Half Life Gizmo Answer Key Activity B ^new^

If the Gizmo states the half-life of Uranium-235 is 700 million years (approximate standard used in many textbooks), and we have 2 half-lives:

Explanation: Look for the time when the number of radioactive atoms drops by half. At time 0 → 200 atoms. At time 10 minutes → 100 atoms (half). That interval (10 minutes) is the half-life. half life gizmo answer key activity b

In the Gizmo, you are typically working with a fictional isotope, but the math applies to real elements like Uranium-238 or Carbon-14. If the Gizmo states the half-life of Uranium-235

| Time (seconds) | Number of Radioactive Atoms (Starting: 100) | |----------------|----------------------------------------------| | 0 | 100 | | 5 | 50 | | 10 | 25 | | 15 | 12 or 13 | | 20 | 6 or 7 | | 25 | 3 | | 30 | 1 or 2 | That interval (10 minutes) is the half-life

The Gizmo includes random decay. After 5 half-lives, you expect 3.125 atoms, but you might see 2, 3, or 4. The simulation says "Approximately," so your answer should be approximate.

In our example above (25% remaining), the sample has gone through exactly .

Activity B of the Half-life Gizmo, "Measuring half-life," focuses on identifying the specific half-life of different isotopes using the simulation's graphing tools. Below are the key answers and steps for this activity:

If the Gizmo states the half-life of Uranium-235 is 700 million years (approximate standard used in many textbooks), and we have 2 half-lives:

Explanation: Look for the time when the number of radioactive atoms drops by half. At time 0 → 200 atoms. At time 10 minutes → 100 atoms (half). That interval (10 minutes) is the half-life.

In the Gizmo, you are typically working with a fictional isotope, but the math applies to real elements like Uranium-238 or Carbon-14.

| Time (seconds) | Number of Radioactive Atoms (Starting: 100) | |----------------|----------------------------------------------| | 0 | 100 | | 5 | 50 | | 10 | 25 | | 15 | 12 or 13 | | 20 | 6 or 7 | | 25 | 3 | | 30 | 1 or 2 |

The Gizmo includes random decay. After 5 half-lives, you expect 3.125 atoms, but you might see 2, 3, or 4. The simulation says "Approximately," so your answer should be approximate.

In our example above (25% remaining), the sample has gone through exactly .

Activity B of the Half-life Gizmo, "Measuring half-life," focuses on identifying the specific half-life of different isotopes using the simulation's graphing tools. Below are the key answers and steps for this activity: