Kids Chemistry Solutions

In chemistry, a solution is when something (a solute) is so thoroughly dissolved in something else (a solvent) that they become one homogeneous mixture.  In real life, we do this all the time!

First up we sprinkled crystals of Kool-Aid (from the packet, not the sugared variety) into water and watched them dissolve.  You can see the crystals fall through the water trailing streamers of dissolved red.

Then we looked at the effect of heat and stirring on the rate of dissolution (dissolving). 

I set up four jars, two with ice water, and two with boiling water.

Then I dropped a bouillon cube into each jar.  The first jars had hot or cold water; the second set also had one hot, one cold, but we added spoons to stir with.

The hot stirred cube dissolved first, followed by the hot jar with no stirring.  Neither cold jar showed much dissolution.

 Next up we looked at how quickly gummy worm segments dissolved in our mouths.  This was a favorite experiment!

Each kid got three small segments.  For the first, they had to hold it in their mouths without moving it around for one minute.

For the second, they moved it around their mouths for one minute.  For the third, they chewed it for one minute.  Making your solute smaller and moving it around definitely speeds dissolution!

 Next we discussed saturated solutions.  For most solutes and solvents, there comes a point at which no more solute can be absorbed by the solvent.  We did this with sugar and water, adding sugar until no more could be stirred in.

Then we put the pot on the stove and made a super saturated solution.  We got the solvent to hold more solute by adding heat!

Sure enough, the leftover sugar went into solution as soon as the water was hot.  We set it aside to cool and eventually added it to the Kool-Aid solution to make, well, Kool-Aid!

Of course, some solutes will not combine with some solvents.  We call them immiscible, and the obvious example is oil and water.  I had each kid make a bottle with oil and colored water (and glitter, feathers, beads and whatever else looked fun).  

Lastly, when is a solution not a solution?  When it is a suspension or a colloid. 

In a suspension, the solute is not at all absorbed by the solvent, and the particles will eventually settle out. An example of this would be a flour water mixture.

In a colloid, the particles will not settle out, but they remain somewhat distinct from the solvent.  Milk and jello are both colloids. 

You may be wondering in what way the particles in jello and milk are somewhat distinct!  There is a fascinating and easy test known as the Tyndale effect.  Just shine a beam of light through your solution (probably in a dark room).  If you can see the beam in the "solution,"  it's not a true solution, it's a colloid or suspension!

We tested sugar water (solution), mint jelly (colloid), flour and water (suspension), tea (colloid!),
diluted milk (colloid), and Kool-Aid (colloid).  We used a laser pointer, but, before I found the laser, I used a flashlight covered in foil with a pin hole to let out a single beam of light.

If you're curious, whether something forms a solution, colloid, or suspension is dependent on particle size.  Only tiny particles form true solutions, and very large particles will settle.  Colloid particles re in between those sizes.

HT to Klenda for taking the pictures!

A Proud Moment for Me

Zorg (talking to Mxyl in Japan via Skype): Would you rather be attacked by an orange grasshopper the size of a moose, or a pink and yellow polka dotted moose of normal size?

Mxyl: Oh, definitely the grasshopper.  With the current oxygen levels in our atmosphere, the spiracles of the grasshopper couldn't transport enough oxygen for it to function.

Skyping With Sock Puppets

We hadn't really used Skype before Mxyl and Klenda went off, but now we're using it twice a day to keep in touch.

Klenda is back now, but it was she who came up with the idea of Skyping with sock puppets.

Except she didn't have a spare sock!

Other fun things with Skype:

"Showing people around" a distant location (very nice since I'm unlikely to visit Japan anytime soon).

Using bizarre camera angles.

Flipping the webcam and screaming that the world has turned upside down.

Pretending you are passing an object through the computer.

And, don't forget, humming the Jaws theme while bringing your open mouth ever closer to the camera.

Plus you can talk to people.  Very good for knock knock jokes.

Poem of the Week

Another favorite!

