Different light sources emit different amounts of radiant energy, but this isn’t always easy to see. Make this visible by creating a solar weight-lifter! This activity converts light energy into mechanical energy in order to lift weight, showing a concrete measurable difference between the light sources. Which light source can lift the most weight?
More in-depth instruction can be found in a free educational guide here.
Step 1: Materials
- high torque motor (2mm driveshaft)
- different light sources (incandescent, fluorescent, LED, sun)
- 3V solar panel*
- cup (with two holes drilled around the top, so string can be threaded through)
- screw hub*
- weight (washers)
- duct tape
*these parts can be found (the panel is $12 and the screw hubs are 5 for $5) at the REcharge Labs online store, but another solar panel or a DIY screw hub is also an option!
Step 2: Make the Weight-lifting Device
Tie the string onto the cup and tie the other end onto the screw hub, leaving about a foot of length in between.
Step 3: Add the Solar Panel
Attach the screw hub to the motor. Connect the 3V solar panel to the motor.
Step 4: Attach to a Table
Securely attach the motor to a table with duct tape, allowing the string to hang freely off the side.
Step 5: Test How Much Weight Your Solar-lifter Can Lift
At the first light source, place the solar panel directly facing the light, positioning it 1 cm from the light source. (If using the sun as the light source, distance will not be a factor.) Measure how much weight can be put into the cup, while still allowing the string to lift the cup all the way up to the motor.