Careful observation is a very important part of science. Ornithologists learn to identify birds from a quick glimpse as they fly through the trees. Meteorologists learn to read the clouds in much the same way that most people read books. Geologists learn to look at a hillside covered with gravel, and spot the one piece that happens to be a fragment of dinosaur bone. Part of this is learning what to look for, but part is also training your eyes to really see all the details that are there. To give this a try yourself, you will need:

• several chocolate chip, oatmeal raisin, or other cookies. Homemade are tastier, but you can use store bought cookies too.
• paper to draw on
• pen, pencil, crayons, or something else to draw with.
• a ruler

Pick two cookies at random. Eat one. Place the other on the table in front of you. Look at the cookie. I mean, REALLY look at it. Imagine that you are going to have to look at a pile of similar cookies, and know this one well enough to pick it out of the pile.

Draw a picture of your cookie, being sure to note any identifying marks. Maybe one of the chocolate chips has a crack in it, or there may be two raisins at the edge that almost touch each other. Don't worry if your drawing is not perfect. You are recording your observations, so as long as it shows the things that make your cookie special, it is a wonderful drawing.

Measure your cookie, noting on your drawing any measurements that could help identify it. Maybe one side is thicker than the other, or it may be 1/4 inch wider at the point where the two raisins almost touch. Again, pretend that you need to record your cookie well enough to pick it out of a lineup of other cookies.

Once that is done, put your cookie in with all the others. Close your eyes and have someone mix them well. If you are doing this on your own, close your eyes and shuffle them well. Then open your eyes, and find your cookie. Check it against your drawing and measurements to be sure that it is your cookie.

How well did you do? If you want to make it a bit more challenging, try using cookies that are manufactured to be very similar. Oreos work very well for this. They all seem to look alike, but if you look carefully, you can spot irregularities in the filling, top cookies that are not exactly aligned with the bottom, and other small differences.

Want to make it a bit more challenging? Ask someone else to look at your drawing and notes, to see if they can identify your cookie. This takes more practice and skill, but it is a skill well worth learning.

Once you are done, you will have a pile of cookies that have been handled. That means that you can't put them back in the package, so dispose of them properly. I like mine dipped in either milk or hot tea.

The more you practice observation, the more you will see in the world around you. You can do this activity with other objects, such as pennies, rocks, leaves, or sticks, but in that case, skip the step where you eat one.

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Three Holes, part 2

Hopefully, you spent quite a bit of time thinking about last week's experiment, and more importantly, performing the experiment to see if you were correct. If not, before you read any more, GO TRY IT! If you don't, you are missing out on the actual fun of scientific investigation. This week, you will need:

- the same materials that we used in part 1.
- 3 more bottles
- some wooden blocks or other things to change the height of the bottles

If you did try it, you probably got results similar to what you see in the photo below.

If you did try it, you found that the water stream from the middle hole hit at the greatest distance from the bottle. Why? To understand that, we need to look at the variables involved with each of the three streams.

Variable? What is that? It is something that can change from one test to another. If we think of the three holes as three different tests, then the variables are the things that change from one to another.

The first variable is the water pressure, and that varies according to the depth of the water. The deeper the water, the greater the pressure. That means that the top hole will have the least water pressure, and the bottom hole will have the greatest water pressure. Then why didn't the bottom stream go the farthest? Because there is another variable involved.

What else is different for each stream, besides the water pressure? The distance that they have to fall to hit the surface! If that distance is too short, the stream when it could still travel much further from the bottle. The top stream has a longer distance to fall, giving it a longer time to move away from the bottle. The bottom stream has the shortest distance to fall, so it has the least time to move away from the bottle.

Looking at the three streams, the bottom one has the most water pressure, but not very far to fall before it hits the surface. The top stream has the least water pressure, but a long way to go before it hits. The middle stream has more pressure than the top, and more distance to fall than the bottom. That combination lets it hit the farthest from the bottle.

Is there a way that we can compare those variables? Easy! All we have to do is to control one of those variables.

Which will go farther?

You could control the water pressure by using three bottles that each had a hole at the same depth. By placing the bottles on top of blocks, you could arrange them so that the three streams were at different heights. With the same pressure for each, the highest stream would go farther, since it has the longest time to travel away from the bottle before it hits the surface.

Which will go farther this time?

You could control the distance the water has to fall by using three bottles again, but this time, make a hole near the bottom of one, near the middle of the second, and near the top of the third. Then place them on blocks so that the three streams are all the same distance from the surface. This time, the stream with the most water pressure (nearest the bottom of the bottle) will go farther.

From there, you can gradually change the height of the blocks until all three bottles were the same height. That would bring you back to where we started, with the middle stream reaching the farthest. With careful testing, you would probably find that the maximum distance would not be at exactly the middle of the bottle, since one variable may make a larger difference than the other. If one is causing more difference, which do you think it is? You'll have to try it yourself to find out.