OPPORTUNITY

by: Edward Rowland Sill (1841-1887)

HIS I beheld, or dreamed it in a dream:--

There spread a cloud of dust along a plain;

And underneath the cloud, or in it, raged

A furious battle, and men yelled, and swords

Shocked upon swords and shields. A prince's banner

Wavered, then staggered backward, hemmed by foes.

A craven hung along the battle's edge,

And thought, "Had I a sword of keener steel--

That blue blade that the king's son bears, -- but this

Blunt thing--!" he snapped and flung it from his hand,

And lowering crept away and left the field.

Then came the king's son, wounded, sore bestead,

And weaponless, and saw the broken sword,

Hilt-buried in the dry and trodden sand,

And ran and snatched it, and with battle shout

Lifted afresh he hewed his enemy down,

And saved a great cause that heroic day.

HT: Poetry Archive

Spring

Two weeks ago we had this.

And this week we had 90 degrees and this.

Crazy!

But very pretty.





And I'm enjoying the flowers while I can, since they will not last long in this heat.

On the other hand, I'm really, really enjoying the flowers!

These double white daffodils and hyacinths are in Zorg's garden.

 These tulips are in Klenda's garden, in front of a Mary statue.

 I love tulips!

And daffodils, I love all kinds of daffodils!

These were picked from all the kids' gardens in honor of the Feast of the Annunciation.



 I love these ones that Leena picked from her garden.  I like the shape of the perianth (the petals in the back) and ring on the trumpet (corona).  The cheery yellow with the bright orange eye really pops!

Best of all, my favorite daffodils have just started blooming: a pink trumpeted beauty called Fruit Cup.

The C &O Canal in Spring

 This ended  up being a very different trip than the time we came here in the Fall.

For one thing, we went into the Tavern (now a museum) and looked around and played checkers.


Then we went for a walk along the canal, looking at the system of waterfall, locks, and spillways that maintain the water levels along this artificial river.

Finally, it was time for a ride on the canal boat!


I'd never been through a lock before, and it was amazing!

We were pulled into the lock by a person. 

It was interesting to see how much floating weight a single person could pull.  The guide told us the smallest child (probably three years old) could pull the whole boat with us on it. Physics!

Once in the lock, the lock master opened the lock with a key.  The key is the large wrench he is pulling on.  It opens panels within the door of the lock, and water gushed through.

Immediately we felt the boat rise in the lock! 

It turns out that "lock" comes from the fact that we are "locked in" by the water pressure against the doors until the water level equalized.

Once through the lock, they hitched up a team of mules, and away we went!

They talked a lot about the reason they used mules.  I knew they were stronger and tougher than horses.  I did not know that they are smarter than horses.  A well trained horse will follow orders, even when the animal thinks it's a dangerous command.  A mule, evidently, will tell you when they think you are wrong about something.

They also talked about the kind of boats on the canal, pertiularly about passenger "packets" like ours.  In the 1820s, the passengers often amused themselves with music, so we ended our ride on a high note with a concertina and an array of home style instruments.

By the end of the ride, it was in the mid 80s, and the lovely breezes on the boat were dying down.  It was just starting to be sticky and hot (heading up to 90), so we opted out of the walk down to see the falls. 

They played on a large pile of sand, and in a hollow tree for a few minutes, and then we headed home.  We'll go back and try the falls when it's cooler!

The Beautiful Table

I wish I had taken a "before" picture!  It was covered with a flaking black finish, and really looked like nothing special.

But now...

Great job, Pa and Klenda!

The lamp was from the same shop.  It wasn't working, but Pa rewired it for her.  He taught me to rewire lamps at about the same age!

Kids' Chemistry: Phase Changes

I think the 2 most essential things for kids to understand about phase changes is that atoms and molecules are attracted to ("stick to") each other, and that phase changes require energy.

The reason that everything isn't solid is that energy (which we perceive as heat) makes the atoms and molecules move, and the faster they are moving the harder it is for them to "stick" to each other.

