By Kim Robson:
Little kids are natural scientists. They’re curious about the world around them and are constantly learning new things about how it works. As winter approaches and outdoor time is reduced, here are a few fun DIY at-home science experiments you and your kids can enjoy together!
First of all, these experiments always should be conducted with adult supervision. Also, we always should wear safety goggles. You can find kid-sized ones here.
Bicycle-Powered Light Display
Use scotch tape to securely fix several glow sticks to your kid’s bicycle wheel spokes. Then set them loose after dark and enjoy the light show! Create different patterns of light by rearranging the glow sticks.
Science lesson: Sensory Memory
Why do the three or four glow sticks look like one solid line while the wheels are spinning? This demonstrates “iconic memory,” which is a sensory memory — the shortest-term memory we have — which allows your brain to store an image for the few moments it needs to process what it has seen. The wheels’ motion makes the images appear to all blur together.
Glow-in-the-Dark Fog Bubbles
Add a chunk of dry ice to some bubble solution mixed with the contents of an activated glow stick. The bubbles glow and rise from the dry ice fog. Great for Halloween! Only an adult should handle the dry ice, as it can cause burns when in direct contact with skin.
Science lesson: Sublimation and Chemical Luminescence
Sublimation is a term for the direct change of a solid to a gas without its ever becoming a liquid. For instance, without ever melting first, ice will evaporate in your freezer. Dry ice sublimates into a gas (CO2), and the bubbles trap the smoky-looking gas. Activated glow stick liquid adds excitement, but is also an example of a chemiluminescent, or a light that is the energy byproduct of a chemical reaction.
Salt Crystal Feathers
Boil a pot of water and stir in table salt until a layer of crystalized salt forms on the top — it’ll look a bit like ice. Pour salt water into mason jars. Clip a feather into a clothespin or binder clip, then suspend the feather in the solution. Set your jars in a sunny window. Salt crystals will start developing in a couple of hours. Leave the feathers in the solution for two or three days, then pull them out and let dry overnight. Be sure to look at them under a magnifying glass!
Science lesson: Super-saturation, Evaporation, and Chemical Bonding
Salt crystals form due to the high concentration of salt in the water. When the water evaporates, the salt has to go somewhere. When the feather is placed in the water, the salt molecules (NA and CL) bond together around the feather. Over time, the salt crystals grow. Salt crystals always form a square or rectangular shape.
See how plants “drink” water with some added food coloring. Bring home some white flowers (carnations and gerbera daisies are good) or use stalks of celery, and submerge them in colored water. You can even split the stem of one flower and place each end in separate colors of water. Watch the colored water slowly seep through the plant’s “veins” and into the flower petals. You should have a colorful bouquet after just the first day.
Science lesson: Capillary Action
Xylem is the name for one type of plant tissue that carries water. It comes from the Greek word xylon, meaning “wood.” The other tissue is called phloem. It comes from the Greek word phloios, meaning “bark.” Together, these tissues form the main capillary action that helps plants absorb water and nutrients to survive.
The word “oobleck” comes from a Dr. Seuss story in which a young boy must rescue his kingdom from a sticky substance. Oobleck is a mixture of about two parts cornstarch to one part water. It is a non-Newtonian fluid: when struck, it acts like a solid, but when allowed to relax, it acts like a liquid. Oobleck is used often in demonstrations to exhibit its unusual properties. A person can walk across a large vat of oobleck without sinking as long as the person moves quickly enough and steps with enough force to cause the thickening — but will sink in if he or she stops for a moment.
Mix up enough oobleck to cover the bottom of a thin cookie sheet. Place the cookie sheet on a speaker or subwoofer, and pour in the oobleck. Download different test tones to play – 40 Hz, 50 Hz, and 63 Hz seem to work the best. You may need to turn the volume up, and you may need to apply gentle pressure to the cookie sheet. Add some food coloring for fun. If your oobleck isn’t dancing, try changing the volume on your speaker. You also can try digging your finger into the oobleck to start the movement. In the video below, the kids do that a few times just to get everything started.
Science lesson: Sound Waves and Non-Newtonian Fluids
When agitated by the sound waves, the oobleck thickens and forms standing waves in response to low frequency sound waves from the subwoofer.
For more experiments, check out The Curious Kid’s Science Book: 100+ Creative Hands-On Activities for Ages 4-8.