observable

Everyday

1. Observable means able to be seen or noticed. tree →
2. (science) An observable fact is one you can check by looking, measuring or testing. tree →

In the lessons

In science lessons: observable changes in an experiment (colour, bubbles, temperature). In astronomy: the observable universe.

Examples

• The change in colour was easily observable. tree →
• Write down every observable change. tree →
• The observable universe is the part we can see from Earth. tree →
• There was no observable difference between the two plants. tree →
• Melting ice is an observable change of state. tree →
• Bacteria are not observable without a microscope. tree →

Note

From «observe» + «-able»; drop the e. In science, an observation is what you notice; a conclusion is what you work out from it.