How Does That Work: Frustration Bottles

There are so many things you can talk about with this demonstration: solubility, density, immiscibility, etc.  It also makes a good How Does That Work demonstration. 

In short:

You have three bottles, each made of two layers, but in one bottle the layers are reversed.  The bottles are filled with water (on the bottom) and baby oil (on the top).  In two of the bottles, the water is colored with water soluble food dye (which will color water but not oil).  In the third bottle, the oil is colored with liquid candle dye (which will color oil, but not water).

In long:

You'll need:

3 (500mL) water bottles

750 mL baby oil

750 mL water

food coloring

liquid candle dye

Fill 2 of the bottles with 250 mL of water.  Fill the remaining bottle with 250 mL of baby oil.

Use the candle dye to color the baby oil (do this before coloring the water - the water and food coloring are much more forgiving and easier to dispose of should you need to start over).

Use the food coloring to color the water, attempting to match the oil color as best you can.  Keep track of what you used and repeat with the second water bottle.

Into the bottle with the oil, add 250 mL of water.

Into the two bottles with water, add 250 mL of baby oil to each.  Cap.  (You may wish to run some glue along the cap so they are more resistant to being opened).

Leave the bottles on your front table/desk and let the students explore.  They'll try to turn the "wrong" one upside down.  They may try to shake them and then watch them separate.

Should lead to some good discussions!

You can keep these forever - put them in a safe spot until you need them the next time!

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How Does That Work is a series of products and demonstrations that you can present to your students and challenge them to explain the science of how they work. Make sure you decide ahead of time what you'll accept as a valid explanation - can it be printed straight off the internet, written in the student's own words, or does the student need to be able to explain it to you conversationally? What will a valid explanation earn the student - a prize, extra credit, a feeling of goodness?

Rate of Solution: Sugar Cubes

I did this with 4th grade students who were learning about solutions. It's simple, but they have a good time and learn a little something in the process!

For each pair of students, you'll need:
-Cup/Beaker
-4 Sugar Cubes
-Spoon
-Stopwatch

For the whole class:
-Hot Water
-Room Temperature Water
-A means of crushing sugar cubes

Provide each pair of students with a cup (clear is better - it's hard to see a white sugar cube in a white cup) of room temperature water.

Have them drop a whole sugar cube into the water and time how long it takes for the cube to dissolve (no stirring).

This is their baseline measurement. They'll now test several variables, one at a time.

With a fresh cup of room temperature water, drop in a whole sugar cube and time how long it takes for it to dissolve when you STIR it.

With another fresh cup of room temperature water, drop in a CRUSHED sugar cube and time how long it takes to dissolve (no stirring).

Get a cup of HOT WATER, drop in a whole sugar cube and time how long it takes to dissolve (no stirring).


There are several ways to conclude this experiment. Try one or more...
1 - Have students create bar graphs of the data:
-Room Temperature water vs. hot water
-Stirring vs. not
-Crushed cube vs. whole cube

2 - After students have analyzed their data, have them race to see who can dissolve their sugar cube the fastest. They've got three choices to make: hot or room temperature water, will they stir or not, and will they use a crushed cube or a whole cube.

3 - Along the same lines as #2, have a contest where students try to prevent a sugar cube from dissolving for as long as possible.

Solubility: Tie Dye Nametags

Here's an art project, that's totally based on science!

Background information:
Substances are classified as polar and non-polar (if you're interested in learning more about what exactly this means, I'll let you Google it). Polar substances can dissolve other polar substances (water is polar, sugar is polar, therefore sugar can dissolve in water), but they cannot dissolve non-polar substances (water is polar, oil is non-polar, therefore water cannot dissolve oil). This is summarized as "like dissolves like".


For this activity you'll need:
**Cardstock
**Shaving Cream
**Pie pans
**Food Coloring
**Toothpicks
**Straight edge tool (for scraping) - a ruler works
**Paper Towels

The procedure:
1. Spray a layer of shaving cream into the pie pan.
2. Add a few drops of food coloring to the top of the shaving cream (you can use multiple colors).
3. Use a toothpick to mix the color into the shaving cream.
4. Place the piece of cardstock on top of the shaving cream.
5. Peel off the cardstock and place face up on paper towel.
6. Using the straight edge, scrape off the shaving cream from the cardstock.
7. Allow cardstock to dry (won't take very long).

You can dye multiple pieces of cardstock with the same shaving cream before it needs to be replaced.

Why it works:
Paper and food coloring are polar substance so the paper absorbs the food coloring. Shaving cream is mostly non-polar, therefore the paper will not absorb it.