Ask Dr. Tina

Turn on the lights!!

2008-02-10T22:08:00.001-05:00

Today's question has to do with electricity. Specifically, how does the light switch turn the light on and off? Well, electricity travels through the wires inside the walls of the house. Imagine that the wires in the house are a highway, with lots of lanes for the cars to drive on. The cars are the electrons, or the charged particles that make up electricity (they are also the things that shock you).

When the light is on, that is like the cars moving smoothly on the highway. The electrons are moving through the wires and get to the lightbulb to make it bright. Now, when the lightswitch is turned off, that's like when a drawbridge goes up. The cars cannot move since the drawbridge is up. When you turn the lightswitch on, it's like the drawbridge closes, and the cars can drive smoothly again.

A lightswitch dimmer works differently. When you use a dimmer to make the light darker, it's as if you were making the highway narrower, so that there are fewer lanes for the cars to drive on. Then there are fewer cars that can pass at any time - meaning there are fewer electrons that can get to the lightbulb when you use a dimmer. When you make the lights bright again, that's when the highway has all its lanes back, and all the cars can get to where they need to go.

Begin at the Beginning - How did life start?

2008-01-21T21:20:00.000-05:00

I find it fitting that the very first question for Ask Dr. Tina is the essential question - How did life start? Scientists believe that life on Earth started about a billion years ago. When the earth was very young, it was very hot. It was so hot that the oceans didn't even exist. Eventually, the earth began to cool down, and water cooled from steam into liquid, which eventually form the oceans.

In the oceans were all the elements, small molecules and atoms, that were needed for life to begin. This is called the primordial soup. When the right conditions occurred, the molecules in the soup reacted with each other to form amino acids. Amino acids are the building blocks of proteins, which are necessary for life. Soon, proteins, fats, RNA and DNA would form and come together into cells. These first cells were the first kind of life, which could divide and make more cells. Eventually, the single celled organisms would evolve into multicelled organisms. These multicelled organisms would continue to evolve and change over millions and millions of years.

Over the millions of years many different types of creatures evolved, like dinosaurs, wooly mammoths, apes, birds, reptiles, and even human beings, until we finally have the world we have today.

Welcome!

2008-01-21T15:51:00.000-05:00

Welcome home, Nicky! I hope that you are ready to have your science questions answered. I will try my very best to answer whatever you ask me. You are free to ask any science question you like, and to follow-up on any response that I give you. Answers are only the beginning. You only ever stop learning if you run out of questions.
More than anything, I hope that I can make this fun, and give you some food for thought so that you can ask your next question and keep exploring.