Category Archive: Uncategorized

Aug 31

Last Person to Know Everything

Science Concept Map

Has anyone grasped all human knowledge? Aristotle, two millennia before the printing press? The lesser-known Thomas Young, who published on tides, light, bridges, languages, and Egyptian hieroglyphics? Will our technological progeny ride an exponential growth curve to catch up with all human-computer knowledge? Or does the shoreline of the unknown inevitably expand with the island of knowledge? My …

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Jul 30

Who or what pulls the trigger?

A landmine is autonomous. However indiscriminate its selection of a target, a landmine does not require intervention by a human. Deadly weapons that do not require human intervention date back to pits with spikes, but something new is on the horizon: weapons that are selective in their targets. Concern that artificial intelligence will facilitate a …

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Jun 18

Why do rattlesnake egg magnets rattle?

rattlesnake egg magnet questions

Hold two dark, egg-shaped magnets in your hand, separate them with your thumb, and throw them in the air.  As they arc in the air, they crash together and rattle.  How? Why? We played with them, watched them in the air, watched them on a carpet, listened to them, recorded 120 FPS video, and noted …

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May 12

Ring of magnets cool hand?


Phoenix and Maverick thought they sensed a cooling of their hands when placed within a ring of magnets, so they created an experiment to see if their impressions were accurate and what the pattern might be.  They hypothesized that the magnets could exert a pull on the iron in the blood of the hand, causing …

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May 07

Wind Tunnel and Wiffle Balls

Maverick’s interest in flying saucers led us to studying fundamentals of aerodynamics.  We dropped wiffle balls into a vertical wind tunnel made from a shop vac and sliced 3-liter soda bottles.  The balls behave differently, usually hovering at one of two heights, so we took 3 balls, weighed them, inspected their surface (noticing some had smooth seams …

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May 05

Electrolysis and camp towels

separating hydrogen and oxygen

Max brought a 12V battery and a jar with two tufts of steel wool separated by a sock.  He used baking powder as an electrolyte in the water.  Wiring the jar to the battery worked well, creating enough hydrogen and oxygen to ignite with a match to create the pop you can see and hear …

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Apr 22

Newton’s Cradle completed

diagramming lava lamps

Maverick built a giant cradle with five 15-pound bowling balls.  The saw horse rocked, so we could use stabilization, perhaps with guy wires/strings extending from each end, similar to tent strings attached to ground spikes.  Balls slipped out of line after a few collisions, so we could use a 2nd sawhorse and string balls between …

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Apr 14

Falling through the earth and black hole math

Black hole math

Dave Francis was our guest today.  He apologized for the state of the earth that our generation is leaving for the generation of students.  He then challenged them to devise solutions.  Max, Rhys, and Maverick tackled population, thinking up solutions that Dave and I critiqued and also helped with. Ideas ranged from sending old people …

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Apr 09

Oscilloscope and oscillators

555 oscillator with 3 capacitor placements

    Guest Keith Gudger brought his digital storage oscilloscope to demonstrate. Max brought his State Science Fair-bound project to the be first subject of the oscilloscope.  Max has improved his energy-gathering soccer ball since we last saw it, now using 5 piezoelectric transducers, each with its own bridge rectifier to charge a single capacitor. …

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Jan 31

Vertical wind tunnel and patterns in ping pong balls

Carlin used a shop vacuum exhaust and concatenated translucent 3-liter soft drink bottles to form vertical wind tunnel to illustrate balance between aerodynamics and mass.  Videos show patterns in floating ping pong balls using high speed capture.  First video is with 3 ping pong balls and second with 15.  Balls were striped in different colors …

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Jan 31

Energy harvesting from soccer ball

closing panel

Max is using piezo-electric transducers to convert the energy from kicking a soccer ball into electricity, potentially useful for lighting or cellphone charging. Piezos produce high voltage and low current in one polarity when flexed and then in the reverse when the flex is reversed to return the piezo crystal to a neutral position.  To capture …

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Jan 25

Build an earthquake-safe structure

ready for judges

2015 April 26 Day of the competition! Team 476 Gravity Rex gathered at the Tech Museum of Innovation with our building and engineering journal to compete with thousands of other kids and face a panel of judges. Our engineering journal was pronounced “good” as we could back up everything we claimed about our building and the …

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Jan 13

Winding our own electromagnet


Max brought several electromagnets he made himself as well as wire and cores to make another.  His project to capture energy from soccer balls being kicked will use an electromagnet as part of the kick-testing jig, so he wanted to make a more powerful one. We measured voltage, current, and pull strength for an existing …

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Jan 09

Newtons Cradle spin


Our Newton’s Cradle nears completion.  We are discussing how to secure the cords suspending bowling balls to the saw horse.  In the time we had, we spun the bowling balls.  See the balls behave like gears and also climb up their suspension cords: We inverted a honey jar and observed the speed of air bubbles, large and …

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Dec 09

Hunting polarized lenses in an old TV

Disassembling TV 1

          Inspired by an Exploratorium exhibit called Watching Water Freeze, we placed very thin mica between two polarized lenses to get a similar effect of rainbows.  See the video I took of the Exploratorium exhibit created by Charles Sowers. Since we have just two small polarizer sheets, we disassembled a broken LCD …

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