This week's campers.

And most of the helpers, many of whom were campers in years past.


Making star projectors was the first project in astronomy.
The kids had to carefully cut out the segments and cap of what will be their own mini star chart projector.

A few of the constellations they learned about.

Then they had to assemble the pieces into a dome.

They made a model of the constellation of orion with the stars (represented by beads) at the appropriate distance from the observer.
Even though they look like they are on the celestial sphere they are quite far apart.
Distances range from 243 to 1350 light years away from us.

Building foam rockets with rubber band "engines".
These will be used in a contest on Thursday.

Design, fabricate and attach the stabilizing fins.

Check them out then have some fun test firing them.

Looks like one is about to hit the target and a second one might.


Here they started with a game/problem of how to allocate resources.
The Popsicle sticks represent just one resource, trees.
It is up to your team to decide what is most important to you.

A chart of some of the things the class discussed.

They used sun print paper to investigate the UV protection factor of sunscreen.
They also made shadow prints of seeds and leaves that they collected.

Have you ever collected some of your cells and extracted the DNA.
Follow directions carefully and it isn't hard.


Or rather returning from it.
The food was excellent contrary to what you may think by looking at the guy in the middle.


Ancient Greeks knew that there was something strange about amber.
When they rubbed it on fur it would attract bits of dust and paper.
Their word for amber was electro from which we get our words electron, electricity, electromagnetic and others.
These kids are examining some amber.

Ben Franklin would have recognized these electroscopes and understood how they worked.

We all made our own using aluminized mylar a paper clip and an empty water bottle.

And they worked.
When a balloon is rubbed on some fur, or hair, it becomes negatively charged.
When it is brought near to the top of the electroscope electrons are repelled down the wire and the two pieces of mylar become negatively charged.
Since they have the same charge they are repelled from each other and move apart, much to the delight of the kids.

A Van de Graaff is a device that can generate very high voltages.
This one has produced more than 300,000 volts.
When we put a stack of aluminum pie plates on the top of it and turn it on the plates become charged and fly into the air.
It is a challenge to catch them.



If you are insulated from the ground and touch the top of the Van de Graaff you become a sort of electroscope yourself.
Note the hair.

The same thing happens with a pompom fastened to it.

There is more than enough voltage to light this string of xenon flash tubes.

Or electrify these girls.
They all seemed to want to find out what it felt like.
We kept the lights dim and brightened the pictures later so we could see the sparks better.



We made a chain with kids holding on to florescent light bulbs.
When the person next to the Van de Graaff let a spark jump the lights would flash and the kids would jump.



You can get a big spark through the air between the bowl and the Van de Graaff.
Or you can use a string of conductive beads with insulating string between them.
The second technique gives you more time to anticipate the result and may give a stronger shock.

On Tuesday we built accelerometers to measure both horizontal and vertical acceleration.
They could be used on a roller coaster going around a bend or over the top of a hill and plunging down the other side or bouncing on a trampoline.

We took a spin and studied the conservation of angular momentum.
I would get the kids spinning while they held the jugs with their arms outstretched.
When they pulled their arms in they would turn much faster, just like an ice skater.

On Wednesday we investigated sound.
They got to try some of the musical instruments: bugle, ocarina, singing bowl, kalimba and others.
The boys in the second picture are making music with nose flutes.

This long spring illustrates the motion of a sound wave through the air.
Each turn is like a molecule and when I compress a few turns and then release them it is like I just made a pulse of sound by clapping my hands once.
The compression wave moves along the spring and when it hits the end it is reflected back like an echo.

The singing rod is just a piece of aluminum that has a slightly sticky coating.
As I slide my hand along my finger and the rod are both slightly stretched then they slip.
This makes a pulse travel along the rod.
When it hits the end it bounces back.
When it gets to my hand it shakes it a bit causing it to slip again and another pulse starts.
This continues with the vibration getting stronger with each pass.
The same thing happens with a wine glass or singing bowl.

