Solar School Activity Sheet

 

Solar Powered Cars

 

Introduction

One of the ways that we can reduce the amount of pollution from traffic is to power our vehicles from renewable resources. To demonstrate this, the World Solar Challenge Car Race from Darwin to Adelaide each year involves dozens of cars that are powered only by the energy of the sun.

 

In this activity, you will design and build your own solar cars and race them just like in Australia's World Solar Challenge!

Background
Solar power comes from the energy of our Sun, a yellow dwarf star located 150 million kilometres from the Earth. It is a middle-aged, mid-size star compared to the billions of other stars in the universe.

 

The interior of the Sun is a region very high in temperature and filled with dense gases. The Sun's core is estimated to be approximately 27 million degrees Fahrenheit. Heat and light from the Sun are produced through a process called nuclear fusion.

 

Sunlight is an excellent energy source and the future of using solar power is very exciting. The Sun's energy can be used to heat and cool buildings, generate electricity, operate communication and navigation systems and even power solar cars, like the ones in the World Solar Challenge.

 

Solar-powered cars all get their fuel from the same place - the Sun. The cars use hundreds of photovoltaic cells to convert sunlight into electricity. Each cell produces about 0.5 volts of electricity.

 

When the World Solar Challenge teams design their electrical systems they have to allow for variations in sunlight. The Sun's energy powers the car's motor and charges a battery for use when the Sun is hidden by a cloud. If a car is designed to put all of its energy toward driving and keeps nothing in reserve, it will stop completely in cloudy weather. If too much energy is diverted to the battery, the engine runs too slowly to keep up in the race.

 

Engineers and scientists still have many questions and problems to tackle before solar power becomes an efficient and economical way to fuel vehicles. But as the demand on fossil fuel resources increases, research will continue to search for alternative energy sources, including harnessing the Sun's energy to drive a vehicle. The most exciting part of using solar power as an energy source is that it is pollution free and inexhaustible. If research continues, one day solar energy may replace today's combustion engine cars!

 

Vocabulary

Solar--Referring to the Sun.

Solar Collector--An object that gathers the Sun's energy.

Nuclear Fusion--The process by which the Sun produces heat and light.

Fossil Fuels--Coal, oil and natural gas. Substances that have been formed by the decay of the remains of ancient plants and animals - in a sense they are a form of "buried sunshine."

Solar Panel--A device that captures the Sun's energy so it can be used for heating and other purposes.

 

Introductory Activities

Investigate other uses of solar power.

  1. Discover how light and heat can be used as energy. Try filling one pie pan half full with white sand and another half full with dark soil. Insert a thermometer in each pan with the bulb just below the surface. Record the temperatures for both pans. Place pans at an equal distance under a lamp with a 150-watt light bulb. Turn the light on and wait for five minutes.

    2.  

    Questions

    Test the temperature in both pans and record your findings. Are the pans the same temperature? What would happen if the pans were further away from the light? How could scientists use this energy?

  2. A radiometer is an instrument that measures radiant energy. See if your school has one you can use to study how light in your classroom varies from place to place.

    3.  

    Questions

    What happens if it is put in front of a light source? If you block the light with your hand, what happens? What kind of energy do the moving vanes have? Why are the vanes black and white? What powers the radiometer?

     

  3. Colour can change the amount of light and heat that are absorbed. Find out which colours are the most receptive. Paint a few tin cans different colours. Make sure you use matt paints or ones that aren't too shiny. Fill each can with equal amounts of water. Using a thermometer, record the temperature in each can. Allow them to sit in the sun for a few minutes. Test the temperatures in the cans and then arrange them in a rainbow from coolest to hottest.

    4. Questions

    Now that you know which colours are coolest, what colours will you wear in the summer from now on? What about the winter? What colour would you pick to paint your house to save energy?

     

  4. Contact your local utility company and ask them about solar heating and cooling systems. Compare the costs of using solar power to natural gas and electricity. Prepare an annual budget and see which energy source is the most economical.

 

Main Activity

Build a custom-designed vehicle propelled by photovoltaic cells.

 

Materials:

 

  1. Place the solar cells side by side.
  2. Connect them in a series by twisting the negative and the positive wire of one cell to the next cell.
  3. Attach the motor to the remaining positive and negative wires.
  4. Attach the propeller to the motor. Observe how fast it turns.
  5. Design a custom body for the car. Compare your's with your classmates'.
  6. Try a few time trials to see whoÕs car is fastest. How can you modify your car to make it go faster?

 

Questions

1. What would happen if you used more cells? Does placement of the cells affect the power of the motor?

2. Does the arrangement of the cells affect the design of your car? How could you arrange the cells to make the car more efficient?

3. Do you have any solar-powered items at home? Where else could solar cells be used at home? At school?

 

Extension