Stargazing onthe White House Lawn

From The White House Blog

The White House South Lawn was lined with telescopes and science exhibits featuring moon rocks, mars rocks, meteorites and more for Astronomy Night earlier this month. The President and First Lady invited local middle school students to star-gaze and welcomed space heroes Buzz Aldrin and Sally Ride, as well as two remarkable science students, Caroline Moore and Lucas Bolyard to come share some of their wisdom. Caroline was just 14 years old when she became the youngest person ever to discover a supernova and Lucas, a high school sophomore, discovered an extremely rare kind of star called a pulsar.

Read more here. You can also watch the live chat with Sally Ride, the first American woman in space, here and the President's full remarks here.

Bubble Science: Make Your Own Bubble Solution

Who doesn’t like a good bubble? Who knew that a bit of air trapped in film of soapy water could be so much fun? Most people have fond memories of summers filled with bubbles. However, most people don’t know that science behind the spherical shape and swirling colors that make up bubbles. Keep reading and discover how to make your own super bubble solution.

Here’s What You Need

• 2 tablespoons of dish soap
• 1 tablespoon of Glycerin
  
• Bubble wand
• 1 cup of distilled water
• Cup or bowl

About the Ingredients...

Water – All good bubble solutions contains water. However, it is important that you use good quality water (e.g. distilled water).

Dish Soap – You don’t need great soap to make your bubbles. In fact, you want to avoid anti-bacterial soap or soap with a lot of additives. Old fashioned Dawn works very well.

Glycerin – You can buy glycerin at your local drug store. You may have to ask the pharmacist for it. It may be a bit expensive, but glycerin is very important to the bubble solution. It gives your bubbles extra strength! NOTE: If you cannot find glycerin, you can substitute Karo syrup.

Here’s What You Do
Mix the dish soap, glycerin and water in the cup or bowl. Dip your bubble wand in the solution and blow a bubble!

Here are some things to try with your bubble solution:

• Can you catch a bubble?
• Can you blow a really big bubble?
• Can you touch a bubble with your finger?
• Can you bounce a bubble off your hand or your clothes?

The Science Behind The Bubbles
You probably didn’t realize it, but water is pretty sticky. It sticks to other things (e.g. the window, the side of a cup, and you) and it sticks to itself. When molecules of water stick to other things, it is called adhesion. When molecules of water stick to each other, it is called cohesion. If you look at a drop of water very closely, you might notice that it is round. The cohesion of the water molecules creates surface tension and gives the drop its round shape.

The surface tension of water is very strong. Some bugs can actually walk on water because water’s surface tension is so strong. Unfortunately, it is too strong for bubbles. That’s why you add detergent to the bubble solution. It actually reduces the surface tension of water. It also slows down the evaporation process, so your bubbles last longer.

When you dip your bubble wand in the bubble solution, the soapy water sticks to the wand. The water molecules also stick together forming the thin, colorful film of bubble solution. When you blow into the film, a bubble forms. The bubble encloses the most amount of air with the least amount of bubble solution. As a result, bubbles are always round!

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.

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.