Monday, February 16, 2009

Exploring Color: Sharpie Shirts


Everybody loves color! It makes our world incredibly beautiful. Color is what makes rainbows, flowers, and paintings so interesting. Did you know that there is a lot of science in the colors you see around you? In this activity, you will explore the science behind color and create some beautiful artwork along the way.

Here’s What You Need
  • White T-shirt
  • Sharpie® Permanent Markers (Red, Orange, Yellow, Green, Blue, Purple)
  • Rubber Band
  • Large Plastic Cup
  • Dropper Bottle or Medicine Dropper
  • 70% Rubbing Alcohol
Here’s What You Do
Locate the area on your shirt that you want to decorate and place the opening of the cup directly under that section. Secure the t-shirt to the cup by stretching the rubber band over the t-shirt and around the opening of the cup.

Using the Sharpie, create a circular pattern of about six dots (about the size of a quarter) in the center of the stretched out fabric. Using another marker, draw dots in the spaces between the first dots. If you like, you can add a third marker to draw some additional dots. In the picture below, my son, David, has decided to get a bit creative with his design. He has include some lines and squiggles as well.

Slowly squeeze about 20 drops of rubbing alcohol into the center of the circle of dots. Watch as the rubbing alcohol is absorbed into the fabric. What happens? The ink spreads in a circular pattern expanding outward from the center.

Of course, you can draw things other than dots on your t-shirt. Try drawing a small square with each side being a different color, or use primary colors (red, blue, yellow) to draw a geometric shape, and accent it with dots of secondary colors (orange, green, purple). You may want to experiment with shapes like half circles and polygons. You are limited only by your imagination. Here are a couple of things to keep in mind: Keep your patterns small and centered in the design area. Use small drops of rubbing alcohol. Drip the alcohol slowly in the center of the design. This gives the color an opportunity to spread outward from the center.

Allow the developed design to dry for 3 to 5 minutes before moving on to a new area of the shirt. After you finish decorating your shirt, heat set the colors by placing the shirt in the dryer for approximately 15 minutes. You may also want to rinse the shirt in a solution of vinegar and water as a means of setting the colors.

SAFETY NOTE: Rubbing alcohol is very flammable and must be kept away from any open flames or heat. This experiment must be conducted in a well-ventilated area, preferably outdoors or in a room with open windows.

The Science Behind The Colors
In addition to color mixing, this activity also involves the science behind solubility and molecules. Generally, we think of the ink in Sharpie markers as permanent. This means that Sharpie ink will not wash off with water. This is because the molecules in Sharpie ink are insoluble in water. In other words, the molecules don’t mix well with water. However, Sharpie ink is soluble in rubbing alcohol. This means that Sharpie ink will mix with alcohol. In this activity, we use this important piece of information to create very unique designs on a t-shirt. As the alcohol, also known as the solvent, soaks into the t-shirt it carries the molecules of colored ink with it. Since the alcohol spreads outward from the point where it is dropped, it creates a beautiful circular pattern on the shirt.

Wondershop Fast Fact
The Sharpie marker was introduced in 1964. Since then, it has been expanded into a wide product line and multiple colors. As of 2002, 200 million Sharpies had been sold worldwide.

Note: I was first introduced to this activity by Steve Spangler. Steve gives credit to Bob Becker, a chemistry teacher in Kirkwood, Missouri.

Wednesday, February 11, 2009

For Valentine's Day...How About Some Fizzy Bath Salts Science

Valentine's Day is right around the corner, so I thought I would introduce a great science activity that also makes a great gift. With just a few ingredients and a little science, you and your children can create some great smelling, fizzy bath salts. Forget Bath & Body Works. You don't need Bed, Bath & Beyond. You've got science!

Here's What You Need...
  • 1 cup baking soda
  • 1/2 cup corn starch
  • 3/4 cup citric acid (found at many health food shops)
  • 1 cup Epsom Salt
  • 1 cup fine Sea Salt
  • Lavender essential oil (you can use another scent if you like)
  • Food coloring
  • Large mixing bowl
Here’s What You Do
Combine the epsom salt, sea salt, and citric acid in a large mixing bowl. Add a few drops of essential oil and food coloring. If you want a stronger smell or a darker color, you may want to add more. Once the ingredients are mixed and dry, add corn starch and baking soda. It is very important that wait until the first mixture is dry before adding the corn starch and baking soda. Store your mixture in an air tight container. When you are ready for a bath, sprinkle some of the mixture in a tub full of warm water and let the your worries fizz, fizz, fizzzzzzzzzz away!

