1. Motion and Design Lesson 6 Evaluating Vehicle Design: Looking at Rubber Band Energy

2. Materials Record Sheet 6-A: Evaluating Our Vehicle Design for Rubber Band Energy per student Record Sheet 6-A: Evaluating Our Vehicle Design for Rubber Band Energy per student Standard Vehicle per group Standard Vehicle per group 3 rubber bands per group 3 rubber bands per group

3. Overview Have explored the motion of your vehicles when pulled by a weighted string. Have explored the motion of your vehicles when pulled by a weighted string. Will explore another way to move your vehicle by releasing the energy stored in a stretched rubber band and using it to turn an axle. Will explore another way to move your vehicle by releasing the energy stored in a stretched rubber band and using it to turn an axle. Will test various ways your rubber band can be used to move your vehicle. Will test various ways your rubber band can be used to move your vehicle. Will discuss the results of your evaluations. Will discuss the results of your evaluations.

4. Background Energy – capacity for doing work Energy – capacity for doing work Sources of energy Sources of energy Suns energy warms the Earth and enables plants to grow. Suns energy warms the Earth and enables plants to grow. Wood and coal provide chemical energy that is used for heating homes and businesses. Wood and coal provide chemical energy that is used for heating homes and businesses. Wind energy turns windmills and moves sailboats. Wind energy turns windmills and moves sailboats. Our bodies use the energy stored in food. Our bodies use the energy stored in food. A flashlight uses energy stored in batteries. A flashlight uses energy stored in batteries. A car uses energy stored in gasoline. A car uses energy stored in gasoline.

5. Energy exists in many forms. Stored energy or potential energy – energy ready to be released. Stored energy or potential energy – energy ready to be released. In lesson 3, you stored energy in the weight on the string when you raised it from the floor to the height of the work space. In lesson 3, you stored energy in the weight on the string when you raised it from the floor to the height of the work space. When you released the weight, gravity pulled it to the ground and the string pulled the vehicle along the work space. When you released the weight, gravity pulled it to the ground and the string pulled the vehicle along the work space. As the weight descended, its stored energy was converted to the energy of motion of both the weight and the vehicle. As the weight descended, its stored energy was converted to the energy of motion of both the weight and the vehicle. Physicists call the energy of motion kinetic energy. Physicists call the energy of motion kinetic energy.

6. In this lesson… Will evaluate the effectiveness of your vehicles’ design when it is driven by the energy stored in a stretched rubber band. Will evaluate the effectiveness of your vehicles’ design when it is driven by the energy stored in a stretched rubber band. If you hold the ends of a rubber band and pull your hands slowly apart, the rubber band lengthens, but you can also feel it pulling your hands back in. If you hold the ends of a rubber band and pull your hands slowly apart, the rubber band lengthens, but you can also feel it pulling your hands back in. When you wind the rubber band around the axle of your vehicle, you store energy in the rubber band. When you wind the rubber band around the axle of your vehicle, you store energy in the rubber band. When store energy is released, it changes form. When store energy is released, it changes form.

7. Example of stored energy When an archer pulls back on a bowstring, the bow bends and the string stretches. When an archer pulls back on a bowstring, the bow bends and the string stretches. The archer has stored energy in the bow and string. The archer has stored energy in the bow and string. When the archer releases the arrow, the stored energy is transformed into the motion of the arrow. When the archer releases the arrow, the stored energy is transformed into the motion of the arrow. Likewise, the wound-up rubber band on the vehicle’s axle has stored energy. Likewise, the wound-up rubber band on the vehicle’s axle has stored energy. When you release your vehicle, the rubber band unwinds and the stored energy is converted to the vehicle’s energy of motion. When you release your vehicle, the rubber band unwinds and the stored energy is converted to the vehicle’s energy of motion.

8. You have observed how your vehicle can move with rubber band energy. You have observed how your vehicle can move with rubber band energy. When you twisted the rubber band, the amount of energy stored in the rubber band increased. When you twisted the rubber band, the amount of energy stored in the rubber band increased. When you released the vehicle, the stored energy caused the axel and the attached wheels to spin and the vehicle to move. When you released the vehicle, the stored energy caused the axel and the attached wheels to spin and the vehicle to move.

9. Getting Started Put on your goggles. Put on your goggles. Get your standard vehicle. Get your standard vehicle. Get the connected rubber bands. Get the connected rubber bands. Take a couple of minutes to explore how you might use the connected rubber bands to move your vehicle. Take a couple of minutes to explore how you might use the connected rubber bands to move your vehicle.

10. Do the investigation and complete the sheet.

12. Discussion What did you feel in your hand as you wound the rubber band? What did you feel in your hand as you wound the rubber band? Did this feeling change as you wound the rubber band tighter? If so, how? Did this feeling change as you wound the rubber band tighter? If so, how? Did the direction in which you wound the rubber band affect the direction in which your vehicle traveled? If so, how? Did the direction in which you wound the rubber band affect the direction in which your vehicle traveled? If so, how?

13. Discussion What did you do to make your vehicles move a longer distance? What did you do to make your vehicles move a longer distance? What did you do to make your vehicles move a shorter distance? What did you do to make your vehicles move a shorter distance? Do you know why this happened? Do you know why this happened? Return materials. Do not disassemble your vehicle. Return materials. Do not disassemble your vehicle.

14. Extensions Bring in advertisements for automobiles and trucks. Prepare your own advertisement promoting the special features of one of these vehicles. Bring in advertisements for automobiles and trucks. Prepare your own advertisement promoting the special features of one of these vehicles. Conduct research to find out how the design of the automobile has changed over time. Create a timeline to show these changes. Conduct research to find out how the design of the automobile has changed over time. Create a timeline to show these changes.

15. The End!!!