thermodynamics

Melting Pennies

I am fascinated by the chemistry of pennies. I have tried several experiments found in the Journal of Chemical Education.

How do you teach "entropy" to high school students?

I was recently drawn to an article published ASAP in JCE entitled Application of the Second Law of Thermodynamics To Explain the Working of Toys. Erick Castellon wrote the article highlighting the use of three toys that are used to help students develop an understanding of the second law of thermodynamics and entropy by having them observe the working of the toys and the energy transfers that occur while playing with them. I already had two of the toys, the radiometer and the drinking bird. I ordered the stirling engine from the link provided in the supporting information. As I waited for the stirling engine to arrive from Japan (which was only a few days) I attempted to write an activity to guide my students to conceptual understanding as they worked with the toys.

Pyrex by any other name...

Did you know that Pyrex glassware used in chemistry labs is different than Pyrex glassware used in kitchens? Pyrex glass used in chemistry experiments is made of borosilicate glass, whereas the Pyrex used when baking is made of soda lime glass. What’s the difference?

Some Like It Hot, Some Like It Cold

In this Activity, students combine liquids in a calorimeter and use a thermometer to determine if the reaction mixture gets hot or cold. All of the chemicals (yeast, hydrogen peroxide, vinegar and baking soda) except ammonium nitrate, are available in supermarkets.

Calories - Who's Counting?

In this Activity, students determine how many calories are released per gram when marshmallows and cashews burn and then compare the quantity of energy available from carbohydrates versus fats. Students burn the food items beneath a metal soft drink can containing water and measure the resulting change in temperature of the water.

Cool! Rates of Heating and Cooling

In this Activity, students measure the rate of warming for a chilled thermometer bulb held in room temperature air, for a chilled bulb held between two fingers, and for a few milliliters of ice-cold water. Students discover that the warming process is not linear. This Activity emphasizes the importance of measuring temperature change and its relevance to other experiments.

Hold the Heat: Global Warming and Calorimetry

In this Activity, students perform quantitative calorimetric measurements on samples of ice/water heated by incandescent light bulbs and/or convection with room-temperature surroundings. They measure and graph temperature as a function of time.

A Candle in the Wind

In this Activity, students investigate physical changes that occur in a candle to learn how a candle functions and how you can blow it out. This Activity is based on a series of lectures presented by Michael Faraday in the 1850s.