The Structure of Matter Experiment
Atomic Structure In this experiment, you will have a chance to test the hypothesis that Ernest Rutherford used when determining the size of the nucleus. In his “gold foil experiment,” Rutherford shot alpha particles at gold atoms. Once he realized that the alpha particles were hitting a concentrated positive mass, he developed the nuclear model of the atom. Next, he set out to determine the relative size of the nucleus compared to the rest of the atom.
He reasoned that the smaller the nucleus, the less likely it was to be hit by an alpha particle. This led to a simple comparative ratio: It took a great number of shots to actually hit the nucleus because the size of the atom was so much larger than the nucleus. Rutherford proposed that the “hit ratio” was approximately equal to the volume ratio. This is the hypothesis you will test in this experiment. Objectives §Investigate a scientific hypothesis. Present your findings in a scientific report. Materials
- large box (at least 40 to 50 cm along all sides)
- small block of wood (around 6 to 8 cm along all sides)
- 100 marbles or pellets (airsoft pellets work well)
- ruler
Directions Note: You will need to find a partner to help you perform this experiment.
- Place the box on the floor. The top of the box should be completely open.
- One partner (A) should stand near and facing the box with his or her eyes closed.
- The other partner (B) should place the block somewhere in the box.
- Partner A, with eyes still closed, should then begin dropping marbles into the box, trying to hit the block.
Partner B keeps track of the “hits. ”
- If a marble does not fall inside the box, Partner B retrieves the marble and returns it to Partner A for a re-shot. (A total of 100 marbles should fall inside the box. )
- If the block is hit, Partner B moves it before Partner A resumes his attempts to hit it.
Atomic Structure Student Name: Date Experiment done: Date Report Completed: Name of Grader: Hypothesis: I think more marbles will not hit the block and less marbles will hit the block. Procedure: I took a bag of 100 marbles, a box, and a small block that I put into the box.
My classmate, JaTyse, took the marbles and threw them in one by one while I counted how many hit the block and my other classmate, Derrick, moved the block around as needed. Data: List all observations and measurements including proper labels. I multiplied the length, the width, and the height to get the volume of the block and the box.
For the block I got 2. 5 and for the box I got 3548. 25. I got the volume of the block is 3 percent of the volume of the box. The block was hit 2 times out of 100 so I made that a fraction then I reduced that to get 1/50. I got the block was hit 2 percent of the time.
Conclusion
There were more misses than hits. Out of 100 attempts, there were only 2 hits. Our outcome could be changed by adjusting the distance from the box and the size of the block. Ernest Ruherford’s hypothesis was number of hits over the number of shots equals the size of the nucleus over the size of the atom. His hypothesis is reasonable.
