Energy Transformation and “The Tale of Fern Fossil”

• Read together with students “The Tale of Fern Fossil” (S-4-5-2_Tale of Fern Fossil.pdf). Hand out to students the Tale of Fern Fossil Worksheet (S-4-5-2_Tale of Fern Fossil Worksheet.doc).

• Using the Energy Picture (S-4-5-1_Energy Picture.pdf) from Lesson 1, have students write a paragraph or two about the sequence of energy flow they see in this picture, starting with the Sun. This written sequence will reinforce the concept that the Sun is the primary source of all our energy on Earth. Using the rubric below, explain to students they will be assessed on how many examples of energy they identify and the transformations they can describe, starting with the Sun.

Energy Transformation and “The Tale of Fern Fossil” Writing Rubric

• Optional: Read “The Tale of Johnny Energy Seed” (S-4-5-2_Tale of Johnny Energy Seed.pdf)and draw a picture of the energy transformation from seed to other energy forms or write a summary paragraph stating how many energy forms are found in the story.

This lesson is divided into two parts. Part 1 investigates how energy moves from object to object, or how energy is transferred from one object to another. Students can spin off their own examples and demonstrate these to the class. Part 2 investigates how energy is transformed or changed into other energy forms. Although this concept may seem abstract, students are exposed to examples of energy transformation every day and can share examples in their group work.

Part 1: Pass Your Energy Along!

Open the lesson by leading the students through an activity designed to stimulate interest about the flow of energy.

Step 1: Ask the class if it is possible to pass on energy. Inform students that the next activity will give them an example of how energy can be passed from one object to another. Divide the class into partners or small groups and give each group five nickels. Tell students to place four of the coins in a row on a smooth table so they are touching one another. Lay the fifth coin 2 inches (5 centimeters) away from the end of the row. Flick this coin sharply with your finger so it slides across the tabletop and hits the fourth coin in the row. Have the groups take turns flicking the coin. After ample time, ask volunteers to explain what happens.

What Happens: When you flick your finger, you pass some of your energy to the fifth coin. Your energy makes the fifth coin move and hit the row of four. When this happens the energy is passed to the fourth coin in the row and stops. The fourth coin moves a little and passes the energy to the third coin, which passes the energy to the second coin, which passes the energy to the first coin. The first coin uses the energy to move and slide across the table. Your energy passes through every single coin.

Step 2: Ask students to make a prediction as to what will happen when two coins are used to flick against a row of three. Allow students to test their predictions and conclusions.

Step 3: Reinforce that energy is transferred or moved from one object or place to another. “This is an example of how energy flows. When a burner on your stove is hot, the heat, or thermal energy flows or is transferred from the burner to all matter around it like the pan or the person holding it. Another example is when a moving object strikes a nonmoving object and causes it to move. When that happens, the energy from the moving object is transferred to the nonmoving object. As you can see there are different forms of energy, each with a unique way of transferring itself from one form to another.”

Step 4: Remind students that energy has many forms like mechanical, thermal, radiant, and electrical. Explain that these forms of energy can be placed into one of two groups: kinetic or potential. “Here are some examples of potential and kinetic energies.” Have students create a new KWL page in the science journals and add the following terms to their W sections. Write the definitions for the whole class to see in order to copy the definitions down in their journals:

• Potential energy: Stored energy. It is the energy that exists within an object. It is the stored energy of position possessed by an object.

• Stored Mechanical: The energy which is possessed by an object due to its stored energy of position. Rubber bands and springs are good examples of stored mechanical energy.

• Nuclear: Energy locked in the nucleus of the atom. Nuclear power plants split atoms in a process called fission.

• Chemical: The energy stored in food, wood, coal, petroleum, and other fuels.

• Gravitational: Energy stored as a result of gravitational forces concentrated by the earth for the object. Water held back by a dam is an example of gravitational energy.

• Kinetic Energy: Energy of motion. When you are walking or running, your body is exhibiting kinetic energy.

