Half-life GIZMO COMPLETE

SCIENCE 4024Half-life GIZMO COMPLETE SCIENCE 4024Half-life GIZMO COMPLETE Name: Meher Ghai Date: 3/23 Student Exploration: Half-life Vocabulary: daughter atom, decay, Geiger counter, half-life, isotope, neutron, radiation, radioactive, radiometric dating Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. Have you ever made microwave popcorn? If so, what do you hear while the popcorn is in the microwave? The sound of the kernels popping. 2. If you turn the microwave on for two minutes, is the rate of popping always the same, or does it change? Explain. It changes. It starts with no popping. Then fast popping. And lastly slow popping. Gizmo Warm-up Like an unpopped kernel in the microwave, a radioactive atom can change at any time. Radioactive atoms change by emitting radiation in the form of tiny particles and/or energy. This process, called decay, causes the radioactive atom to change into a stable daughter atom. The Half-life Gizmo allows you to observe and measure the decay of a radioactive substance. Be sure the sound SCIENCE 4024Half-life GIZMO COMPLETE is turned on and click Play ( ). 1. What do you see and hear? I saw the radioactive atoms quickly then slowly turn into daughter atoms. I heard electric zappy noises. Note: The clicking sound you hear comes from a Geiger counter, an instrument that detects the particles and energy emitted by decaying radioactive atoms. 2. What remains at the end of the decay process? Daughter Atoms 3. Is the rate of decay fastest at the beginning, middle, or end of the process? Beginning SCIENCE 4024Half-life GIZMO COMPLETE Get the Gizmo ready: Activity A: • Click Reset ( ). Be sure that User chooses half- Decay curves life and Random decay are selected. • Check that the Half-life is 20 seconds and the Number of atoms is 128. Question: How do we measure the rate of radioactive decay? 1. Observe: Select the BAR CHART on the right side of the Gizmo and click Play. A. What happens to the numbers of radioactive and daughter atoms as the simulation proceeds? The amount of daughter atoms increases, and radioactive atoms decrease. B. Do the numbers of radioactive and daughter atoms change at the same rate throughout the simulation? Explain. No. It is at it’s fastest at the beginning of the simulation. 2. Experiment: Click Reset, and select the GRAPH tab. Run a simulation with the Half-life set to 5 seconds and another simulation with the Half-life set to 35 seconds. 3. Interpret: How does the Half-life setting affect how quickly the simulated substance decays? The time it would take for radioactive atoms to turn to daughter atoms would decrease if the half-life were shorter. (Activity A continued on next page)