Thursday, February 3, 2011

Paper Chromatography



Chromatography is a method for analyzing complex mixtures (such as ink) by separating them into the chemicals from which they are made. Chromatography is used to separate and identify all sorts of substances in police work. Drugs from narcotics to aspirin can be identified in urine and blood samples, often with the aid of chromatography.



You Will Need:

Water
Rubbing alcohol
Stapler
Pencil
Coffee filter (or filter paper)
Water soluble food colors
Water-soluble marking pens,
Clear glasses or other containers

1. Cut several coffee filters into long strips, one strip per pen.
2. Fold the end of each strip over then staple it to form a loop.
3. Place a dot of ink near the bottom of each strip. Use a pencil to identify which strip belongs to which pen.

4. Poke a pencil through one of the loops you just made. Use the pencil to suspend the strip in a small glass or container.
5. Carefully add water to the glass until it reaches the bottom of the paper strip just below the ink dot. Be sure the ink stays above the water and the paper stays in the water.


6. Allow the water to soak up the strip and watch what happens to the ink drop.
7. If the ink you are testing does not spread out, re-test it using rubbing alcohol.
8. Repeat this process for each strip and compare your results.
9. Let the strips dry and tape them on a sheet of paper as a record of the different pen types.
10. Observe.

SCIENCE BEHIND THE EXPERIMENT
Because molecules in ink and other mixtures have different characteristics (such as size and solubility), they travel at different speeds when pulled along a piece of paper by a solvent (in this case, water). For example, black ink contains several colours. When the water flows through a word written in black, the molecules of each one of the colours behave differently, resulting in a sort of “rainbow” effect.

Many common inks are water soluble and spread apart into the component dyes using water as a solvent. If the ink you are testing does not spread out using water, it may be “permanent” ink. In such cases, you will have to use a different solvent such as rubbing alcohol.

Wednesday, February 2, 2011

Whirling Color Wheel


In art, color is very important. The color wheel is often used to explain the relationship of different colors to one another. In this way, artists know what colors look good with each other, and how to mix paint to produce more colors. All possible color combinations can be made by mixing just three primary colors with white and black. Artists use a color wheel that has the three primary colors - red, yellow, and blue - and three secondary colors - orange, green, and violet - as well as the tertiary colors that are in between, such as blue-green.

In this project, see the bright colors of the rainbow disappear right in front of your eyes, as you learn about the properties of light and how we see color.

What You'll Need:
- a pencil, scissors, white cardboard or heavy white paper
crayons or markers, a ruler
- a small bowl or a large cup (3 - 4 inch, or 7 - 10 cm diameter rim)
- a paper cup

1. Use the bowl to trace a circle onto a piece of white cardboard and cut it out. With the ruler, divide it into six approximately equal sections.
2. Color the six sections with the colors of the spectrum as shown at the figure below. Try to color as smoothly and evenly as possible.
3. Poke a hole through the middle of the circle and push the pencil part of the way through.
4. Poke a hole in the bottom of the paper cup, a little bit larger than the diameter of the pencil. Turn the cup upside down on a piece of paper, and put the pencil through so the point rests on the paper on a table. Adjust the color wheel's position on the pencil so that it is about 1/2 inch (1 - 2 cm) above the cup.
5. Spin the pencil quickly and observe the color wheel. Adjust as necessary so that the pencil and wheel spin easily.


SCIENCE BEHIND THE EXPERIMENT
The colors on the wheel are the main colors in white light. When the wheel spins fast enough, the colors all appear to blend together, and the wheel looks white. Try experimenting with different color combinations.

Tornado Simulation


Tornadoes as we know it are mad gigantic, funnels of spiraling doom that would bring about a gusty havoc into our town's and city. Now it's time to see how these funnels are made and how can we make them
For your future storm chaser, you can create vortices with your very own tornado experiment for kids. What's great is that the tornado maker is so easy. Even you at home can do it.



You Will Need

* Two empty two liter bottles.
* Water to fill one bottle about 2/3 full.
* About a teaspoon of dish washing detergent (this makes the simulated tornado behave a little more realistically.

Some people also like to add the following, but they are optional and won't affect the outcome of the experiment:

* Food coloring makes a very interesting presentation.
* Glitter to simulate debris.
* Gorilla tape (if you can't find any, duct tape will do.)

Take one two liter bottle and fill it about two thirds the way with water. Add a teaspoon of dish washing detergent. This helps make the speed and behavior of the vortex, a little more like the real thing.

You may also want to add food coloring, Monopoly houses, or glitter to watch what happens to the debris in a tornado.

Placing the other two liter bottle directly on top of the two litter bottled that is filled with water, place gorilla tape around the bottle necks so that they are standing end to end. From experience, I highly recommend taping the bottles together very, very securely. They should not be able to move from side to side, but rather when you handle them, they should feel like one bottle. I cannot emphasize the need to tape thoroughly enough!

Give it a good twist or turn it end to end and see what happens.



SCIENCE BEHIND THE EXPERIMENT
If you watch the funnel as it is formed and wiggles around you are seeing a simulated tornado. If you happened to simulate any type of debris in your bottle (such as Monopoly houses) this little vortex sucks them up just as it would suck up real debris.
Like a real tornado, what you've created is a vortex. When air begins to spin very rapidly, it creates a vacuum in the middle. If you've ever watched water drain from a bathtub, you'll note that the center is empty while the water around it is spinning rapidly. This is also known sometimes as the "eye".
If you watch the news when there's a major hurricane, you'll hear lots of talk about the "eye" and the "eye wall". The eye of the storm is the calmest part while the wall of the eye is the deadliest, spinning the most rapidly.

Fireproof Balloon



Balloons are rather fragile things. You know that they must be kept away from sharp objects. They also need to be kept away from flames. A fire can weaken the rubber and cause it to burst. However, in this experiment you will find out how you can hold a balloon directly in a flame without breaking the balloon.


For this homemade science experiment you will need:

* two round balloons, not inflated
* several matches
* water

Inflate one of the balloons and tie it closed. Place 60 milliliters (¼ cup) of water in the other balloon, and then inflate it and tie it shut.

Light a match and hold it under the first balloon (A). Allow the flame to touch the balloon. What happens? The balloon breaks, perhaps even before the flame touches it.

Light another match. Hold it directly under the water in the second balloon (B). Allow the flame to touch the balloon. What happens with this balloon? The balloon doesn't break. You may even see a black patch of soot form on the outside of the balloon above the flame.



Why does the balloon with no water break in the flame? The flame heats whatever is placed in it. It heats the rubber of both balloons. The rubber of the balloon without water becomes so hot, that it becomes too weak to resist the pressure of the air inside the balloon.

How does the balloon with water in it resist breaking in the flame? When water inside the balloon is placed in the flame, the water absorbs most of the heat from the flame. Then, the rubber of the balloon does not become very hot. Because the rubber does not become hot, it does not weaken, and the balloon does not break.

SCIENCE BEHIND THE HOMEMADE SCIENCE EXPERIMENT

Water is a particularly good absorber of heat. It takes a lot of heat to change the temperature of water. It takes ten times as much heat to raise the temperature of 1 gram of water by 1C than it does to raise the temperature of 1 gram of iron by the same amount. This is why it takes so long to bring a teakettle of water to the boil. On the other hand, when water cools, it releases a great deal of heat. This is why areas near oceans or other large bodies of water do not get as cold in winter as areas at the same latitude further inland.

CAUTION: Be careful when handling matches to avoid burning yourself or causing accidental fires.

Check out some more homemade science experiment here..

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