Bike Ride

Target Age Group
Middle School

Ojbective
Students will understand the immense distances between the Sun and planets by calculating speed of light at the scale where Earth is the size of a basketball and the Moon is a tennis ball. (See the Solar System in Your Neighborhood activity)

You will need
Paper, pencil, bicycle optional

What to do
1. Nothing travels faster than the speed of light. It is so fast, we cannot see it, but our solar system is so huge – that when we think about communicating in space, we have to factor in the time it takes for light to travel. To find out just how huge the solar system is, let’s bring it down to size a little bit.

2. You can translate the speed of light to the scale where Earth is the size of a basketball. What we know: It takes light (or radio waves) about 8 minutes to go from the Earth to the Sun. In our model the Sun-Earth distance is 1.8 miles.

3. So, to perform the calculation…

1.8 miles divided by 8 minutes = 0.225 miles per minute

0.225 miles per minute times 60 minutes per hour = 13.5 miles per hour

4. Can you ride a bicycle at this rate of speed?

What's Going On?
The speed of light = 186, 000 miles per second. We can’t see light travel, but we can experience it. If you have been talking on the phone and noticed the pauses between when you say something and the other person hears it, that may be because of the delay as the signal gets passed back from a satellite in Space. We also experienced the delay when the astronauts talked to us from the Moon.

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