Daisy Mechanical Engineering: Model Car
According to the Badge Explorer, in doing this badge, Daisies will build a model car and test the friction of their car on different surfaces to prepare for a Troop Car Chase!
Daisies are supposed to:
- Design and build model cars
- Use model cars to test the friction of different surfaces
- Race your cars!
When you’ve earned this badge, you'll have learned about friction by building and testing model cars. You will know how to design and test new things that you invent.
What Does VTK Recommend?
Here are the activities described in the word-for-word scripts on VTK:
- Girls rolls different sizes/types of balls back and forth and make observations about the amount of force necessary with each type of ball
- Talk about rolling the balls and the force required. Discuss the concept of friction
- Draw a model car--point out that engineers draw their ideas first, then model them
- Build a model car
- Set up several friction stations--areas with different surfaces. Have the girls hypothesize about which one will allow the car to go the farthest. Test and record data
- Discuss results (end of meeting 1)
- Design a ramp and test it; how does changing the ramp change things?
- Have a contest to see whose car goes the furthest. Allow girls to redesign cars and try again.
Brownies: Mechanical Engineering: Race Car
The Badge Explores states that to earn this badge, girls need to "design, build, and test your own race car to explore how science can make a faster race car!"
Brownies are supposed to:
- Learn how design can affect speed
- Design and build your race car
- Design your racetrack
- Conduct a fair test and record results
- Share what you learned
When you’ve earned this badge, you'll have designed a race car and a race track and carried out “fair tests” to learn how design affects speed.
What Does VTK Recommend?
The Volunteer Toolkit breaks earning this badge into two meetings. Like other plans in VTK, word-for-word scripts are provided. However, the activities are listed below:
- Girls rolls different sizes/types of balls back and forth and make observations about the amount of force necessary with each type of ball
- Talk about rolling the balls and the force required. Discuss the concept of friction
- Brownies draw a race car--point out that engineers draw things first, then create models
- Make a car with a variety of craft supplies--either supply wooden wheels or try bottle caps. Leader should build one that the girls can reverse engineer. Talk about how wheels reduce the area of the car that is on the ground, thereby reducing friction. To make the cars go faster, reduce friction.
- Girls share their design with others (end of meeting 1)
- Create simple ramps with poster board, cardboard, books etc. Test the cars on them. Discuss how changing the height of the ramps affects the cars
- Discuss force, friction, incline and gravity
- Discuss "fair test" and then have the girls design a race track--a ramp that more than one car can run on at a time. Work in groups
- Race the cars; record the results and then try to improve the cars.
- Discuss the results
Our Meeting
I have Brownies and Daisies. Last year the Brownies were Daisies and did the Model Car badge and had a great time with it. Only one of my Daisies was with me last year and she either enjoyed this badge or was absent that day. In either case, she'll survive doing this badge again. It was a last minute thing last year so we didn't spend as much time on friction as I would have liked to do, so the Brownies will do friction with the Daisies.
I skipped the exercise with the balls. I want them seated and busy upon arrival and I thought they'd tire of it too quickly. Rather, I had Legos on the table (my daughter had a huge set and I bought some knock-off car kits at the dollar store so we had enough wheels). I told the girls to build a race car. They could make it as big or small as they wanted. I skipped the drawing because of time constraints and because I have some artists who would want to spend a long time on it and some who hate it when I bring out the pencils. Since none of them draw well enough for their drawing to look much like the car, I decided that was an exercise we could skip.
Once everyone had arrived and had time to build a car, we did our opening with the Pledge and Promise. I planned to do the ball exercise but our balls had disappeared, or I didn't dig deeply enough into the toy box. Instead, we talked about friction and rubbed our hands together to feel it. Then we rubbed our hands on the waxed floor, and found it was harder to get them hot because of friction. I told them that without friction, a car I pushed on our end of the room would go until it hit the wall on the other side.
Next, we did the Daisy friction stations. Since I have 16 girls, I sent up four stations. Each was elevated by two books (I have a supply of religion text books that are all the same size). On the floor under the ramp, I had a piece of roll paper with measurements. Each girl ran her car at each station and recorded how far it went. She then changed the car and tried again. My surfaces were: a book (slick cover), a piece of foam carpet padding, a book wrapped in a towel and a plastic yard sign. My data sheet is here.
I told them to watch the other girls' cars so everyone could see which ones went the furthest so they could try to make their second car more like the one that went far. The second cars were all bigger and heavier than the first ones. Surprisingly, the ramp that sent the cars the furthest was the carpet pad.
Next time we'll move on to ramps.
What I Would Do Differently
If I had this to do over again, I would have removed the wheels and axles from the boxes I got at the dollar store and given the girls each a set, plus let them at the Legos. Then, when we are done, I could give each girl "her" box, with the pieces that came with it and send them home, without sorting needed. As it is, they used the wheels and axles from the dollar store set, and some of my pieces and trying to sort them out is going to be a pain. I don't want the dollar store sets, and I don't expect to redo the Brownie badge when my Daisies are Brownies, so I won't need it for that.
Have you done these badges? Tell us about it in the comments.
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