Science/Math

Ooooooooo blech!

Playing with Oobleck (aka Arp) at the Exploratorium

Ooooooo blech: the recognition that something is both astoundingly cool and disgustingly yucky. Now I know why school children call this cornstarch/water mixture Oobleck.

Since I don’t have children in school, the first time I encountered Oobleck was at San Francisco’s mega hands-on science museum, the Exploratorium. An exhibit had this liquid (or is it a solid?) in a giant drum. Press a button, and the drum shook rapidly. The Oobleck turned into a solid until the shaking stopped. I had to try this magic at home.

Fortunately Cooper’s Mind Blowing Science Kit had the recipe: 1/8th cup water and 5 T. cornstarch. Mix it up and enjoy the magic. During stirring, Oobleck becomes solid at the bottom of the bowl and difficult to move. But, if you stop stirring and gently touch the top, it feels like a liquid. The process of hardening under pressure or intense shaking is the opposite of the liquefaction that occurs during earthquakes.

Oobleck is a non-Newtonian fluid, also called a shear-thickening liquid, but it’s not the onlyone. Gravy thickens when you stir it (or so you hope). Struggle in quicksand, and it will be more difficult to escape. These substances defy Newton’s principle that applying pressure twice as hard to a liquid should move the liquid twice as fast. Good luck if you try that with Oobleck. Here’s a great explanation of Newton’s theories.

Mix up these common household ingredients, and check it out. I have to admit, I had even more fun than the kids.

Homeschool, Science/Math, Toys

Chemistry Experiment 2: Color Changing Liquids

Our second mind-blowing science experiment was dubbed “Color Changing Liquids,” an experiment you can easily do at home without special equipment. Our science kit included red cabbage juice powder, which we added to two separate cups of water to create a purplish-colored indicator (a substance that changes color when mixed with an acid or base). To make your own indicator, simply shred some red cabbage and soak it in water overnight. Strain it the next morning, and you are ready to test!

To our first cup, we added citric acid (you could use vinegar), which turned the liquid red. To the second liquid, we added baking soda, which turned the liquid blue, indicating a base. Then, we mixed the two liquids together. The acid and base neutralized each other, creating a purple liquid and released carbon dioxide just like in the “dancing powders” experiment.

Steve Spangler Science has some variations on this experiment. These include ideas for other acids and bases to test and  how to create your own pH  test strips from red cabbage juice. Enjoy!

Homeschool, Science/Math, Toys

Mind Blowing Chemistry Experiments

My sister bought Cooper and Finley the My First Mind Blowing Science Kit for Christmas. The kit has been calling to the boys for a week now: “Mix magic fizzing powders! Create a crystal sunset in a test tube. Make an underwater volcano!” We opened it Saturday and tried our first two chemistry experiments.

Unlike the primary science set we own (which I highly recommend), this one includes chemicals you may not have at home. The first experiment we did was called “Dancing Powders.” Essentially, Cooper combined baking soda (a base) and citric acid powder in water. The acid and base neutralized each other and produced fizzy carbon dioxide gas bubbles as a by-product. As you may recall from school, carbon dioxide is the gas we exhale. Plants breathe in carbon dioxide and exhale the oxygen we inhale.

If you don’t have citric acid on hand (and who does), you can still replicate this experiment at home. This same fizzing process is created when you mix baking soda with any other acid, like vinegar. In fact, baking soda and vinegar are the chemicals commonly used to create exploding volcanoes in elementary school. Just make sure to put a cookie sheet or tray under the container you are using to mix the two, as your concoction might fizz over. And never combine acids and bases in a closed container or they might actually explode.

As a side note: The Queen of Clean recommends pouring vinegar and baking soda down drains to clean them. When you are done experimenting, pour your chemicals down the drain. Two birds, one stone.

You can also replicate this experiment with Alka-Seltzer.  Remember “Plop, plop, fizz, fizz, oh what a relief it is?” That “fizz, fizz” is carbon dioxide escaping as part of the chemical reaction. The Web site Fun Science Project Ideas discusses how you can control factors that might affect how quickly the Alka-Seltzer dissolves in water and stops fizzing. These factors include how much acid you use, how hot or cold the water is and how big or small the Alka-Seltzer tablet is.

Tomorrow, I’ll recount our “color changing liquids” experiment from the same kit and how you can reproduce it at home.

Homeschool, Science/Math, Toys

Short circuiting boredom

Building a circuit

For Christmas, Cooper got a Snap Circuits Jr. kit, which is providing a lot of cause and effect fun. In fact, I’m not sure who is enjoying building the circuits more, Cooper or me. So far, we’ve built a light switch, a fan, a sound-activated speaker (it’s just like The Clapper!) and a station for testing the conductivity of various materials. With the latter we discovered that metal rings, pennies, paperclips and aluminum foil all conduct electricity, while drinking straws, plastic spatulas, cloth and paper don’t. They’re insulators.

