This is one of my favorite projects, as it really teaches the kids how to make switches that power a motor both forward and reverse as well as chassis design and waterproofing thrusters.  Kids that make this R.O.V. project are often surprised by how much of a role buoyancy plays out in their robot, but with a few tweaks here and there, their underwater submersible can be zooming around in no time!  I thought you’d like to see a few of the images we’ve had sent to us over the years we’ve taught this project:

Okay, so after that last email we sent about substituting laundry whitener for sugar, we received a flurry of emails, asking for more specific directions!  Well, here they are…

Grow beautiful crystals using laundry soap! In an OLD saucepan (like one you only use for science experiments), add a few cups of water and enough borax so that you can’t dissolve any more borax into the water (you”ll see sediment particles on the bottom of the pan). Turn on the heat to medium and stir with an OLD spoon (again, from your science tools) and when the sediment disappears, add a bit more borax… and stir… and when that disappears, add a bit more borax… and stir… and when that disappears… you get the idea!

You’re creating a super saturated solution here. When you can’t dissolve any more borax to the solution, and a bit of water and turn off the heat. Let cool to 130 deg F and pour into awaiting glass pickle jar. Balance a pencil across the mouth of the jar and suspend either a length of string or a pipe cleaner twisted into interesting shapes (like a snowflake, or a dog, etc…) Leave for about 6 hours and then check back. Crystals will grow to full size overnight if you’ve set up your solution just right.

Keep your eye on it, though, because these crystals not only grow quickly, but once the crystals from the pipe cleaner touch the ones growing on the sizes of the jar, you won’t be able to extract your shape! (Unless, of course, you want to grow a geode…)

Turning your kitchen table into a Mad Scientist Laboratory!

Chemistry is an exciting subject for kids of any age, especially if you set up a natural discovery environment for them to safely explore in. Let’s find out how to do this with your own homeschool science learning environment.

At a university, one of the first things you will learn about in your chemistry class is the difference between physical and chemical changes. An example of a physical change happens when you change the shape of an object, like wadding up a piece of paper. If you light the paper wad on fire, you now have a chemical change. You are rearranging the atoms that used to be the molecules that made up the paper into other molecules, such as carbon monoxide, carbon dioxide, ash, and so forth.

How can you tell the difference between physical and chemical changes? There’s an easy way to tell if you have a chemical change: if something changes color, gives off light (like the light sticks used around Halloween), heat is absorbed (gets cold) or produces heat (gets warm). Some quick examples of physical changes include tearing cloth, rolling dough, stretching rubber bands, eating a banana, or blowing bubbles.

Let’s mix up chemicals that bubble, ooze, freeze, and change colors. Before we start, you’ll need to get these items together: a muffin cup baking tray, water, vinegar (acetic acid), baking soda (sodium bicarbonate), washing soda (sodium carbonate), rubbing alcohol, hydrogen peroxide, citric acid, ammonium chloride (don’t activate the cold pack, but instead cut open and empty the contents into a plastic bag and discard the water pouch inside), aluminum sulfate (“alum” in the spice section of the grocery store or drug store), a head of red cabbage and a clear liquid dish soap such as Ivory.

Cover your kitchen table with a plastic tablecloth (if you have small kids, put another tablecloth on the floor to catch the spills). Place your chemicals on the table. A set of muffin cups make for an excellent chemistry experiment lab. (Alternatively, you can use empty plastic ice cube trays.) You will mix in these cups. Leave enough space in the cups for your chemicals to mix and bubble up – don’t fill them all the way when you do your experiments!

Shopping List:

• Rubbing alcohol (largest bottle)
• Hydrogen peroxide (largest bottle)
• Baking soda (largest box you can find)
• Distilled white vinegar (largest size)
• Washing soda (near the laundry soap)
• Citric acid (optional, but nice to have)
• One head of red cabbage
• Clear ivory dish soap (small bottle)
• Alum (check the spice section)
• Single-use cold pack ( not the gel kind)
• Plastic zipper bags and old water bottles
• Muffin cup baking tray (12 cups or more)

Set out your liquid chemicals in easy-to-pour containers , such as water bottles (be sure to label them, as they all will look the same): alcohol, hydrogen peroxide, water, acetic acid, and dish soap (mixed with water). Set out small bowls (or zipper bags if you’re doing this with a crowd) of the powders with “scoopers” made of the tops of your water bottles. The small “scoopers” regulate the amounts you need for a muffin-sized reaction. Label the powders, as they all look the same.

Although these chemicals are not harmful to your skin, they can cause your skin to dry out and itch. Wear gloves (latex or similar) and eye protection (safety goggles), and if you’re not sure about an experiment or chemical, just don’t do it. (Skip the peroxide and cold pack if you have small kids.)

What about the red cabbage? Red cabbage juice has anthocyanin, which makes it an excellent indicator for these experiments. Anthocyanin is what gives leaves, stems, fruits, and flowers their colors. Did you know that certain flowers like hydrangeas turn blue in acidic soil and turn pink when transplanted to a basic soil? This next step of the experiment will help you understand why. You’ll need to get the anthocyanin out of the cabbage and into a more useful form, as a liquid “indicator”.

Prepare the indicator by coarsely chopping the head of red cabbage and boiling the pieces for five minutes on the stove in a pot full of water. Carefully strain out all the pieces (use a fine mesh strainer) and the reserved liquid is your indicator (it should be purple).