• Electricity: Energy produced when something upsets the balancing force between electrons and protons in atoms.

• Light or Radiant: Waves that emit energy. Examples include radio and television waves, gamma rays, and x-rays.

• Heat or Thermal: Created by heat. The hotter an object becomes, the more thermal energy it possesses.

Step 5: Also remind students that the primary source of Earth’s energy is the Sun or solar energy (as radiant or light energy, not as heat or thermal energy. The Earth is too far away from the Sun for thermal energy, but the light or radiant energy causes thermal energy on Earth.) Solar energy provides the Earth with its main source of energy, which is transformed into other forms of energy:

• wind: moving air created by unequal heating on the Earth’s surface

• chemical: the sun provides energy for all food we eat

• solar energy: energy relating to or derived (from) the sun.

Step 6: Tell students that all energy comes from a source and can change from one form to another. Refer back to the last lesson and ask students to identify where the energy came from that allowed them to run in place for a minute (food). Continue the discussion by asking where the energy came from to produce food. (sun)

Tell students that this next lesson will demonstrate how energy is passed from one object to another, and how energy can change from one form to another.

Part 2: Changing Energy

Explain to students that just as they saw with the coins, not only can energy be passed along from their hands to the coins, but also it can change into different forms (mechanical to heat/thermal energy).

Pass out rubber bands and have students touch a new rubber band to their lips. “Does the rubber band feel cool or warm?”

Next have students stretch the band quickly several times and then gently touch it to their lips. They should feel the heat (thermal energy) caused by the friction of stretching it, and then feel the heat go from warm to cool in a matter of seconds once the stretching stops. Explain how thermal energy is really the energy of moving particles. The more thermal energy a substance has, the faster its particles move, and the hotter the substance becomes. (Note: This is also a good example of potential and kinetic energy. It is potential energy when the rubber band is not stretched and energy is stored; it is kinetic when it is stretched and let go in motion.)

Explain or demonstrate to students when thermal energy (like a hotplate) is added to water, the water becomes hotter and its particles move faster and faster until it reaches the boiling point, and then becomes steam. Conversely, if we remove thermal energy, we can cool water, and the more thermal we remove, the slower the particles move until the water becomes a solid—ice.

Furthermore, explain to students that the stored chemical energy in their bodies (fat) allowed them to stretch the rubber band (mechanical energy) and produce a tiny bit of thermal energy.

Write on the board or overhead transparency that the energy from one piece of toast will allow you to jog for 6 minutes, bicycle for 10 minutes, walk for 15 minutes, sleep for 1.5 hours (yes, it does take energy to sleep!), or lift a bag of sugar 21,000 times. What would happen if you ate TWO pieces of toast?

Finish up the lesson by evaluating students’ comprehension of the lesson by having them write down one of the following statements on a sticky note and then place it on the door on their way out. Students will not put their names on these evaluations to provide anonymity. These notes will provide the teacher with an informal evaluation of the lesson.

a) I fully understand how energy moves and is transformed.

b) I mostly understand how energy moves and is transformed but still have questions.

c) I only understand how energy moves.

d) I only understand how energy is transformed.

e) I don’t understand how energy moves or is transformed and need help.

f) I need a tutor to explain it again.

Extension:

• To reinforce the concept of thermal energy in motion and transferring it from one object to another, try this simple activity. To reinforce the transfer of energy, have students rub their hands to make them hot, and then touch their face. “What happens? The warm hands warm the face. Why? Heat moves from hot to cool.”

• Now have students cool their hands down by wiping them with a damp paper towel (a little ice would even be better). Ask students why they think this transfer of thermal energy happens. “What happens if they rub their hands again and touch their face?” Thermal energy is transferred back and forth from hands to face, face to hands, and so on. What caused their hands to get warm? (friction). The mechanical force of friction produces thermal energy.

• Have students complete the Energy at Home Worksheet (S-4-5-2_Energy at Home Worksheet.pdf) for homework and to identify energy sources at home.