The Science Behind the Fizz
Why do the bath salts fizz? Well, it has everything to do with two of the ingredients used in the bath salt mixture: citric acid and baking soda (also known as sodium bicarbonate). Whenever you mix citric acid and baking soda together in water something very special happens. The two things mix together and create new things. Chemists call it a chemical change. In this case, citric acid and baking soda are changed into sodium citrate and carbon dioxide gas. As the carbon dioxide gas is formed, it creates lots and lots of little bubbles...or fizz. This same principle is used to make the well known fizz created by Alka Seltzer when you add it water. You may remember that we use the Alka Seltzer fizz to power miniture rockets (check out the Alka Seltzer rockets activity here).

You might be wondering why we added all the other ingredients (like the corn starch, epsom salt, and sea salt) to the mix. All of these other ingredients help to make you skin feel nice after the bath!

Wondershop Fast Fact: The History of Citric Acid

Citric acid was first isolated from lemon juice by a Swedish chemist, Carl Wilhelm Scheele, in 1784. You find it in all kinds of things. Next time you drink a fruity drink, check the list of ingredients. You will probably find citric acid there. It is also used in candy to make it taste fruity.

Monday, February 2, 2009

Is There Any Science To Groundhog Day


That’s right! It’s February 2nd…Groundhog Day! If you are not familiar with this particular observance, this is how the whole thing works. Early in the morning on Februay 2nd, people gather around the burrow of a Marmota monax; a large rodent also known as the whistle pig, eastern marmot, southern marmot, monk, woodchuck, or groundhog. It is believed that if the groundhog sees his shadow when he climbs out of the burrow, there will be six more weeks of cold, wintery weather. On the other hand, if he doesn’t wee his shadow, the warmth of spring will arrive soon. Here’s an additional little nugget to impress your friends with today: Groundhog Day is a cross-quarter day. That means it fall halfway between the Winter Solstice and Vernal Equinox.

There are a number of cities that host their own Groundhog Day celebrations…complete with their own groundhogs. Here are some of the results from this year:

Jimmy the Groundhog (Sun Prairie, Wisconsin): Six more weeks of winter
Punxsutawney Phil (Punxsutawney, Pennsylvania): Six more weeks of winter
Wiarton Willie (Wiarton, Ontario): Six more weeks of winter
General Beauregard Lee (Lilburn, Georgia): Early Spring
Queen Charlotte (Charlotte, North Carolina): Early Spring
Pee Wee (Mile Square Farm, Vermont): Six more weeks of winter
Dunkirk Dave (Dunkirk, New York): Early Spring

I know what you are asking. Is there any science behind this whole Groundhog Day thing? I did a bit of research and this is what I found out.

Historically, people have observed animal behavior for clues to changes in the weather. For example, geese flying south is a sign of the coming of fall. The reappearance of hibernating or inactive animals is a sign of winter’s end. When German settlers came to Pennsylvania in the 1700s, they selected the groundhog as their seasonal forecaster.

There may also be a meteorological explanation for groundhog day. It is thought that the observance may have roots in a weather phenomenon described in the Scottish poem below:

If Candlemas Day is bright and clear,
There’ll be two winters in the year.

The idea behind this poem can be found in cultures around the world. In the poem, Candlemas Day refers to February 2nd…Groundhog Day. Farmers in ancient Europe noticed that bright, clear winter days are often very cold. We now know that this is caused by high pressure systems. Areas of high pressure pull cold air down from the north. They also sweep away any clouds that might have provided insulation. Consequently, a bright winter day (one on which a groundhog may see a shadow) may be an indication of more cold days to come.

Of course, none of this is sound evidence that groundhog can actually predict the coming of spring. Instead, groundhogs day can be seen as a celebration of the role of scientific observation and prediction in our world. Every day, we make observations about the world around us, attempt to make meaning of those observations, and create predictions about the way things will happen in the future. Groundhog Day is wonderful example of this. Over the course of time, we have combined our observations of animal behavior and weather to create a system for predicting spring. Does it work? Well, that is a question I will leave to you and your children to explore.

Other great sites to check out on Groundhog Day: