TEAM BOB

Event Year: 2025
Event Location: Orange County STEM Saturday
Competition: Junior Solar Sprint
Division: 4-6 (JSS Green)
School: Bay Meadows Elementary
Team Name: Bob
Project Name: monkey
Team Size: 4

Event Year: 2025

School: Bay Meadows Elementary

Event location : Apopka high

Competition: Junior solar sprint

Division: 4-6

Team Name: Team Bob

Vehicle Name: Monkey Car

Team Members: William E. (4th grade), Finn B. (4th grade), Athanasya T. (4th grade), Seraphina T. (4th grade)

Meeting Notes:

Meeting 1 10/29/25 2:30-3:30
Team Members Present: William E., Finn B., Athanasya T., Seraphina T.
Tasks to Determine:

Material? – 3d print, Legos, plastic, wood

Power? – Front or Back Wheels

Where to put Eyelet?

How to attach everything? – Hot glue

Wheels and axle? – How to attach to motor

Size and Shape of Body

Size of chassis – Min: 10cm x 27cm (solar panel size) Max: 30cm x 60cm x 30cm

How to hold ping pong ball? – 3d printed bowl, playdough, cup

Meeting 2 11/19/25 2:15-5:00
Team Members Present: William E., Finn B., Athanasya T., Seraphina T.
Task:

Build and Preliminary Test

Determine Gear Ratio to use

Where to glue everything

How to hold ping pong ball

Notes:

Based on the designs sketched by the team during their last meeting, the team constructed their solar car. Gear size ratios were discussed and the team felt that the gear option that provided a mix of both stability and speed was the one they were going to use (10-toothed gear on the motor and 20-toothed gear on the axle).

Initial testing of the car only included verifying whether the motor and gears were operational, using only battery power. The solar panel had not yet been included at this point. Refer to “Solar Car Test 1.mp4”. Testing revealed that there was gear slippage, so gear placement was key in ensuring that the car was operational. This prompted the team to more carefully align the gears when affixing the motor to the car and to add more adhesive to prevent movement.

The team continued to build, adding the solar panel and affixing the ping pong ball holder (to hold the ball) below the solar panel. At this point, the team initiated another round of testing, this time using the solar panel as its source of power. During this round of testing, it was noted that although the wheels rotated quickly when the car was above the ground, when the car was placed on the ground, the wheels did not move or required a push to get the car moving. The lack of rotation suggested that there was not enough power to move the weight of the car. Refer to “Solar Car Test 2.mp4”. This prompted the team to re-evaluate the gear ratio strategy. They concluded that a gear ratio that provided more power, but less speed, may be more beneficial. At this point, the team opted to use the 10-toothed gear on the motor and the 30-toothed gear on the axle.

With the update to the gear ratio, the team conducted a third round of tests, which proved to be more successful. Refer to “Solar Car Test 3.mp4”. One item noted during this testing is that the angle of the solar panel did affect its efficacy in that when it was more flat/horizontal, it did not generate as much power/speed (if any), however when the panel was more vertical, it produced more power. The team concluded that the angle placement on the car was adequate, taking into account that the timing of the test was near dusk when the sun was low.

The team concluded its testing and meeting at 5:00 PM. A final meeting is scheduled for 20 Nov 2025, when final updates and testing will be performed on the car.

Design Drawings:

Finished Specifications

Car Size: L: 28 cm W: 13 cm H: 15 cm	Wheel Size: Front: 4cm x 0.5cm Rear: 4.5cm x 1.5cm
Car Weight: 258 g (no batteries)	Gear Ratio: 30:10 or 3:1

Components and Cost

Material	Cost	New/Recycled
Balsa Wood, motor, gears, wheels, axles, solar panel	None (provided in kit)	New
Rubber Bands	$2.13	New
Hot Glue	$0.44	New
Plastic Cup	$0.08	New
Ping Pong Ball	$0.25	New
Batteries	$1.00	New
Paper Clips	$0.02	New
Alligator Clips	$1.16	New
Googly Eyes	$0.02	New

Test Results

Test Information	Test 1	Test 2	Test 3	Test 4	Test 5
Solar or Battery	Solar	Battery	Battery	Solar	Solar
Weather	Low Sun	Shady	Shady	Low Sun	Low Sun
Date and Time of Day	11/19 4:00	11/20 3:45	11/20 3:45	11/20 3:45	11/20 3:45
Distance Traveled	0 cm	760 cm	760 cm	15 cm	24 cm
Time Elapsed	10 s	4.01 s	3.53 s	2.16 s	3.33 s
Speed (Distance/ Time)	0	189.5 cm/s	215.3 cm/s	6.9 cm/s	7.2 cm/s
Performance Comments	As soon as the vehicle was placed on the ground, the wheels stopped spinning.	Went well but back eyelet fell off and string was close to gear.	Went very well	Was really slow when placed down. Sun was low in sky and string not in line with Sun.	Was still slow.
Improvement Ideas	Change the gear on the axle to help with more power and not as much speed.	Attach back eyelet back to car	None	Bigger angle for solar panel, align string with sun.	Bigger angle for solar panel.