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!