A child looks at a cold glass and writes, “Condensation.” They have named a relevant process. But have they said what they can see, or explained how it happened?
When reviewing Science homework, it helps to separate those two jobs. An observation reports evidence. An explanation connects that evidence to a scientific idea. The distinction gives you something specific to discuss when an answer feels incomplete.
Here is a short practice activity for a child who has already learnt about condensation. The examples and parent prompts are our own practical suggestions, not an official marking guide. Follow the wording of the actual question and your child’s school guidance.
First, decide what the question wants
Before changing an answer, ask your child to point to the task in the question. Does it ask what was observed? Does it ask why something happened? Does it ask for both?
- For an observation: identify what can be seen, measured or read from the information provided. Include the relevant place, change or measurement.
- For an explanation: connect a scientific idea to the particular situation. Naming a topic alone may leave the connection unstated.
This is a practice distinction, not a rule that every question containing “describe” or “explain” must follow an identical sentence pattern. Read the whole question, including its diagram and any instructions.
One glass, two different answers
Invented situation: A clear, unbroken glass contains ice water. Its outside is dry at the start. No water is spilled. After a while, small liquid droplets appear on the outside.
Use these stated conditions for the questions below. The hero image is an illustration, not a record of this activity.
Question A: What change was observed on the outside of the glass?
“Small liquid droplets appeared on the outside of the glass, which was dry at first.”
This answer identifies the change and its location. It stays with the observation instead of supplying a reason that Question A did not request.
Question B: Explain how the droplets formed there.
“Water vapour in the surrounding air lost heat when it came into contact with the cold outer surface of the glass. It condensed into liquid water droplets on that surface.”
The explanation names where the water came from, what changed and where the liquid formed. Condensation is the change from water vapour, a gas, to liquid water; the USGS Water Science School explains this change of state.
A useful follow-up is, “Which words explain the source of the water?” If your child answers “the ice inside”, return to the stated conditions and the distinction between the inside and outside of the glass. In this situation, the outside droplets come from water vapour in the surrounding air.
Repair the missing connection
You do not need to rewrite the entire answer for your child. Pick the part that needs attention and ask one focused question.
| Child’s answer | A useful next prompt |
|---|---|
| “It got wet.” | “Which part became wet, and what appeared there?” |
| “Because of condensation.” | “What substance changed, and what did it change into?” |
| “The water came through the glass.” | “The glass is unbroken and nothing spilled. What source of water does your condensation explanation need?” |
| “Liquid droplets appeared outside because water vapour condensed.” | “Which part reports the observation? Which part gives a reason?” |
Let your child supply the revision. If they cannot explain the concept yet, look back at their lesson notes together before asking them to practise another answer. A longer sentence will not fix a missing idea by itself.
Try a short sentence sort
For each sentence below, decide whether it reports an observation, gives an explanation, or mixes both. Then complete the suggested task. These are invented examples for practice.
- “Small droplets appeared on the outside of the cold glass.”
Classify the sentence. Is it enough to answer a question asking why the droplets formed? - “Water vapour from the surrounding air condensed into liquid on the cold surface.”
Classify the sentence. Identify the source of the water. - “The seedling grew from 4 cm to 7 cm because it received more light.”
Suppose the only information supplied is those two height measurements. Separate what the measurements support from the reason that still needs evidence.
Open the suggested answers
1. Observation. It states what appeared and where. It does not yet explain why.
2. Explanation. It describes a change of state and locates it at the cold surface. The named source is water vapour in the surrounding air.
3. Both an observation and a proposed explanation. The heights support “The seedling grew from 4 cm to 7 cm.” They do not, by themselves, establish that extra light caused the growth. Do not add that cause unless the question supplies evidence to support it.
End with one question your child can use independently
Ask: “Am I reporting what happened, explaining why, or doing both?” Have your child underline the relevant part of their own answer. This makes the review concrete without turning every response into a memorised paragraph.
For questions with tables or measurements, continue with using the numbers in a Science answer. For planning investigations, our fair-test practice focuses on choosing what to change and what to keep the same.
If you are exploring support for your child, see Genie’s Primary Science programmes.
Source note: Checked on 16 October 2026. The USGS source above supports the condensation definition. The Exploratorium’s Process Skills guide distinguishes gathering observations from constructing explanations. Our examples and prompts adapt that distinction for home practice; they do not claim a particular mark allocation or result.