Talk It Over

How do you make things hotter? What is heat? How do you measure heat? Are some liquids easier to heat than others?

Get

• Water (at room temperature)
• Jar
• Glass measuring cup, microwave safe
• Vegetable oil (at room temperature)
• Hot pad
• Digital instant-read thermometer*
• Access to a microwave oven

Go

1. The night before you start your experiment, set a jar of water and a container of oil on the countertop. By morning, they will be the same (room) temperature.
2. Measure ½ cup of water in the measuring cup. Measure and record the temperature.
3. Place the cup and water in the microwave. Heat at full power for 15 seconds. Measure and record the temperature of the water.



4. Repeat step 3 another seven times, recording temperatures for a total of 2 minutes of heating.
5. Clean and dry the measuring cup. Repeat steps 2–4 using oil.

Stay Safe

Avoid burns and spills. Get an adult's help in handling the hot cups and liquids.

Go Easy

Follow the "Go" procedure, but make measurements every 30 seconds instead of every 15.

Go Far

Specific heat is the amount of heat required to raise the temperature of 1 gram of a substance 1°C. Modify the "Go" procedure so you can calculate the specific heats of water and oil. (Hint: You will need to know the output of your microwave.) You might compare molasses, corn syrup, vinegar, and varieties of oil including corn and canola. Also, try comparing solutions such as sugar or salt water made in different concentrations (such as ¼, ½, ¾, and 1 teaspoon sugar or salt per ½ cup of water).

Show Your Results

Record temperatures in a data table like this for "Go Easy":

Make a bar graph that compares the two liquids.

For "Go," use the same kind of data table, but record temperatures in 15-second intervals. Make a line graph of temperature (on the vertical axis) by time (on the horizontal axis), using different colors of lines to compare water and oil.

For "Go Far," make data tables and line graphs that compare the specific heat values you determined. Look up published tables of specific heat values and see how your results compare.

Tips and Tricks

Don't use a digital thermometer from the health section of your pharmacy or discount store. It is meant for taking human body temperatures, so its range is too narrow for this experiment. Choose a thermometer from the kitchen aids department. It will measure the wide range of temperatures you need.

Many thermometers read temperatures in both Fahrenheit (°F) and Celsius (°C). You can use either for this experiment; just be careful not to confuse them. If you want to work as scientists do, use °C.

Keep the tip of the thermometer in the liquid. If it touches the container, you won't get an accurate reading. Like this:

Not like this:

This is a good experiment to repeat several times. Averages of your temperatures from multiple trials are better than the results of a single trial.

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CliffsNotes Parent's Crash Course Elementary School Science Fair Projects
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