To illustrate this, I had the kids play Crack the Whip.  If you haven't played in a while, the kids hold hands in a line and one kid on the end starts walking, then running, making curves.  When they are moving slowly, it's pretty easy for all the kids to stick together.  As they speed up, it gets harder and harder, and eventually, the kids on the end go flying off.

That's a lot like what happens when water boils!

We talked about the phase changes:
Freezing (liquid to solid)
Melting/thawing (solid to liquid)
Evaporation/boiling (liquid to gas)
Condensation (gas to liquid)
Sublimation (solid to gas - think dry ice)
Deposition (gas to solid - this is how artificial diamonds are made)

Then I had them all be molecules and, as I called out phase changes, they altered their motion to suit the change.  Very fun!

We next worked on altering phase changes.  I had put a pot of water on to boil, and we measured it's temperature: 212 degrees.  The idea that water doesn't get any hotter than that, even if you add more heat, was a bit of a new concept for them, so I stayed with that for a while.

I also explained the Fahrenheit and Celsius systems.  Then I dumped 2 cups of salt into the boiling water and got the temperature up to a whopping 227 degrees!

Never one to be wasteful, I then put the potatoes in to cook for dinner.

Next we altered things in the other direction.  I had two jars with ice and a little water.  I put rock salt into one, and then had the kids feel the difference in temperature between the jars. Given enough time, and a cooler room, the salt water jar would have gotten frosty.

Breaking the bond between sodium and chlorine in the salt takes energy, and the salt gets that energy from heat in the ice.  This doesn't make it warmer, it makes it colder because more energy has been absorbed.(converted from heat into chemical energy).

I used to wonder why the ice would melt if the salt was making it colder.  The answer is that the charged sodium and chlorine ions pull the polar (charged) water molecules away from the ice crystals, back into a liquid state.  Interestingly, 0 degrees Fahrenheit is the temperature at which a saturated salt solution freezes.  I still like Celsius better.

Anyway, to get back to the greater significance of salt lowering the temperature of ice, this is how we make ice cream by chilling the container below the freezing point of cream by harnessing the power of ice and salt! Mmmmm.  Ice creammmm.

Anyway, we also picked up ice cubes with thread.  We had mixed success with this because the room was very warm, but the idea is to lay the thread on the ice cube, then sprinkle salt over it.  The salt melts the ice, but chills it enough to refreeze around the thread.  You need cotton thread for this.

Lastly, we looked at evaporative cooling.  This is a good way to concretely experience the need for energy in order to make a phase change.

I had a bottle of alcohol and a bottle of water at room temperature.  I put some of each on cotton balls, then rubbed them both on kids' arms.

I happened to have a scanning thermometer that records surface temperatures (thanks Mumpy!), but you can feel the difference in any case.  The water feels one temperature as it goes on your arm, then the whole area feels cooler as the water evaporates.  In order to make the jump from liquid to gas, the water has "stolen" heat energy from your arm.  You feel the loss of heat as "coolness." That's why sweating works!  The alcohol does the same thing, but, since it evaporates faster, it removes energy more quickly and feels cooler.

Oob Says

For you.  Because it's Monday morning after a week long vacation.



(When asked if he giggles when I push his belly button) Of course!  That's why God made giggle buttons!

When I trip, after the tripping sound stops, I can hear my blood cells wiggling around. (Really?!)

Poem of the Week

One of my all time favorites!

Ozymandias
Percy Bysshe Shelley

I met a traveller from an antique land
Who said: "Two vast and trunkless legs of stone
Stand in the desert. Near them on the sand,
Half sunk, a shattered visage lies, whose frown
And wrinkled lip and sneer of cold command
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them and the heart that fed.
And on the pedestal these words appear:
`My name is Ozymandias, King of Kings:
Look on my works, ye mighty, and despair!'
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare,
The lone and level sands stretch far away".

HT: Online Literature