What do egg shells, coral reefs, and human bones have in common? They’re all made of calcium carbonate! This brittle mineral compound dissolves in acid. Try submerging an egg in white vinegar (a mild acid) for 24 hours, changing the vinegar, then continuing to soak the egg for about a week. What do you observe?
Read moreSurvival Skills: Science Style
Light travels incredibly fast. In a vacuum, it speeds along at nearly six trillion miles per hour. Ever notice how your feet look distorted when you wade in the water, or how a straw seems to be cut in half where it enters a full glass? When light travels through a medium, it slows down.
Read moreDIY Wave Machine
Waves are everywhere! Electromagnetic waves traverse the vacuum of space. Gravitational waves ripple spacetime itself. Mechanical waves propagate energy through air, water, and other media. Sound is a great example of a mechanical wave. Vibrating molecules disturb their neighbors, which disturb their neighbors, and so on. The individual units don’t move far, but the energy
Read moreSmall but Mighty: Eggshell Architecture
In West Virginia’s New River Gorge, an 88-million-pound bridge spans a chasm eight tenths of a mile wide. Before its construction, drivers detoured for the better part of an hour to navigate the Gorge’s steep, water-carved walls. Today, the crossing takes less than a minute at highway driving speed. (Image credit: Louise McLaughlin.) For most
Read moreDIY Tumblewing Glider
To build a tumblewing glider, start with a long, thin rectangle of paper. We experimented with gliders ranging from about three to eight inches in length and had good results with rectangles roughly 4-6 times as long as they were wide. The lighter and thinner the building material you use, the easier your glider will
Read moreDIY: The Invincible Bag
What do DNA, RNA, styrofoam, and Ziploc bags have in common? They’re all made of polymers! Polymers are macromolecules, or long chains of repeated small parts. They’re stretchy, tough, and omnipresent– polymers even encode your body! Individual molecules are too small to be directly observed by humans, but we can see some of the properties
Read moreDIY: Make a Magnetic Slime Monster!
Did you know that our planet is a giant magnet? It’s true! Without Earth’s magnetic field, compass navigation would be impossible. The field also shields us from cosmic radiation, directing most solar wind far around our planet. In space, large objects are generally too distant from each other to be noticeably pulled or pushed by
Read moreDIY Invisible Ink
The simplest invisible inks consist of organic compounds like lemon juice, vinegar, diluted honey, and even white wine– all substances that subtly weaken paper fiber. Once the liquid dries, it’s undetectable under normal circumstances. Apply heat, however, and the hidden message seems to appear out of nowhere. Organic ink makes the painted area more susceptible
Read moreDIY Electric Motor
Electric generators change mechanical energy into electrical energy. An electric motor does the opposite: it changes electrical energy into physical motion. This conversion is possible because of the Lorentz force. Electricity is just the movement of electrons through a loop, called a circuit. Ever notice how magnets can repel or attract objects without touching them?
Read moreDIY Optics Experiment
Ever tried burning wood or pine needles with a magnifying glass? It works best when you adjust the glass to create a small, bright spot of light. After its 93-million-mile journey to Earth, sunlight isn’t ordinarily hot enough to start a fire, but the magnifying lens focuses a large cross-section of light rays into a
Read moreDIY Batteries
Batteries harness energy from the motion of electrons. How do we get electrons going? Chemistry! Most batteries use a simple oxidation-reduction (or redox) reaction to get electric charges moving. In a redox reaction, one material gives electrons to another. We call the donor the anode and the recipient the cathode. Strategic separation of the anode
Read moreHoliday DIY: Crystal Chemistry
Crystals may seem like a geologic scientific mystery…until you see them grow in your own kitchen! Here is what you will need: Wide mouth jars or cups Pipe Cleaners (You can also use coffee filter paper or experiment with other materials. Even white paper works okay) String Popsicle sticks (Pencils work too!) Borax Note: Borax
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