When you add this indicator to different substances, you will see a color range: hot pink, tangerine orange, sunshine yellow, emerald green, ocean blue, velvet purple, and everything in between. Test out the indicator by adding drops of cabbage juice to something acidic, such as lemon juice and see how different the color is when you add indicator to a base, like baking soda mixed with water.

Have your indicator in a bottle by itself. Old soy sauce bottles or other bottles with a built-in regulator that keeps the pouring to a drip is perfect. You can also use a bowl with a bulb syringe, but cross-contamination is a problem. Or not – depending if you want kids to see the effects of cross-contamination during their experiments. (The indicator bowl will continually turn different colors throughout the experiment.)

Your mission: To find the reactions that generate the most heat (exothermic), absorb the most heat (endothermic), and which are the most impressive in their reaction (the ohhhh-ahhhhh factor).

The Experiment: Start mixing it up! When I personally teach this class, let them have at all the chemicals at once (even the indicator), and of course, this leads to a chaotic mix of everything. When the chaos settles down, and they start asking good questions, I reveal a second batch of chemicals they can use. (I have two identical sets of chemicals, knowing that the first set will get used up very quickly.)

Tip for Testing Chemical Reactions: Periodically hold your hand under the muffin cups to test the temperature.

After the initial burst of enthusiasm , your science students will intrinsically start asking better questions. They will want to know why their green goo is creeping onto the floor while someone else just bubbled up hot pink, seemingly mixed from the same stuff. Give them the change to figure out a more systematic approach, and ask if they need help before you jump in to assist. Use the indicator both before and after you mix up chemicals, and you will be surprised and dazzled by the results!

In this blog article, I mentioned how you could measure the speed of light the easy way.  Did you know there is an even EASIER way to do it?  Check out this super-easy method – all you need is a microwave and food.

And I promise to share with you how to do it the hard way in Part 3.

Being green is red-hot right now, so it’s not surprising how many emails we get asking how kids can do ultra-cool science fair projects on alternative energy.  One of the best ways to start is to visit a toy store and pick up a kit that has a solar cell, solar motor, and propeller combination.  Once you have these items, it’s easy to power things like race cars, solar boats, etc.  Here are a few images from our own Solar Power science fair project kit to get you started on ideas:

Take advantage of the process of crystallization to make candy!  You’ll create a super saturated solution of sugar and use it to grow your own homemade sugar candy crystals. (A super saturated solution is one that has as much sugar dissolved in the water as possible.  Note- if we didn’t heat the water, we’d wind up with only a saturated solution.)

Boil three cups of water in a large pot on the stove.  Add eight cups of sugar, one cup at a time, slowly stirring as you go.  The liquid should be thick and yellowish.  Turn off the heat and let it sit for four hours (or until the temperature is below 120 degrees F).  Pour the sugar water solution into clean glass jars and add a couple drops of food coloring (for colored crystals).  Tie a string to a skewer, resting the skewer horizontally across the jar mouth.  Let sit for a few weeks to a few months.

What kind of questions can you ask about this project? What happens when you vary the amount of water?  Sugar? Time? Seed or not to seed the stick?  Does it really matter how warm the environment is?  What if you don’t heat the solution to dissolve more?  Can  you color the crystals?  Why does the color stick (or not)? Does salt work instead of sugar? How about epsom salts? Does laundry detergent work, too?

The images below are sugar crystals, ammonia, and copper crystals.

If you have a relay from Radio Shack (Part #275-206 or similar), you can quickly form it into a buzzer with a DC power source. Remove the plastic housing so the connections are exposed (and you can clearly see which terminal is connected where.

Connect one coil terminal to ground (black battery wire), the other coil terminal to a place that connects to the clicker when not powered (rest position).  Connect power (the red wire) to the clicker.

Can you find the spot where you get a nice zap when you touch it with your fingers? (Note – you may need more than 3V to make this work with your particular relay.  Try 9 or 12V.)

Lay a row of naked straws parallel to each other on a smooth tabletop. Place two empty soda cans on the straws about an inch apart. Lower your nose to the cans and blow hard through the space between the two cans and *clink* they should roll toward each other and touch!

Why does this happen? When air moves, the pressure decreases. This creates a lower (relative to the surrounding air) air pressure pocket right between the cans. Recall that higher pressure pushes, and thus the cans clink together. Just remember – whenever there’s a difference in pressure, the higher pressure pushes.

What kinds of questions can you ask about this project?  For example: What types of cans work and don’t work?  How much air pressure you you really need – would a hair dryer be a better choice?

So this is a more advanced project… and one that takes patience.  There is an easy way and a hard way to do this project.  I particularly like the hard way better, because there’s more observational science involved and less mathematics.  But let’s start with the easy way first.

Easy Method for Measuring the Speed of Light In a transparent tupperware, make a batch of clear gelatin (like jell-o) and let it harden.  Skimp on the water so the mixture is very firm.  When ready, take it out of the fridge and shine a laser beam through the side of the tupperware… you’ll see the beam ‘bend’.  Carefully measure the angles of incidence and refraction and use Snell’s law to back-calculate the speed of light.

For reference, the index of refraction for ice is 1.31; for water at 20 deg. C is 1.33; for diamond it’s 2.42; for plexiglass it’s 1.51.  For your measurement to be completely accurate, you’ll need to remove the tupperware and measure it for the gelatin.

…to be continued…