Half-life Gizmo-REVISED ANSWERS-ALL CORRECT.Name: Katheryn Castillo Class: Period 4 2022
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 ...
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? I can hear the kernels of the popcorn popping
2. If you turn the microwave on for two minutes, is the rate of popping always the same, or
does it change? Explain. I think the rate of the popping stays the same, if you put 2 minutes
on a microwave and start it I think the bag of popcorn can all be popped and ready to eat in
2 minutes
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
is turned on and click Play ( ).
1. What do you see and hear? I heard some sort of popping noise and I saw all of the
radioactive atoms turn into Daughter atoms
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? Everything that once was Radioactive
atoms are now Daughter atoms
3. Is the rate of decay fastest at the beginning, middle, or end of the process? The rate of
decay is fastest at the beginning of the process
, Get the Gizmo ready:
Activity A: • Click Reset ( ). Be sure that User chooses half-
life and Random decay are selected.
Decay curves • 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 number radioactive atoms goes down as they turn into daughter
atoms and in turn the number of daughter atoms goes up.
B. Do the numbers of radioactive and daughter atoms change at the same rate
throughout the simulation? Explain. Yes, every time a radioactive pops per say it
turns into daughter
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. Sketch each
resulting decay curve graph in the spaces below.
Half-life = 5 seconds Half-life = 35 seconds
3. Interpret: How does the Half-life setting affect how quickly the simulated substance decays?
The less time there is for the Half-life the faster the radioactive atoms turn into daughter atoms.
(Activity A continued on next page)
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