It is difficult to conceive of the distances between celestial objects. The Earth and the sun are usually around 149,000,000 kilometers apart and the distance between the sun and other stars are so great that we measure them in units of time called light years. A light year is equal to the distance light can travel in a year, which comes to 9,460,520,400,000 kilometers! All those zeros can make trying to think about how far away things are impossible. But the distances between atomic structures are also very hard to understand. Though an atom is very small, it is made up of mostly empty space. Just like the planets in the solar system, the electrons in an atom orbit at great distance, relative to their size, from the atom’s nucleus.
Are the distances in the solar system proportional to the distances in an atomic system?
- Tennis ball
- Meter stick
- A number of willing participants
- Begin by determining your scale. Making the sun the size of a tennis ball works well.
- On a chart such as the one below, find out the actual radius of the sun and planets and fill them in.
- If you are using a tennis ball to represent the sun, write the scale size of the tennis ball, which is 3.3 cm.
- Calculate the scale size of the planets in the solar system. This can be done by plugging in the actual size of the radius into this simple equation (radius of the planet)(3.3)/(radius of the sun). For example, (radius of Mercury)(3.3)/(radius of sun). (2440)(3.3)/(696000)=8052/696000=.01cm=1mm.
- Fill in the chart.
- Calculate the distances for the scale model of the solar system. Use the same equation, plugging in the actual orbit distance instead of the planetary radius.
- Make a model of the solar system with your friends.
- Go to a very large open space. A public park works well.
- Have one of your friends stand on one end of the large open space holding the tennis ball. You will construct a model of the solar system that assumes the sun to be the size of a tennis ball.
- If the sun is the size of a tennis ball, the planet Mercury is 1mm in diameter and 2.8 meters away. Have one of your friends break off a piece of clay that is 1mm across and stand 2.8 meters from the sun.
- Using your chart, recreate the solar system.
Record a few observations about your model.
- Find out the sizes and distances in an atom. Oxygen is a good atom to start with.
- Have the tennis ball represent the nucleus of the atom.
- Calculate the sizes and distances in the atomic system on another chart using a nucleus size of 3.3cm. You can use the equation (variable size)(3.3)/(size of nucleus).
- Measure out the distance between the nucleus and the first and second electron orbitals, using friends to help you.
- Record a few observations about your model.