TITLE: Atomic Structure: Rutherford’S Experiment

TITLE: Atomic Structure: Rutherford’s Experiment

PURPOSE: In part I, the purpose of this lab is to determine the size and shape of an object by indirect means. In part II, the purpose of this lab is to determine the configuration of the partition inside the disc.

BACKGROUND INFORMATION: directly. Nevertheless, under the Imagine how little you would be able to leadership of British physicist E. R. accomplish if the room in which you Rutherford, these ingenious worked were so dark that you could not experimenters were able to establish that see the materials you were working with. the atom had a nucleus. Imagine how limited your observations It is not practical to reproduce the would be if the object of your scrutiny classic experiments of Rutherford and were so small that it could not be seen, his group in a high school laboratory. even with a microscope. When you Some idea of the challenge that faced think of how difficult experimentation these researchers can be gained, would be under such adverse conditions, however, by playing the game described you will gain some appreciation for the below. This game simulates the enormous technical problems experiments done by the Rutherford confronting early atomic scientists. team. In playing, you will determine, by These scientists had as their indirect means, the size and shape of an target—the atom—a bit of matter so object that you cannot see or touch. small that there was no hope of seeing it

Also include in your background:  A description (and picture) of Rutherford’s experiment in determining the atom has a nucleus.  Include what Rutherford’s conclusion was after his famous experiment.  Describe Rutherford’s model of an atom.  Include how this lab is similar to Rutherford’s experiment.

PROCEDURE: PART I: 1. When you arrive at the lab station, you will find a sheet of cardboard, plywood or metal resting on top of a hidden object. Do not look under the board! Roll a marble under the board with moderate force. Observe where it comes out. (If the marble does not come out, call the teacher to retrieve it for you, so that the shape of the object under the board will remain a mystery!) Did the marble hit the object? Can you conclude anything about the size or shape of the object from the path of the marble? 2. Working from all four sides, continue to roll the marble under the board, making observations of the rebound path. Your goal is to determine the size and shape of the object by this method. You may want to put a large sheet of construction paper on top of the board so that you can trace the entry and exit paths of the marble. Do not draw directly on the board. 3. When you think you know that size and shape of the object, draw a full-size sketch of it on a piece of paper (i.e in your lab book). Check your results with the teacher. Do not look under the board until the teacher confirms your results. 4. Complete TWO mystery objects in all.

PART II: 1. Record the OB-SCERTAINER number. 2. Carefully shake and tilt your OB-SCERTAINER. 3. From the sound and path of the steel ball, determine the shape and location of the partition or partitions. 4. Draw your best guess in your lab book. 5. Complete for 12 OB-SCERTAINTER disks.

DATA TABLE: PART I: Object #1: for example:

Object #2:

Part II Disk #1 for example:

Disk #2: Disk #3: Disk #4: Etc.

Calculations: N/A

Conclusion: Make sure you include this section. Ask yourself, what new information did I gain through doing this lab. If you can’t think of anything to write, look to your purpose and see if you’ve fulfilled your purpose.

Questions: 1. Until Rutherford’s model of the atom, what was the model of the atom that was most commonly accepted by scientists? Describe this model. 2. In Rutherford’s experiment, identify the following: a. What was shot b. What was the target made of 3. In Rutherford’s experiment, what was the expected result of the particles being shot at the foil? 4. In Rutherford’s experiment, where did most of the particles go? 5. In Rutherford’s experiment, what was the unexpected result? 6. What did Rutherford conclude about the atom that would explain the unexpected result? Explain. 7. Why is Rutherford’s model (with electrons orbiting the nucleus like planets around the sun) not necessarily correct? Explain.