Science Buddies: "Ask an Expert"

Hey all,

First of all, may I say...I wish I'd found this site years ago, it's a great idea!

I'm to make a calorimeter that will measure the most accurate heat of solution (we're using water and NaOH). We can use any materials we want, but can't bring in two styrofoam cups taped mouth-to-mouth (shame, isn't it?). Ideally, it will have an agitator to mix the solution and a way to take the temperature without lifting the lid.

Currently, I'm thinking of using a small tupperware container to hold the solution and spraying the outside with spray-foam insulation, drilling a hole in the lid for the thermometer. I can't imagine why this wouldn't do, but are there any other ideas I can use? Other materials I've considered are sawdust, block styrofoam, duct tape, shredded paper etc.

How can I make an agitator? I'm thinking about twisting some wires tightly together at the top and leaving them free at the bottom, shoving this through a small hole in the lid (the agitator also preferably does its job without lifting the lid).

Lastly...we're to find the "R value" or the specific heat capacity of the materials used to create the calorimeter. How in the world do I do this?

Thanks very much for any and all help.

Hi Laura!

If you pose "how do I make a calorimeter?" to answers.com, you get a wealth of resources. Many of the top ten hits look appropriate, so please pick what works for you.

P.S.: If you pose "How can I make an agitator?" whole different results came out. Try it out! One needs to be more clever. I tried "How do you mix liquids?," but that wasn't satisfactory. Maybe, you'll come up with the magic formulation. Good luck!

Some precautions: Sodium hydroxide reacts with a lot of stuff including aluminum and copper alloys, so your choice of tupperware looks good to me.

I'm not sure what Tupperware is made of..probably polypropelene or high density polyethylene. You should be able to look of the composition and determine the specific heat.

you can probably use a plastic soda straw as a stirrer...split the end and bend it into a propellor.

It reacts with skin and flesh..very bad in the eyes.
I'd wear a face shield and protective clothing (a raincoat and rubber gloves?) to protect against splashes.