Circuits are an area where I am definitely out of my element. A little Web research turned up a fantastic, visual explanation from San Jose’s Tech Museum…..here.  Here’s what I learned: electricity is essentially moving electrons. Remember the atomic particles that orbit an atom’s nucleus like tiny moons circle a planet? That’s an electron. Good conductors have free electrons. When you apply energy, using a battery, for example, these negatively charged electrons move from positive nucleus to positive nucleus. Thus the electricity flows along the wires and into the lightbulb, where it turns the lightbulb on. The Tech Museum site also includes instructions for building your own series and parallel circuits at home without a Snap Circuits Jr. kit, though I think Snap Circuits Jr. is a safer way to play with electrical concepts.

While the circuits kit is labeled ages 8 and up, I  a 5-year-old could easily play with this toy with some assistance. It’s very sturdy and will definitely stand up to some boy handling.

Books, Nature, Outside, Science/Math

Nonfiction Friday: Caves and Caverns

Cooper snatched this book off the shelf during a recent visit to the library’s science section. (We aren’t allowed to leave the library without visiting the science shelves….never ever.) Often the boys grab books that are geared towards older children, and we only end up reading portions of them. Case in point: I currently have a chemistry book called “Tests” at my house. However, “Caves and Caverns” by Gail Gibbons (Harcourt & Brace, 1993) is perfectly appropriate for early elementary students, including five-year-olds.

This book easily captures the imagination of early elementary readers, especially since caves are home to bats and other creepy creatures, like isopods and copepods. Gibbons provides a wonderful explanation of how caves and caverns are formed through erosion. She also discusses key cave features like stalagmites and stalactites, describes animals who live in caves and talks about archeological finds like bone fragments and cave paintings.

Finally, Gibbons supplies an illustrated list of supplies a good caver needs, as well as cave rules and areas with famous caves. After reading the book, I really want to take the boys to Luray Caverns in Virginia, the state I hail from. In the meantime, I think a trip to Santa Barbara to see Chumash Indian paintings may be in our future.

Homeschool, Science/Math

Experiment: Make Your Own Thermometer

This experiment comes from last week’s Nonfiction Friday book: “Temperature: Heating Up and Cooling Down” by Darlene Stille. At the end of the book, you’ll find instructions for making your own thermometer out of simple household items. Since Cooper’s on a weather kick, we decided to give it a try.

(Note: In the spirit of total honesty, I have to say that this experiment didn’t work for us. I’ll offer a few ideas on that later; but, in the meantime, I encourage you to give it a try and see if it works for you.)

What you need:

  • Plastic water bottle (16.9 fl oz) with cap
  • Funnel (optional but makes life easier)
  • Liquid measuring cup
  • Rubbing alcohol
  • Water
  • Food coloring
  • Straw
  • Clay (something sticky to attach the straw to the side of the bottle)

What you do:

Place a funnel in the top of the plastic water bottle. Pour 1/4 cup of water into the water bottle. Pour 1/4 cup rubbing alcohol into the water bottle. Add a few drops of food coloring to the water/alcohol mix. Replace the cap and shake vigorously to mix. Remove the cap and insert the straw. Use the clay to hold the straw into place, ensuring the straw doesn’t touch the bottom of the bottle.

Here’s what’s supposed to happen: When you hold the “thermometer” in your hands, the alcohol/water gets warm and creeps higher in the straw, just like the mercury in an old-fashioned glass thermometer. This didn’t happen for us. I tried warming some water in a glass measuring cup and putting the bottle in it, the same way you’d warm a baby bottle. No luck. My tap water is very hard with lots of minerals dissolved in it. I am wondering if it would work with bottled or distilled water?

When you are done playing with your thermometer, make sure to dispose of the water/alcohol mix by pouring it down the drain or into the toilet. And make sure to dispose of the straw and water bottle where no little ones will get ahold of them.

Somebody let me know if you can get this one to work.

Science/Math, Toys

Great Gift Ideas 2011 – part 1

Growing up, I used to joke that my future children would only  play with wooden blocks. I’ve evolved a little bit since then, but not much. I still favor toys that stimulate imagination, curiosity and creativity. So, with that in mind, here are a few of my current favorites.

1) Anything Lego. Have I mentioned how much I adore this company? It’s pretty easy to find a good, mid-priced set for about $25. Every brick set works with every other brick set; I can tell you my mother-in-law still has my husband’s Legos from 30+ years ago, and they work with today’s sets. Plus, if you lose the directions, Lego has instructions available online for every kit it’s made in the last 10 years. This is a great toy for stimulating creativity and building fine motor skills.

Primary Science Set

2) Learning Resources’ Primary Science Set. I bought this preschool science kit for Christmas last year, and it’s a hit. Everything is made of sturdy plastic. It includes 10 large, water-resistant cards with experiments like making volcanoes or dancing raisins. The kit includes goggles, magnifying glass, eye dropper, test tubes, beaker, funnel, tweezers and more. This kit has helped us learn about science in a hands-on way.

Gears! Gears! Gears!

3) Gears! Gears! Gears! We got our first set of gears last year after playing with them at “Grandmommy’s” house. This year we added the Gears Lights and Action Building Set. The set has glow-in-the-dark and LED pieces, as well as a remote control, so children can make their constructions come to life. I think it’s a great way to learn about cause and effect. We found our set at Costco for about $25, but Amazon sells it online as well.

I’ll have more ideas as Christmas approaches. Happy shopping!