Science Fair this week

We took a weekend off the previous week as Daphne and I went on our first vacation away from the kids to Asheville NC.  This weekend was the finial prep week for Noelle's (age 9) science fair.  The plan had been to do a light bulb with veggies but we couldn't track down a LED with low enough power requirements (the best we got was 2.5 V and 20mA  which Noelle calculated as needing a grid of 3 potatoes in series for the voltage by 60 in parallel for current @ 0.9V and 0.33 mA per spud in her logs).  I'm just going to post her report from her own words and some of the photos she took.

What Pencil Lead Makes the Best Light Bulb?

Materials:

• Filament (pencil leads 0.5, 0.7, and 0.9 mm)
• Power source (8 C cell batteries - 12 volts total)
• Glass bulb (jar)
• Connecting wires
• Alligator clips (to hold the filament)
• Wooden block (to hold the clips in the jar)

How a light bulb works:

Electricity flows from the power source through the filament in the light bulb to create heat and light. Electrons move through the wires and filament when it's connected to the battery. Some of the moving electrons run in to atoms in the filament causing them to become hot and emit light.

Procedure:

1. Assembled the light bulb with materials including electrical tape to hold things in place.
2. Measured and attached pencil lead (one size and length at a time) to the alligator clips.
3. Place jar over filament to reduce air and burning, as well for protection when it breaks.
4. Attach the power source and start a timer to measure duration.
5. Make observations while it burns about brightness.
6. When it burns out, stop timer and record results.

Results:

Filament size -1/2 inch

0.5mm – 19 seconds, 19 seconds, and 18 seconds

0.7mm – 40 seconds, 41 seconds, and 48 seconds
0.9mm – 100 seconds and 165 seconds (we were concerned about the battery so we only did 2 tests)

Brightness:

The thinner filaments glowed brighter than the thicker ones though for a shorter duration. As the thicker leads burned, they grew thinner and they also became brighter. The thick leads were only bright for the last few moments of their life.

Conclusions:

I think that the 0.5 leads made the best light because they were consistently brighter. They also don't burn out the batteries getting hot enough to be bright. With more time we could try changing the length of the filament as well as try other materials. Sealing the jar with play dough or putty might also affect the light and duration. Being careful of the clips and filament after they burn is important because they get VERY hot!

By Noelle Stam

4^th grade Ms. LeClair

April 13, 2011

Measuring the filament length before each burn

burned out 0.5 mm filament

0.7 mm starting to glow somewhat slower than the 0.5 mm

0.9 mm not glowing at all in the beginning though some some is made

0.9 mm barely glowing initially

0.9 mm glowing brighter

0.9 mm filament finally starts to glow bright as it thins.

Partially burned 0.9mm filament shows thinning.

Stamfam Sister Science Show

Inspiration
This one started with a simple question while driving to the Greensboro Science Museum about how freezing and melting occurs.  I have to admit that I stacked the deck a bit by asking them about gravity affecting light and heavy dropped objects before hand to try and illicit a surprise.  The girls decided to do this one as their experiment of the week and even took the initiative to do it in the form of a news cast in this case, reporting on the event as breaking news for their syndicated Stamfam Sister Show.

Materials
Thermometer - for the freezer, and various water temperature measurements (digital cooking one works great).
2 Cups for water
1/2 Cup Water - heated in the microwave for 1 minute to 88 degrees C

1/2 Cup Water - cooled in the refrigerator  to 11 degrees C
Freezer at -16 degrees C

Notes
The girls decided to check in on the water every hour after recording all of their initial data.  Depending on how you present things you can manipulate the interest and excitement level dramatically.  In this case Noelle and Lana got excited enough to turn it in to a multimedia news event with disagreement between them about the expected results. We recorded temperatures of each glass of water before going in to the freezer and at specified intervals after.  Variations can include different containers, constant starting temps but different solutions, etc.  I did some early peeking and found that ice started forming on the cold water glass at about 45 minutes in this instance while the hot glass was still at 6 degrees C, so setting a more frequent check-in period (I'd say every 10 minutes) would be advisable.  The verdict here was that Lana was right, "cold is cold" as she puts it.

Noelle measuring the hot water at 88 degrees C.

Lana measuring the cold water at 11 degrees C.

In the freezer.

Nucleation

March 19, 2011

Inspiration

This week's science was inspired by a chemistry set about crystals the girls got last year from my parents.  Chemistry sets and supplies are a good source of ideas with some semblance of safety.  Some of these are instant or fast acting process and others are protracted and take place over the course of days and weeks with processes like evaporation taking place.  Today's event is to make some Alum crystals with Alum powder mixed with something unlisted to make it blue.

