A cold drink. A growing puddle. Two competing explanations.
Your mission: investigate before you explain. Observe, predict, and compare virtual cups—everything you need is right here in this post.
Open the investigation ↓How can we use observations to evaluate an explanation?
WICOR focus: Inquiry—ask a testable question, compare conditions, and use evidence to revise your thinking.
- I can distinguish observation from inference.
- I can compare cups while changing one intended factor.
- I can support an explanation with specific simulated observations.
Where did the water come from?
A sealed cup contains cold water. Droplets appear on the outside. One student says, “The cup is leaking.” Another says, “The water came from the surrounding air.”
Before choosing an explanation, think of one observation you would want to collect. Keep that question in mind as you investigate.
“The cup must be leaking.”
Change one factor. Compare two cups.
Your testable question: How does the water’s starting temperature affect visible droplets on the outside of otherwise matching cups?
Before clicking Run, make a prediction in your head: Which cup will develop more visible droplets? What result would challenge your prediction?
Ready to observe.
Ready to observe.
Choose different temperatures to compare conditions.
Model rule: Under the fixed room conditions represented here, a cold cup develops visible outside droplets and a room-temperature cup does not. Each run represents a 10-minute observation period shown in a few seconds. The model repeats the same qualitative outcome; these runs are not independent real-world trials. Animation speed and illustrated droplet counts are not measurements.
Watch the pattern develop.
Run at least two comparisons. Try swapping the temperatures between Cup A and Cup B. Does the outcome follow the cup’s label or its temperature?
| Run | Cup A setting | Cup A outside | Cup B setting | Cup B outside |
|---|---|---|---|---|
| Your results will appear here after a run. | ||||
Results remain while this page is open. Record the observations you need in your comment before leaving.
Need help interpreting your results?
Identify which condition developed visible droplets. Compare that with the other condition. Explain what changed and what stayed consistent.
The temperature comparison can show a pattern, but by itself it does not establish where the water came from. Also consider what the model tells you about the cup’s condition and limitations.
Does a leak explain every observation?
The model specifies that both cups are intact and sealed. Would water need to pass through a hole to explain the droplets? What other explanation could fit?
After investigating: reveal the science connection
Air contains water vapor. When a cup’s surface is cold enough relative to the surrounding air’s dew point, water vapor can condense into liquid droplets on the outside. This provides an explanation for outside droplets without requiring a leak.
In real life, results depend on humidity, surface temperature, time, and other conditions. A cold cup will not always develop visible droplets. This model represents one set of room conditions.
Model limitation: The simulation is programmed to illustrate a scientific idea. Its results are not independent proof that the idea is correct.
Read more: U.S. Geological Survey: Condensation and the Water Cycle.
Take your evidence to the comments.
Write one comment below this blog post. Include all four parts:
- My question and prediction: What did you investigate, and what did you expect?
- My evidence: Describe the settings and observations from at least two runs. Include your temperature swap.
- My explanation: What explains the outside droplets? How did your thinking change?
- My next question: What would you investigate next? Name one limitation of this model.
Respond to a classmate: Ask a question about their evidence or suggest a way to strengthen their investigation.
Use the website’s comments section below the post to submit your reflection. The virtual lab does not submit answers for you.
5 Responses
I predicted that the cup with the cold water was going to have water droplets around it. When doing the test, Cup A had the coldest water and made water droplets around it, but Cup B had room temperature water and didn’t make water droplets around it. When I did the second test there was cold water in Cup B and warm water in Cup A. The cup with the cold water still made water drops around it, proving there are in cracks in the cup.
I predicted that you cant see water droplets. In Run I saw that you can see a lot of water droplets, Cup A has more water and water droplets are visible. while Cup B has less water in the cup and no water droplets.. After swapping temperatures, cup B has less water droplets than cup A had. This suggests that people should learn more about water. One limitation is showing why one cup has more water than the other. My next question is why is there limited amount of droplets.
I predicted that it would not be possible to see water droplets. In the experiment, I observed that many water droplets are, in fact, visible: glass A contains more water, and droplets can be seen in it, whereas glass B contains less water and shows no droplets. After swapping the temperatures, glass B shows fewer water droplets than glass A had previously. This suggests that we should learn more about water. One limitation is that it is not explained why one glass contains more water than the other. My next question is: why is the number of droplets limited?
Condensation depends on how cold the cup is relative to the surrounding air and how large the temperature difference is. A colder surface forces more airborne moisture to change from a gas to a liquid o The total amount of water vapor in the surrounding air acts as a hard cap. If the air has low humidity or lacks enough water molecules, fewer droplets will form regardless of how cold the cup is. o Droplets collect on specific microscopic imperfections or nucleation points on the glass rather than spreading out infinitely
I predicted that you cant see water droplets. In Run I saw that you can see a lot of water droplets, Cup A has more water and water droplets are visible. while Cup B has less water in the cup and no water droplets.. After swapping temperatures, cup B has less water droplets than cup A had. This suggests that people should learn more about water. One limitation is showing why one cup has more water than the other. My next question is why is there limited amount of droplets.