What's the difference between a fast and slow metabolism?

I needed to explain to a student in my health class why her friend, despite eating garbage all day never put any weight on meanwhile she had to eat very healthy to stay the way she was. I explained that a metabolism is very much like gas mileage. A fast metabolism is like a Hummer. To drive say 50 miles, you may use about 5 gallons of gas, since it doesn't do a very good job at converting that gas into energy. A slow metabolism is like a Prius, that can go 50 miles with probably about a gallon, making good use of that one gallon of gas.

I said look at the bright side, if this was a million years ago, your friend would have died from starvation while you would be able to chug along with no problem whatsoever! A slow metabolism is a positive evolutionary trait of survival.

I thought water freezes fast in the fridge, why not in the ocean?

A student asked me about why the ocean stays liquid even thought it gets way below freezing during the winter months. "How come snow melts in the water even though it's so cold out?" she said.

Well, water has a much higher specific heat than most land materials. You can go from summer like conditions to winter like conditions in a flash but the water temps will barely change over the same time period. That's because water needs a lot more heat energy to raise its temperature. While land can heat up with only one day's worth of heat energy from the sun, the water needs to collect many day's worth of heat energy to start getting warmer.

Hence why we have colder water temps in the summer while the land is hot and warmer water temps in the winter when the land is cold. See how science helps you to understand things that you may have been confused with?

Why does snow stick on the Grass first?

One of my students asked me why would grass or dirt start to accumulate snow first before other surfaces that have a lighter color. They said that the sidewalk is light gray and yet it has a harder time getting covered with snow than the darker colored soil and grass. Even black cars accumulate faster than pavement!

Well, I explained that even though color does play a role in how hot something gets, what the thing is made of plays an even bigger role when it comes to snow. A black car top will get covered way before a light colored sidewalk because the car top material won;t hold on to heat as well as pavement will. So even though the car is much darker, it will pile up faster because it's able to cool down faster than the cement. I love when kids ask about my favorite weather subject - snow!

I thought the Earth was a star...

What can you say to a statement like that? The best way to take care of this kind of question is to carefully explain what the differences are between a planet and star.

I told the young man that a star has to make it's own light. It's like a big nuclear reactor. "Do you think we could live on a nuclear reactor?" I said, hoping that he would understand that life is not possible to survive on a star. Remember, any pictures of the Earth you've seen from space that are nice and bright is just sunlight reflecting off of it. If you put a flashlight's light beam against a dark room's wall, does it mean that the wall is making it's own light? Of course not.

Do we go around the sun or does the sun go around us? He knew the answer to this question, which helped, because I explained that planets orbit the sun, not the other way around.

Of course, there are many more ways you can show that Earth is a planet and not a star, but these two examples were good enough to show that Earth is planet and nothing more.

For more info on the sun and Earth relationship, check out http://www.youtube.com/watch?v=FjCKwkJfg6Y

Is the Earth Flat?

Hello everyone, and welcome to Science Follies! Here we will discuss different topics in science and misconceptions that go with them. I love clearing up common mistakes about everyday things and ideas. In this blog, I will explain the truth behind the most common misconceptions. Trust me, you'll feel smarter when You're done reading.

My first story will reference an incident that happened to me just today. I was doing a lesson on how we know that Earth is round. Most kids are like, "we have pictures from space!" Obviously, this is the easiest way to prove it. A student of mine, however, asked me if the Earth is flat. You thought I would be flipping out right? How can someone not know the Earth is round!

Well, as shocked as you might think I was when I heard that a student in the year 2009 thought the Earth was flat, I really wasn't that affected by the comment. To tell you the truth, I was almost prepared for a question like that. Every year I teach about the Earth being round I get someone asking me about the flat Earth theory. Well, let me tell you, it never gets easier to explain over the years.

Now there is more than one way to show the Earth is round. So I told the student, "know what a lunar eclipse is?" She tells me of course. Of course! Why wouldn't she know what a lunar eclipse is? I tell her that shape going in front of the moon is round. She agrees. Case closed. Teaching 2,500 year old knowledge never gets old!