Stories tagged sunlight

Another danger associated with alcoholic beverages. Be careful not to store your vodka bottles in the way of direct sunlight. Or get ready to call the fire department.


Picture this with more balls: Nice, huh?
Picture this with more balls: Nice, huh?Courtesy Echo_29
Southern California is ball-crazy! Sure, everyone loves balls, from babies to seniors, but SoCal has brought it to a whole new level.

Los Angeles, in particular, is doing things with balls I’d never even thought of. They’re putting them in the water… by the millions! Millions of balls in the water, I guess, will make it better to drink.

The issue here is cancer. Or carcinogens—materials that can cause cancer. So the issue here is cancer.

Bromide, a naturally occurring ion of the element bromine, happens to be found in Los Angeles’ reservoirs. Bromine isn’t much to worry about on its own, but it turns out that the ion interacts with chlorine and sunlight (both of which are also found in the LA reservoirs) to form bromates, a group of chemicals that contain carcinogens. I couldn’t find a reference that explains it fully, but it looks like this is how it (basically) works: chlorine dioxide, the form of chlorine we use to treat drinking water, breaks down in sunlight into chlorine and oxygen. The bromide ions end up grabbing on to some oxygen to form BrO3, the bromate anion (“anion” just means that it’s a molecule with a negative charge). When that negatively charged bromate anion combines with a positively charged ion, a bromate is formed. And those are, as we’ve established, often bad. The combination of sunlight, bromide, and chlorine in LA’s reservoirs means that their water sources are becoming contaminated with bromates.

So thank goodness for balls, lots of balls. The Los Angeles Department of Water and Power means to solve the problem by removing sunlight from the situation. In about five years a huge underground reservoir should be finished, but until then LA has decided that the best way to block sunlight from the water is to cover it with millions and millions of black, plastic balls. They’ll float, and allow most things, but not sunlight, to pass through them. And they’ll look super crazy.

As we all know, however, you don’t just fill up a couple 10-acre reservoirs with balls in a weekend. Plus, the ball-making company can only produce about 100,000 balls a day, and there’s no doubt a great demand for balls beyond LADWP’s 6.5 million ball order. So this going to be a lengthy project. Over the next four years the Ivanhoe and Elysian reservoirs will be filled with about 3 million balls each. And then the underground reservoir will be ready. I expect there may be some spare balls around LA at that point.

Here’s more on the trouble with Bromates in drinking water.

And here’s more on balls.


The big D: Research continues to shed light on the role vitamin D plays in our bodies.
The big D: Research continues to shed light on the role vitamin D plays in our bodies.Courtesy Leo Reynolds

We've talked beforeon Science Buzz about the link between sunlight, vitamin D and cancer. Well, the story just won't go away...

Here's more evidence that sunlight = vitamin D = a healthier life.

And research that shows vitamin D can reduce the risk of diabetes.

And also reduce risk of a heart attack.

But, just to keep things balanced, here's a report that vitamin D doesn’t do everything – some of the health benefits claimed for the vitamin don’t stand up to research

And here’s a summary of the pros and cons of vitamin D and sun exposure.


Sun, sun, Mr. golden sun.: Sunlight has both positive and negative effects on the body.  Sure is pretty, though, ain't it?  Photo by S4N7Y from

Sunlight is good for you! It helps your body produce vitamin D. And lots of us could use more vitamin D.

Sunlight is bad for you! Overexposure to ultraviolet light can lead to skin cancer.

Sunlight is good for you! A new study shows that vitamin D helps prevent breast cancer.

Sunlight is a myth! It hasn’t stopped raining here in over a week.


Sunlight helps the body produce vitamin D, which seems to prevent some cancers: Photo by sooz from

For years, doctors have advised people to limit their time in the sun. Prolonged exposure to sunlight – specifically, the UV rays in sunlight – damages skin and can lead to premature aging and skin cancer.

But now, a new report claims that lack of sunlight can lead to cancer, too. A study found that people with low levels of vitamin D have higher rates of cancer. And the body produces vitamin D naturally when skin is exposed to sunlight.

So, going out and getting some sun may actually prevent more cases of cancer than it causes.


Here are some more random questions we've received from visitors to our website or our exhibits.

Q: Why is the Earth round? I thought it was flat.

A: Nope, the Earth is round. Not perfectly round, though. Planets like Earth are round due to gravity. Gravity pulls with equal strength in all directions, so gravity shapes the planet into a sphere. But, since the Earth rotates, the rotation adds centrifugal effects, which result in the Earth bulging slightly at the equator and flatten slightly at its poles.
Because of these centrifugal effects, the distance from the center of the earth to the surface of the earth is about 0.33% shorter at the poles compared to the equator.

Q: How does gravity work?

A: Gravity is one of the universal forces of nature, and is the tendency of objects with mass to accelerate toward each other. Newton's law of universal gravitation states that each particle of matter attracts every other particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

More simply, everything that has mass has gravity, and the larger the mass, the stronger the gravity. Earth has stronger gravity than the moon because the mass of the Earth is greater than the mass of the moon.

Q: What is zero gravity?

A: Lots of gravity related questions! Zero gravity, or weightlessness, is best termed microgravity. Astronauts floating in space are not actually weightless, or in zero gravity, because the Earth's gravity is holding them and everything in the spaceship they are in, in orbit. They are actually in a state of free-fall, much like jumping from an airplane except that you are moving so fast horizontally that, as you fall, you never touch the ground because the Earth curves away from you.

Think about it this way. Considering what we learned about gravity above, if you stood on a bathroom scale and then somehow opened some trap doors that dropped both you (still standing on the scale) and the scale out of a plane, both you and the scale would be pulled down equally by gravity. You would not push down on the scale and therefore, your weight would read zero.

Q: Why is the sky blue?

A: Sunlight is scattered across the Earth's atmosphere by a process called "diffused sky radiation". The sky is blue because much more short-wave radiation (blue light) is scattered across the sky than long-wave radiation (red light). Check out this website that explains more about this, and also why the sky appears red during sunsets.

Q: How come the Science Museum you only teach one side of the story? What I mean by this is that not everyone believes in evolution, and you only talk about that side of the story. Why don't you have exhibits on theories other than evolution such as intelligent design?

A: It's in our name. We're The Science Museum of Minnesota. We represent and teach science in our exhibits and programs. We're not saying that there are not other ideas or beliefs out there (intelligent design is not a scientific theory, rather a religious belief), and we respect others and their beliefs. However, as an organization that teaches science, we practice and encourage the teaching of evolution as fundamental to the teaching of sound science and critical thinking. If we were to compromise the scientific explanations of evolution or permitted unscientific alternative explanations into our exhibits or our programs, we would be misrepresenting the principles of science. Here is the Science Museum of Minnesota's official position on evolution.

Q: Do you like pie?

A: Yes. I especially like Key Lime pie.