 7%".

According to Ehrhardt-Martinez, a bigger problem than the 10% of energy lost due to the take-back effect-or the Snackwell Effect-is the proliferation of energy using, albeit more efficient, devices in American homes; lifestyle choices, such as the dramatic increase in the size of homes while families got smaller; population increase; and the "invisible" energy, such as standby power or phantom loads, that is hidden from consumers. "However," says Erhardt-Martinez "if we were able to combine efficiency improvements with better lifestyle choices (i.e. smaller, more energy efficient houses), smart purchasing behaviors, and improved information mechanisms that allowed consumer to actively manage their energy consumption, then we could have a much more dramatic impact on both household level consumption as well as state and national level consumption."