I am a high school teacher in Las Vegas and I found myself at the beginning of a new school year with a lot of ideas, but virtually no money to work with. As a result I had to become very thrifty, very quickly. So in the tradition of node your homework, here are some ideas to try in your classroom, or just at home.
The most expensive part of chemistry is trying to find chemicals and equipment. Many experiments call for chemicals that can be found in your local grocery store as long as you know where to look. Some of these you may already know, but I'm sure that there are a few suprises.
Acetic Acid - Vinegar
Acetone - Nail Polish Remover
Ascorbic Acid - Vitamin C
Ammonia - Window Cleaners
Bismuth Subsalicylate - Pepto Bismol
Calcium Carbonate - Tums
Calcium Hydroxide - Nair
Carbonic Acid - Tonic Water
Cyanoacrylate - Superglue
Ethylene Glycol - Anti-freeze
Iso-propyl Alcohol - Rubbing Alcohol
Magnesium Hydroxide - Milk of Magnesia
Muriatic Acid - Concrete Cleaner
pH Indicator - Red Cabbage Juice
Sodium Bicarbonate - Baking Soda
Sodium Hypochlorate - Bleach
Sodium Polyacrylate - inside Disposable Diapers
Toluene - Paint Thinner
As far as equipment is concerned, it is really all about the scale of your labs. For a small scale lab, you can use plastic pipettes for almost everything. In a classroom instead of setting out whole bottles of chemicals and worrying about cross contamination you can label and fill pipettes. That way you can have a set of chemicals for each lab group without having individual bottles. If you have access to different sized pipettes you can cut the bulb off the largest pipette and use the bulb as the container for your experiment.
For large scale experiments nothing beats a glass beaker, but if you can get away with using a plastic glass it's easier clean up and much cheaper. Kitchen measuring cups are also great as long as you know your conversions.
Here are a few fun experiments that are crowd pleasing and cheap.
Have your students answer the always intriguing question, "How much milk can I drink before I puke?" Most people don't realize that milk makes you puke when all of your stomach acid gets neutralized. Of course, no one should actually drink milk until they get sick. Your students can take about 10ml of acid and see how much milk can be added before neutralization happens. Milk is cheap, you can use red cabbage to show neutralization, and the whole thing can take place inside of a plastic cup! The acid in your stomach is hydrochloric, but vinegar can substitute for slightly less accurate results.
You can also show effectiveness of different antacids by taking several brands and finding how much acid gets neutralized vs antacid mass. These are excellent labs to use on students who think that chemistry has nothing to do with their lives.
Properties of Liquids
Students often struggle with the idea of defining what a liquid is. Add some water to corn starch and attempt to stir. Add water until it appears as a liquid but you can smack the top of it without much movement. This solution behaves as a solid with quick movements and a liquid with slow movements. The whole mixture is technically a liquid because it takes the shape of its container. If you are doing this with students let them play around with the mixture and ask them to determine its state of matter.
Capillary Action is one of those elusive properties that you can show in any container, but nobody cares about. Stick a stalk of celery in a cup with colored liquid in it and within a few hours/days the leaves will take on the color of the liquid it is in.
Surface Tension is great fun to experiment with if you have some mercury, but for the rest of us try this. Get some plain water and a mixture of one part liquid soap to four parts water. Stir well and allow bubbles to subside. Have the students add the liquids drop by drop to the top of the pennies. The students will notice that the penny with the soap water will hold a lot more drops before spilling over.
The idea that pressure and volume are related can be hard for students to visualize. Get a large clear bottle, at least 1 liter. In the bottom of the bottle put a couple tablespoons of baking soda. Put some acid inside of a test tube. Drop the test tube into the bottle so that the acid stays mostly inside of the test tube. Inflate a balloon inside the bottle and tie it off. The balloon should be wall to wall within the bottle. Place the cap on the bottle. When it comes time for the demonstration tip the bottle so that the acid spills out. As the acid and base react they will release CO2 creating more pressure inside the bottle. Due to the excess pressure the balloon inside of the bottle will seem to magically shrink!
I hope that this little list of cheap science tricks will help you entertain your friends, students, or heck even just your own drunk self! Enjoy!