Lesson 4: Heat and the Sun


Activity 1: The First Law of Thermodynamics

Materials: ScienceWiz Energy box, black marker, note cards (kit), tea candle (kit)
Thermodynamics means moving heat. Scientists have come up with three laws that govern energy and heat (a form of energy).
Law #1
Energy cannot be created or destroyed, but it can be changed.
Read the bottom of pages 13-17 in the book found in your ScienceWiz Energy box. The book presents a variety of ways to change energy from one form to another. Conduct the experiments described using the materials in your kit.
Before your child begins her lab, ask her to look at the materials on the top of the page 14. Then ask her to answer questions 1 through 4. When she finishes the lab, ask her to explain how each investigation changed energy from one form to another. NOTE: Be available to assist your child with the experiments involving fire. The last demonstration requires a sunny day. If today is not sunny, your child can try the demonstration on a day that is sunny.

Activity 2: The Second and Third Laws of Thermodynamics

Materials: 3 glasses or cups
Law #2
Heat energy always moves from hot things to cold things.
To observe this phenomenon, fill three glasses with water. Make the first glass very cold, the second as warm as you can without hurting yourself when you touch it, and the third comfortably warm. For three minutes put your right index finger in the cold water and the left index finger in the hot water. After three minutes remove both fingers and put them in the warm water. What happened?

You probably noticed that the finger that had been in the cold water got warmer, and the finger that had been in the hot water got cooler. Heat from the finger that was in the hot water traveled from your hand to the water, so your finger felt cold. The heat from the warm water traveled to the finger that had been immersed in cold water, so it felt warmer.
Law #3
You cannot have anything colder than absolute zero
(−273.15 degrees C / −459.67 degrees F).
When your child finishes her experiment, ask her how the investigation reinforced the second law of thermodynamics.