Abstract

Objective

The objective of this electronics science fair project is to determine how varying the amount of light falling on the Frightened Grasshopper Solar-Powered Bug affects its level of movement.

Introduction

In this electronics science fair project, you will build and test your own life-size robot grasshopper! The "Frightened Grasshopper" toy is an educational kit for the first-time electronics experimenter. It demonstrates how energy can be turned into different forms. First, radiant energy, which comes from the Sun or from a lightbulb, is turned into electrical energy by a small solar panel. A solar panel (solar means of or relating to the Sun) is a panel that produces either electricity or heat when light shines on it. Check out Kid's Info: Answers to Questions Frequently Asked by Kids! in the Bibliography, below, to learn more about turning solar energy into electrical energy. The electrical energy from the solar panel is then used to make a small motor spin. In other words, the electrical energy is converted into kinetic energy. Kinetic energy is defined as the energy of motion. The motor has a small weight on it, which is unbalanced, so when the motor is turned on, the unbalanced weight moves, making the grasshopper wiggle and move in circles. Lots of things around your house have motors in them, including your refrigerator, DVD player, hairdryer, and computer printer, to name a few.

In this electronics science fair project, you will vary the amount of light that hits the solar panel on the grasshopper and observe how this affects its activity. To do this, you will hold the grasshopper in your hand and bring it close to a lightbulb. You will measure how close the grasshopper has to be before the motor starts to spin. The goal is to measure how the bulb's wattage (which is the amount of power; higher wattage means more light and more radiant energy) affects the distance at which the grasshopper is activated.

Terms, Concepts, and Questions to Start Background Research

• Energy
• Radiant energy
• Electrical energy
• Solar panel
• Kinetic energy
• Wattage
• Average, as in math

Questions

• What are the different parts of the "Frightened Grasshopper" toy?
• What is the area, in square centimeters, of the solar panel on the grasshopper?
• What is the definition of kinetic energy?
• What part of the toy converts electrical energy into kinetic energy?

Bibliography

• Energy Information Administration. (2008). Forms of energy. Retrieved May 20, 2009, from http://www.eia.doe.gov/kids/energyfacts/science/formsofenergy.html
• Solar Energy International. (n.d.). Kid's Info: Answers to Questions Frequently Asked by Kids! Retrieved August 26, 2009, from http://www.solarenergy.org/resources/youngkids.html
• The Tech Museum of Innovation. (2005). Universal Robots: The History and Workings of Robots. Retrieved August 29, 2009, from http://www.thetech.org/robotics/universal/index.html
• Pacific Gas and Electric Company. (2002). Electriciy Generation and Distribution. Retrieved August 26, 2009, from http://www.pge.com/microsite/pge_dgz/more/electricity_gen.html
• How Stuff Works. (2009). How Robots Work. Retrieved May 20, 2009, from http://science.howstuffworks.com/robot1.htm
• Rathjen, D. (2001). Watt's a Joule? Retrieved May 22, 2009, from http://www.exploratorium.edu/theworld/energy/joules.html

For help creating graphs, try this website:

• National Center for Education Statistics. (n.d.). Create a Graph. Retrieved May 20, 2009, from http://nces.ed.gov/nceskids/CreateAGraph/default.aspx

Materials and Equipment

• The Frightened Grasshopper Solar-powered Bug is available from online sellers, such as www.amazon.com
• Lamp
• Incandescent lightbulbs; 25, 60, 100, and 150 watts (W) (1 of each)
• Lab notebook
• Ruler, metric
• Cloth tape measure, metric
• Helper
• Graph paper

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Experimental Procedure

Preparing for Testing

1. Assemble the Frightened Grasshopper using the instructions that came with the toy.
   1. Because the toy is fragile and has some small parts, the assembly should be done with the help of an adult.

Figure 1. Parts for the Frightened Grasshopper robot kit.

2. Make sure the grasshopper works by taking it outside and exposing it to bright sunlight. It should start to move when in the sunlight. See the video, below.

Video of frightened grasshopper in the sun.

Performing the Experiment.

1. Unplug the lamp.
2. Put a 150-W incandescent lightbulb in the lamp.
3. Plug it back in.
4. Turn the lamp on.
5. Remove any sources of light, other than the lamp you are using.
   1. Turn off any other lamps in the area and block sunlight from entering the room.
   2. The room does not need to be very dark or pitch black. Just make sure there are no bright sources of light, other than the lamp.
6. Hold the grasshopper near the lightbulb, with the solar panel facing the lightbulb. The grasshopper should not be quivering yet.
   1. Try to keep the solar panel pointing directly at the lightbulb so that you get consistent results.
   2. Depending on the shape of your lamp, you may need to remove the lampshade to get close to the lightbulb. Use your judgment.
7. Have your helper measure the distance at which you're holding the grasshopper away from the lightbulb with the ruler and record the number (in centimeters, cm) in a data table, like the one below, in your lab notebook.
   1. Use the ruler to measure the distance. If the ruler is too short, use the cloth tape measure.

Trial 1 Data Table

8. Move the grasshopper closer to the lightbulb, until it starts to quiver.
9. Have your helper record the distance, in centimeters, at which the grasshopper started to vibrate, in your data table.
10. Repeat steps 5–6 two more times to ensure your results are accurate and repeatable. Try to use the same starting position each time.
11. Turn the lamp off and unplug it.
12. Repeat steps 1–11 with the other three lightbulbs. You should have a total of three trials for each lightbulb.
13. Repeat steps 1–12 two more times, so you have three data tables.

Analyze Your Data

1. Calculate the average distance, as follows. Add the three trials within each data table for each lightbulb, and then divide by 3. Record the averages in your data tables.
2. Make a graph for each of your three test sets, either on paper, or using a website like Create a Graph.
   1. Put the wattage (25, 60, 100, and 150 W) on the x-axis.
   2. Put the average distance, in centimeters, on the y-axis.
3. How did the wattage affect the grasshopper's movement? Think about what you could do to improve the procedure.

Variations

• Try other kinds of lightbulbs, such as energy-saving fluorescent bulbs. Graph wattage vs. distance, as in the main procedure.
• Experiment with different kinds of colored plastic to see which block light from activating the grasshopper. This might be easier using filters over a flashlight.
• Take the grasshopper outside at 9:00 AM on a sunny day and place it on a flat surface in the sunlight. Record the number of times it spins around in 1 minute. Repeat this test every hour until it is no longer is activated by the sunlight. Graph the time of day on the x-axis and the number of rotations on the y-axis.
• Devise a way to make a sun-activated alarm clock from the grasshopper.

• For more science project ideas in this area of science, see Electricity & Electronics Project Ideas.

Credits

David B. Whyte, PhD, Science Buddies

Last edit date: 2009-08-02 09:38:00