Make Simple Bomb

Risky, fun science for kids

As parents try to shelter children from risk, and as TV, video games and the Internet dominate kids' lives, Tulley's book is a breath of fresh air. If we can get our children to engage in risk, experimentation and critical thinking, Tulley argues, we can improve our educational system and build a generation interested in, even passionate about, science and technology. "Taste" sensations occur when chemical receptors activate nerves in the tongue, which then send the "taste" message to our brains. Normally, these chemical receptors are grouped together in regions of our tongue meant for certain tastes. However, the battery terminal generates a current that activates a variety of nerves (spanning a wide range of chemical receptor regions) in the tongue. Thus, Tulley writes, the "taste of electricity" will be an "exaggerated, nonspecific taste." Chewing aluminum foil achieves a similar effect because a current is generated when aluminum contacts the acidic saliva in our mouths.

Place 2 tablespoons of baking soda on a small piece of paper towel, then fold the paper towel in half to create a semi-sealed packet of "reactant." Next, make an "acid pool" by mixing 1/2 cup of vinegar and 1/4 cup of hot water in a plastic bag. Insert the paper-towel packet of baking soda into the bag with the acid pool, without letting the packet touch the water-vinegar mixture. Tulley says this can be done by carefully holding the pack above the acid pool in the bag while sealing the top of the bag shut. Last, toss the bag away so that the baking soda, water and vinegar mix, and the bomb goes off.

The first item to zap (for no more than 3 seconds) is an unwanted CD. When this thin sheet of metal absorbs microwaves, interesting results follow.

To make a "grape antenna," cut a grape in half (leaving the two halves connected by the "hinge" of skin), and microwave it on full power for 10 seconds.

Finally, heat a marshmallow for 10 seconds on full power.

The grape experiment shows how the size of grapes, relative to the wavelength of the energy produced in a microwave, makes for "highly efficient" antennas.

Marshmallows have a very high water content, which enables them to absorb microwaves. They also contain pockets of trapped air that allow them to heat up very quickly. And their stretchy nature lets them expand to great sizes.

Find a narrow, swift-flowing channel for the site of the dam, and avoid damaging any surrounding natural features. A creek or stream can easily be dammed with "leaves, sticks, mud, rocks, sand, and gravel" found nearby. To protect against building water pressure, Tulley says, pack rocks at the bottom of the dry side of the dam and temporarily reroute the water that may pool upstream. Once the experiment is complete, deconstruct the dam to "restore the creek to its original condition.

A fun and simple homemade smoke bomb recipe « steve cross loves ...

Part of my intense nerdyness comes from my childhood when I was obsessed with fire. Yes, like many young boys, I was a pyromaniac. And I still am. I’m just a much safer, more cautious pyromaniac. Every year for the 4th of July I like to indulge my inner 14-year-old boy by buying and even making my own pyrotechnic devices. I thought I would share one recipe/method for making a homemade smoke bomb. It’s pretty simple and safe- provided you follow these directions very carefully.

Ingredients: Equal parts sucrose (aka table sugar) and potassium nitrate (aka saltpeter or KNO3), a container, and a fuse. (Just pull a fuse out of a bottle rocket.)

Saltpeter is relatively easy to come by if you know where to look- it can usually be found in small mom & pop drug stores (never chains like Walgreens for whatever reason…) or in hardware stores where it’s sold as stump remover. There are several different kinds of stump remover but the one you need is usually called “stumpout.” Just check the label and shake it to make sure it’s really potassium nitrate in powder form. I used stump remover in the one I made last year and it worked great.

Mix the KNO3 and sugar (equal parts) together well and put them into a saucepan or pot. Heat the mixture in the pot VERY SLOWLY on an ELECTRIC stove eye. Let me say that again- heat it VERY VERY SLOWLY on an ELECTRIC stove eye. DO NOT heat it on a natural gas stove as it will greatly increase the risk of accidental ignition. The electric stove eye provides a slower, more gradual source of heat. Obviously, the best place to do this is OUTSIDE on a portable heat plate, and be sure you wear some kind of eye protection. Carefully monitor and stir the mixture and as soon as you notice it starting to melt, turn the heat back down just a bit- you want the bare minimum amount of heat necessary to melt the mixture. It will begin to turn a brownish orange color- keep stirring and monitoring the temp. Once it’s all a gooey liquid, pour it into whatever container you’ve chosen and insert the fuse. Simply allow it to cool and harden and you’re good to. Don’t try to make a really huge one, either- if the chunk is too big it will burn too fast and potentially explode.