Engineering Catapults

In order for the teacher to assess and activate prior knowledge, they will ask the following questions:

• What is energy?
• What is potential energy?
• What is stored energy?
• What happens when force is acted upon an object? Does it move or does it stay still?

1. Based off of the students answers to this question will determine how deep the teacher explains these concepts. The teacher will display the definition of energy, potential energy, and stored energy on the board and create a small discussion around the words.
2. The teacher will then have students line up to go outside for an activity.
3. Once outside, the teacher will place a piece of tape on the ground to make a line. Students will stand behind the line and kick a soccer ball. Each student will have a turn and will mark where the soccer ball landed after they kicked it. The students notice the distance that the ball went based off of the energy that they used to move the soccer ball from sitting still to another location.
4. The students will go back inside after this. Once the students are inside the teacher will separate the students into groups of two to create catapults. They will start by being given four popsicle sticks, one bottle cap, ten rubber bands, a glue stick, one piece of candy corn, one skittle, one eraser, and one cotton ball.
5. The teacher will provide an example of what a catapult could look like but students will be encouraged to create their own catapult using their creativity.

Problem: Creating a catapult that catapults objects that are used the furthest distance. It is a problem because we are trying to figure out what way you can create the most efficient catapult to use the most potential energy that then turns energy in motion. The teacher will explain that engineers that use catapults are engineers who are interested in all things to know about energy!
Questions students should ask themselves:  
-Which item will go the furthest? Why?
-Can you design a different catapult using the same materials but in a different way to catapult the items further?
     6. Students will then start by predicting which object will go the furthest and then explain why they believe that that item will go the furthest.
     7. Students will create their catapult (with teacher assistance if needed) and then test their predictions by catapulting their items one at a time.
     8. Students will record their data.
     9. After this data is recorded, students will come together and discuss what item went the furthest and why they think that this happened.
    10. Students will then be given 8 popsicle sticks and told to create another catapult and will be encouraged to create a different catapult than the first to see which one projects the items the furthest.
    11. After the students have created their second catapult, they will then predict which object will go the furthest and explain why they believe that that item will go the furthest.
    12. Students will record their data and compare their data, with their partner, about which catapult worked the best and why they think that that specific catapult worked the best.
    13. Students will then come together with the teacher and discuss their results.

Guided Questions for discussion:

• Which catapult worked the best?  The one with 4 popsicle sticks or the one with 8? Why do you think that?
• Which item went the furthest? Why do you think that?
• Which item didn’t work well at all? Why do you think that?
• The further that you pulled back the catapult, the further that the item went?  Why do you think that?  Do you think that this has anything to do with energy?
• Explain to me how potential/stored energy is used in this experiment.
• Explain to me how your force can determine the distance that the time.

When you pull back the popsicle stick, you are building up your potential/stored energy by bending it back.  As you release your object, that energy that was one not moving is now in motion because of the force that acted upon it.  If the students can explain this to the teacher, you will know that they have achieved the lesson objective.  The teacher will be able to understand whether or not students have understood this concept based off of the discussion that the students have throughout the activity.  The teacher will ask the students guiding questions and the answers that the students give the teacher will help the teacher determine if the students grasped the concept.  This portion is embedded throughout the lesson because this discussion happens after the first catapult has been built and then it happens at the end of the lesson because the discussion happens after the second catapult has been built and the students have the opportunity to compare the results. This assessment style is formative because the teacher is assessing the students’ understanding throughout the entire lesson by the way they participate in engineering the catapults and how they analyze their results.