How to Make a Calorimeter Out of Styrofoam Cups

A calorimeter is a machine used in the chemistry lab to measure the heat flow generated by a reaction. The two main types of calorimeters are the coffee cup calorimeter and the bomb calorimeter. A coffee cup calorimeter is made from a Styrofoam coffee cup and a thermometer that fits through a hole in the lid. Building a calorimeter isn't tough, but using it correctly--well, that's another story.

Things You'll Need

• 1 Styrofoam coffee cup
• 100 ml distilled water
• 1 cardboard circle, slightly larger than the cups
• Scissors or utility blade
• 1 thermometer
• 1 rubber band
• 1 ring stand
• 1 clamp
• 5 g calcium chloride

Instructions

1. Measure 100 ml water and transfer it to the Styrofoam cup.

2. Make a hole in the center of the cardboard large enough for the working end of thermometer to be inserted.

3. Pull the thermometer through the cardboard. Bring it far enough through to be submerged in the water without touching the bottom.

4. Secure the thermometer by wrapping a rubber band around the portion that extends beyond the lid, just above the surface of the cardboard. This will prevent the thermometer from slipping while your work.

5. Place the lid on the calorimeter, and set the calorimeter on the base of a ring stand. Additional support can be given to the thermometer by attaching a clamp. Leave enough room to swirl the cup without bumping the thermometer.

6. Record the temperature of the water before adding anything.

7. Lift the lid, keeping the thermometer in the water, and add the calcium chloride.

8. Shut the lid and gently swirl the cup, pausing every 20 seconds to record the temperature from your thermometer.

9. Stop swirling after 3 minutes. The change in the water temperature is a measure of heat that the water has absorbed.

Tips & Warnings

• When using a calorimeter, you have to assume your machine is perfect, when, in fact it is not. Some heat is lost through the lid. Heat flow can be calculated using the following formula: q = (specific heat) * m * ΢t, where q = heat flow, m = mass in grams, ΢t = the change in temperature, specific heat = the amount of heat required to raise the temperature of 1 gram of a given substance 1 degree Celsius. The specific heat of water is 4.18.

Resources

• Wise Geek: Brief and Straighforward Guide to Calorimeters