Materials
100 ml water measured after boiling
Small pot to boil the water (non aluminum)
30 ml of Alum powder with blue
Mixing Bowl (non aluminum)
piece of granite to act as a rough seed bed

Notes
I got to talk about solutions, super saturated solutions, and nucleation with this project.  We talked about the shape of the molecules affecting the shape of the crystals and what role a seed plays in the process.  In this case a rough seed will give multiple nucleation sites so we should see various crystals forming in multiple directions.

Noelle with stylish goggles ready for some chemistry

Measuring and pouring the water for boiling.

Pouring in the Alum while the water boils.

Mixing the 30ml of alum with 100 ml of boiling water makes a very dark blue solution. 

Working together to pour it in to the cup with the seed.

Cover and wait, wait wait.  You'll have to wait for future weeks to see the results.

Here are the results after a week.

Results with different background, I'm still a newbie with photography.

Parallel and Series

March 13, 2011

Inspiration
This is the more prep for Noelle's science fair project, this time focusing on both current and voltage and how they are affected by multiple spuds connected both in series and in parallel which  she'll need to figure out how many spuds to use and in what arrangement to light up an LED.

Materials
4 wires with alligator clips - to connect the spud batteries in various configurations
3 potato pieces - to act as the electrolytic solution
3 galvanized nails - to act as anodes
3 pennies - to act as cathodes
1 pad of steel wool - to buff off any tarnish
1 multi meter - to read both mAmps and Volts (set to 2 mAmp and 20 V settings)

Notes
We measured each spud section's output after buffing the pennies to a nice shine to insure a good transfer.  Each was putting out 0.9 +/- 0.1 Volts and 0.35 +/- 0.05 mAmps which Noelle dutifully recorded.  We took some time to review Anode, Cathode, and Electrolytic Solutions along with what parallel and series meant for connecting them.  We then measured amps and volts in various configurations demonstrating that Volts  of were additive when the spuds are connected in series while current remained constant.  With parallel configurations the volts remained pretty much a constant while current was additive.

We also wrote up Nelle's proposal for the science fair and just need to pick up an LED that will require a step up  in both Current and Voltage from a single spud with no hints from daddy.  I think she has enough knowledge to plan it out properly and make it happen with her spud power data she's collected over the last couple of weeks.

Stamspud Sparker materials

Series Spuds 2.7 V 0.35 mA

Spuds in Parallel with anode (nail) connected to anode and cathode (penny) connected to cathode.

Lana with her 0.9 V  1.1mAmp spud battery.

Vegie Batteries

March 6,  2011 


Inspiration
We are shopping for ideas for a science fair project this week for Noelle and decided to go with the classic fruit/veggie battery experiments.


Materials
Any fruits or vegetables that you want to measure, we included potato, sweet potato, onion, pear, apple, orange, grapefruit, lemon, banana, and tomato.
Bow of water
Anything you want to try dissolving in water, we used salt and sugar for out solutions.
Multimeter or a low voltage light bulb if you want to be more qualitative (for positive results measure with the red lead against the copper Anode and
Galvanized nail to act as a Anode (negative end of the battery)
Copper wire (I used a shot copper pipe joint as all of my wires were braided and not great for stabbing) to act as an Cathode (positive end of the battery)
1 AA battery for comparison.


Notes
We went shopping for various fruits and vegetables to test and took turns stabbing various things in to the test subjects.  I took a little extra time to sharpen the end of the copper tubing with a dremel to make it go in easier and make sure we have a ice non oxidized surface to make use of.  I limited the discussion this time to  just voltage and details about battery chemistry, and will bring up amps again in future iterations of of this concept.  Noelle took careful notes of our results with the Apple earning the top spot, though just about everything was in the 0.7 to 1.0 volt range with a fair amount of variance with multiple measurements of the same subject.  I also made sure to wash off the cathode and anode after each test. 

The materials for electrolytic stew.

The apple posts the highest result at 1.098V

Sweet Potato posts a respectable 0.918V

Bartlet Pear comes in at 0.986V

Noelle diligently taking down the results.

Tomato clocks in at 0.929 V

Lemon tests at 0.996 V

Here are the results measured in Volts

Soaplosion

November 27 2010


Inspiration
This one was inspired by a science video I stumbled across and is super easy to do.


Materials1 Bar of fresh Ivory soap
1 Microwave


Notes
Simply chop up and put pieces of soap on a microwave safe plate and fire it up.  The science discussion is based on the air trapped in the soap while it's whipped during manufacture.  So the same air that makes it the soap that floats also expands in the microwave.  When it comes out after about a minute you get a warm souffle that makes the whole room smell fresh, and is still usable as soap.

