Engagement (5 minutes)
Show video clip of NASA's Newton's Second Law
1. Ask students orally, "How do you think mass affects a force?"
2. Ask students orally, "How do you think acceleration affects a force?"
Explore (30 minutes)
1. Assign roles for teams of four students.
- Principal Investigator: This is the spokesperson for the group and is allowed to ask the teacher questions when the group has a question.
- Materials Manager: This person is responsible for getting all materials for the project and is the only person allowed out of their seat. This person is responsible for returning any equipment or supplies.
- Task Manager: This person keeps the group on task.
- Checker: This person makes sure everyone is writing down everything correctly and that everyone is following appropriate lab safety.
2. Provide teams with handout on how to set up the Newton Car and data sheet. You just have to give them the last two pages of the handout. The first two pages just provide background information for the teacher.
3. Clear areas for each team to set up their experiment.
4. Provide a station where teams can fill their bottles with different materials to change their total mass. Place the popcorn seeds, washer, etc. in different bowls for easy access. The bottles do not have to be filled to the top. However, the rubber bands should be positioned around the approximate center of mass of the bottle to get a uniform toss.
5. Check each team to ensure they are being consistent with procedures. For instance, placing straws differently for each test would introduce a new variable into the experiment that could affect the results.
Tip: Provide masking tape so that students can use small tape pieces to mark the positions of the straws for consistency.
Explain (10 minutes)
Ask the students orally, "How did mass affect how far the car moved?"
Ask students, "What kind of trends did you see with your graph in the lab?"
Tell the students to think a minute on their own and develop an equation to show the relationship between mass and acceleration.
To guide students in their development of the equation, have them think about how a train (which has a large mass) hitting a vehicle would have an effect on force of impact compared to a smaller car hitting the same object. Also, ask the students to think about how one car accelerating faster than another car would have an effect on force of impact.
Pair the students with a partner, and have them compare their equations they developed to see if they are the same or different. Then have the students share their equations orally as a group. Compare their equations as groups. Students should be able to defend their answers orally for the equation they developed using the examples of a train vs. a smaller car on force of impact, and they should use the example of two similar cars in mass but with different velocities.
Finally, explain orally to the students that there is a relationship, and it is: Force = mass x acceleration. This will allow for students to check their answers.
Elaboration (10 minutes)
Think Pair Share
1. Have students individually come up with an example of Newton's Second Law in real-life or when they have experienced Newton's Second Law.
2. Have students share with a partner their example.
3. One person from each pair shares the group's example. Write the list of examples on the board for the students.
4. Have students complete an exit ticket. Students should list 3 things they learned from lesson and one thing they still need help with. Have students also reflect on how they performed with their roles (eg: Principal Investigator, Materials Manager, Task Manager, Checker). Students should list one thing they did well as a group and one thing they can improve upon.