We used a sound level meter to measure the volume when the class did several things.
Because sound at high volume can damage your hearing we covered our ears when they all yelled.

Compare these levels to the regulations that businesses have to comply with to protect their employees.

We also tested their earphones and ear buds to see how loud they were.

The kids suggested some unique names for our model with the electronic ear.

Over the two weeks of camp we tested 97 sets.
We had the kids set them at their normal listening level and then at the maximum that their player could produce.
The highest normal listening level was 115 dBa and 25 of them were above 90 dBa.
When the players were set to maximum the highest level was more than 115 dBa for 45 sets and it was more than 100 dBa for 63 sets.
Only 18 were less than 90 dBa.
After looking at how the ear works the kids understood that they could damage the hair cells in the cochlea which would result in tinnitus and hearing loss.
I hope they keep the volume down so that doesn't happen.

They put strips with a special pattern of bumps on them through the bottom of plastic cups.
When they slid their thumb nail along the strip the cup said " Science is fun."

The kids built kalimbas, an African musical instrument.
They used Popsicle sticks held by a strip of wood, some foam tape, a piece of bamboo skewer, and two large binder clips clamping everything together.
Then you slide the Popsicle sticks in or out to tune them so you can play music.

Straw oboes, whizzers, and a video of the Tacoma Narrows bridge collapse finished out the day.


The binary system is used to represent numbers inside computers.
One and zero are all that is required.
The binary system uses place values like the decimal system except each column increases by a factor of 2 rather than 10.
So pieces of wood with lengths of 1, 2, 4, 8, and 16 can be used to make any length from 1 to 31.

The same idea lets these kids can display any number of dots from 1 to 31 by showing some of all of these 5 cards.

Here the dot cards have been replaced by 0s and 1s still representing the columns of a binary number.
The number they are showing is 0x16+1x8+0x4+1x2+0x1 which is equal to 10 in the decimal system.

Each column of this clock display is a different binary number.
Taken together they represent 03:34:06. 
Do you see how?

A binary checksum was the basis of a "magic memory" trick done with the post-its on the board.

These kids are working on the design of a roller coaster.
When they were done the computer would tell them about potential problems like too high a g load or too sharp a turn.


Safety first, they dyed their own pair of safety glasses that they will use in classes during the week.

These bits of felt will be used to make moles which will serve as a reminder of the mole that chemists use to calculate the quantity of chemicals that are required for a reaction.
 
Mole construction.

And some completed moles.

Slime made from polyvinyl alcohol and borax solutions.
You can imagine polyvinyl alcohol (PVA) molecules as resembling limp strands of spaghetti that are as long as a football field.
When dissolved in water they easily slide over each other.
The sodium borate molecules are much smaller, imagine pinhead size.
Each solution is nearly as runny as water.
However, when they are mixed the borate ion forms links with random spots on the PVA molecules and the mix becomes very gooey.
The mix is still almost all water (96%) so it is surprising that it's consistency has changed so much. 

Generate some hydrogen by reacting aluminum with an acid.
Note that the reaction produces heat as well as enough gas to inflate a balloon.

Secure it so that it can be ignited safely.


   

Here the kids are showing off some of the projects they made.


Every year campers participate in a variety of challenges.
The Straw Tower is one that they make at home and bring in to have tested.
They put a container on top of the tower and then marbles are put in the container.
There score is based on the product of the height and the number of marbles it held before it collapsed.

Here is part of one of the tests.


Other contests were rocket golf, aluminum foil boat, periodic table words, water balloon bomber, paper tower, hidden shapes, left turn airplane, blindfold maze and Who Wants to Win $1,000,000 (not real money).




When the campers had a little free time between the contests there were puzzles and games to try.


Team and individual winners for the contests.


This year's field trip was to an amusement park where we checked what we had learned in camp with real world observations.
We also had a lot of fun.
 






We all had a great time at camp.
Hope to see you again next year.