Fuel Heats

Calorimetry and Fuels

Question: What does it mean to have an “octane” level when you pump gas? How is one fuel more effective than another? The connection to burning fuels to heat one's home or fuel one's car or even body might be connected here. What foods do you eat when you want a great deal of energy?

Exploration Overview: Experimentally, a student can weigh a small piece of nut, wood, or food and light it with a butane lighter. The burning source can be supported by a pin or folded paper clip. The heat can be collected in a test tube of water and measured with a thermometer. The gain in temperature of a known amount of water can give the caloric output of the burned food or fuel.

Simple Procedure:

1. Select two small samples of wood, such as pine and oak. They should be the same size. Place them on the pin or paper clip so they will burn easily under a test tube of water,

2. Place the sample to be burned on a aluminum plate or similar surface so that any ash or burning ember can be caught.

3. Fill a test tube with an amount of water (20 ml) is adequate.

3. Use a test tube holder to keep the bottom of the tube above the flame. The hottest part of a flame is the top third, so adjust however the test tube is held so it contacts the flame as efficiently as possible.

3. Measure the temperature of the water before the experiment. It should be room temperature. We want any temperature change to result from the burning of the fuel, not the environment.

4. Get the wood burning by using a butane lighter.

5. As long as the wood burns, collect as much heat as possible in the tube.

6. When the flame is out, measure the temperature of the water.

7. Collect the initial and final temperatures of the water for each sample.

8. If the water increases more temperature in one experiment than another, then more heat is produced and therefore stored in the fuel.

9. Students can describe the difference between fuels and their efficiency. How fast do pines grow? How fast does oak grow?