Last updated: August 16, 2018
Predict Old Faithful
- Grade Level:
- Upper Elementary: Third Grade through Fifth Grade
Though most geysers are not predictable, Old Faithful is famous for its regularity. Use the rangers' formula below to predict its next eruption. You will need a place to record your work and answers.
Open the Old Faithful Geyser Live-stream Webcam. Wait for Old Faithful to erupt and time its eruption from when water begins splashing continuously out of the cone until only steam is coming out.
A. Start Time: _______
B. End Time: _______
C. Length of Eruption (to nearest 1/2-minute): _______
Using the table below, find the length of the eruption (C) in the first column. Read directly across to the second column in the same row and note the interval or number of minutes (D) until the next eruption.
|C. Length of Eruption||D. Interval Until Next Eruption|
|< 3 minutes||68 minutes|
|> 3 minutes||94 minutes|
Add the start time for the first eruption (A) with the interval number of minutes until the next eruption (D). This is the prediction for the next eruption!
_________(A) + _________(D) = ____________ (Your Prediction!)
Return to the Old Faithful Geyser Live-stream Webcam to find the rangers’ prediction for the next eruption: __________ How close is your prediction to theirs? ________________________
Watch the next Old Faithful Geyser eruption. When did it start? ________ How did the actual start time compare to your prediction? To the rangers’ prediction? Remember, Old Faithful is a natural feature and changes often, so any prediction may not prove to be exactly right.
Worksheet for predicting the next eruption of Old Faithful Geyser.