Noelle with diced soap

1 Minute later, we get soap suffle.

Egg in a bottle trick

December 4 2010

Inspiration
I did these in 6th grade science class (thanks Mr Green) and once or twice in cub scouts. 

Materials
Milk Bottle
Peeled Hard Boiled Egg
6"x2" strips of paper
Tea light candle
Food coloring
Glass vase

Notes
This is a classic demonstration of combustion and vacuum.  The combination of the combustion and heat from the flame warming and pushing some air out before it goes out, cools and creates a vacuum.  Folding the paper lengthwise helps for getting it in to the bottle fast (as it will be on fire).   As an immediate follow up I got a floating candle to pan of food coloring water to illustrate the same principal with a rising water level.

Test Fitting

Add fire

Add egg

FWOOMP!  The effect is dramatic both on the egg and the girls.

Now to remove the egg from the bottle I just blew in to increase the pressure to let the process reverse itself

Lana getting ready to cover the lit candle to see the same effect in a different light.

We let the candle heat up the air in the vase for a while first before sealing it against the water to get a nice vacuum.

Home made Barometer

December 11 2010

Inspiration
More cub scout science this week with a home made barometer and some lessons about air pressure.

Materials
1 Milk bottle
1 Balloon - sliced open to form the flexible membrane over the bottle
1 Rubber band - to hold the membrane tight to the bottle, we used one of the jumbo punching balloons
1 coffee stir stick - to act as a needle
Elmer's glue - to attache the needle to the middle of the membrane
 a strip of paper to record the needle readings

Notes
This is an easy craftish event to do with the kids but the science and observation will take days and weeks to pay off so be patient.  The construction was easy enough and similar to making a makeshift kids drum with a balloon skin.  Be careful to use a long "needle" and glue it to the middle of the membrane so that the motion at the end of the needle will be clear.  We spent some time talking about air pressure and what would happen if the pressure changed outside the bottle, and the relationship to changing air pressure with certain inclement weather changes.  By looking up current pressure readings from weather.com we were even able to record values for our needle readings over the next few weeks which the kids still got excited about (and would even make their own predictions about the next day's weather based on their readings.

Here's the baseline.

The pressure dropped this day and it started raining soon after.

Water Bending

December 19


Inspiration 
I drew inspiration from this one from Nickelodeon's Avatar the last Airbender and my cub scout experiences.


Materials
Water faucet
Plastic Comb
Wool scarf - to rub some electrons off with


Notes
The physics here involve building up a static charge by rubbing the comb and wool together for a bit and holding it near running water.  Due to the polarized nature of water while in a thin stream you can used the static charge to draw the stream very visibly.  Be careful not to pull it too close because if the water hits the comb it will neutralize your nice charge and negate the effect.  This method also works great for zapping an unsuspecting sister in the ear for an unscientific yelp.

This gave some very clear results.

More great bending action.

Noelle enjoying the power of physics.

Bernoulli's Principal

January 8

Inspiration 
This was another easy week inspired from my cub scouts days (thanks Mom).

Materials
Strip of tissue paper 18" x 2" (newspaper would work just as well)
Vitamin Bottle - any old 3" cylinder would do to create the needed separation


Notes
The setup for this is fast and easy, just cut and drape the strip of paper and make predictions.  I start by blowing right at the side of the strips before asking for predictions of what will happen when we blow between or beside them. They guessed that the paper would move in the same direction that the wind was blowing predictably and were appropriately impressed when the paper moved in a perpendicular direction.  We talked about air pressure and how faster moving air lowers the air pressure and can lead to lift with wings and such. 

Lana making her prediction before blowing between the strips.

Bernoulli in action.

Boyancy and Density

Jacuary 17

Inspiration
This  week was almost completely improvised at the last minute, starting with a memory of an oil & water wave machine jar from cub scouts.  From there I moved to density/buoyancy object tests and predictions.

Materials
Various balls and objects for sink/float tests
1 Glass jar with tight fitting lid
1/2 a jar worth of oil
Water for the wave jar and the sink/float tank
Food coloring to create better contrast in the wave jar

Notes
We started by mixing the food coloring & water and making some predictions about what would happen when we added the water (they went with the oil sinking because it was thicker).  We talked about why they stayed separate for a while though I don't think that sunk in while they were exited about making waves and turbulence.  The discussions about density being the reason that the oil floated went well and we dropped the various objects in the water after making fairly successful predictions for each.  Later this experiment would tie in nicely with the gravity experiments where we reinforced the concept of density.

Forming a hypothesis.

Hypothesis crushed but still fun.

Lana, pretending her head is like the sinking ball.

Noelle showing the contrasting density for two similar feeling bouncy balls.

They made note of how much of each floating ball was sticking out above the waterline.

We started to branch out a bit beyond the balls in the toy bins.