Have a wonder-filled week.

Three Holes
This week's experiment will give you some good practice at thinking scientifically. The experiment itself is very simple, but as with many simple things, the more you think about it, the more you will see. To try this, you will need: - a two liter soft drink bottle - pliers - a sharp nail - water First you need to empty the two liter bottle. I highly recommend using the soda to experiment with making the perfect ice cream float. Once the bottle is empty, rinse it and remove the plastic label if it has one.
We want to make three holes in the plastic bottle, each at a different depth. Holding the nail with the pliers, make a small hole about one inch up from the bottom of the bottle. I found that twisting the nail back and forth as you push makes it easier to start the hole. You want the hole to be round and as smooth as possible. Be careful not to tear the plastic (or your skin!) Once you make the hole, wiggle the nail around a bit to help make the hole round.
After you make the first hole, make the second about half way up the bottle, and slightly to one side. You want all three holes to be as close to the same size as possible, and you do not want the holes to be directly above each other. The third hole should be about an inch or so below the point where the top of the bottle starts to narrow, and again a little to one side. The photo on the right shows approximate locations.
Place the bottle in the sink, under the faucet. Fill the bottle with water, and leave the water flowing just enough to keep the bottle full as the water flows out of the three holes. We want to compare how far each stream of water goes, which is why we did not want one hole directly above another. We want to be able to see the three streams easily. Now you should understand why we are working in the sink, to keep from making a mess.

Before you actually try this experiment, take some time to think about it. Once the bottle is full, water will be flowing out of all three holes. If you measured how far each stream of water moved away from the bottle before it hit the bottom of the sink, which stream of water would hit the farthest away? Which stream would hit the closest? Why? Keep in mind that there may be more than one thing to consider in how far the water reaches.

Once you have spent enough time thinking to have a good idea of what will happen, turn on the water and try it yourself. Next week, we will look at the results, and figure out why it worked the way it did.

Have a wonder-filled week!

Go to Part 2.

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The Smell of Money

A magic trick that can teach about observation and the senses.

We are used to thinking of things as falling into the basic groups of solids, liquids, and gases. (In another experiment we will discuss a fourth state of matter, plasma.) In this experiment, we will examine a substance that sometimes acts like a solid and at other times acts like a liquid.

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Have you ever seen a random dot stereogram? You see them on posters, cards, calendars, etc? It can be a random pattern of dots or a repeated pattern of just about anything, and if you stare at it in just the right way you suddenly see a 3 dimensional image sticking out of the page. Have you ever wondered how they are made? Lets take a look.

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Sometimes the right answer is not the only answer.

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Which will go out first, the tall candle or the short one?

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The answer to the last video's challenge.

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How does mass relate to pitch?

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Well, it is December, which means that I am rereading one of my favorite science books, Michael Faraday's "A Chemical History of a Candle." Faraday was a marvelous teacher, and his lectures were amazing. Sticking with the candle idea, we will take a close look at how they burn. You will need:

- a candle
- a match or lighter to light the candle
- a candle holder

Since we are using fire, be sure to get permission, and be sure that there is an adult there , so you have someone to blame in case something goes wrong.

Place the candle in the holder and light it. Now get comfortable and watch the flame for a minute. Take the time to really observe what is happening.

OK, now for the question. What is burning? The candle. OK, but what part of the candle? Your first instinct is probably to say that the wick is burning, but is it? Take another long look, and you will notice that although the flame is coming from the wick, the wick is not burning up. Instead, the wick seems to stay the same length, even as the candle burns shorter and shorter. How can that be?

If the wick is not burning, then what is? The candle wax. Notice that there is a pool of melted wax around the base of the wick. That melted wax soaks up into the wick, just as water soaks up into a paper towel. It is the melted wax, not the wick that is producing the flame.

So, does the wick not burn? If it did not, then as the candle burned shorter and shorter, the wick would stay the height of the original candle. Take another close look at the candle flame. You should notice that the wick is curved, and at the point where it gets close to the outside of the flame, the end of the wick is glowing. In the center of the flame, there is very little oxygen, so the wick does not burn. As the wax burns down, the end of the wick gets near the oxygen rich air at the surface of the flame, so that part burns away. That keeps the wick the same length, as the candle burns lower and lower.

I always look forward to holidays and birthdays, because they are perfect times to pause and enjoy the incredible science involved in the simple act of burning a candle. Yes that is the reason. It has nothing to do with all the pies, and cakes, and cookies, and egg nog, and ice cream, and ..., well, maybe that too, but I definitely enjoy the candles while I am eating.

Have a wonder-filled week.

Learn some of the science behind optical illusions.

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