what is a constant variable in science

A constant variable in science is something you keep the same during an experiment so it does not affect the results.

Quick Scoop

If you change only one thing in an experiment, it is easier to see what caused the outcome. That is why constants are important: they help make the test fair and the results reliable.

Simple example

If you are testing how light affects plant growth, you might keep these constant:

• the type of plant,
• the amount of water,
• the soil,
• the pot size.

One small note

Some sources use “constant variable” to mean a controlled variable , which is something held steady in an experiment. In broader science, a constant can also mean a value that does not change, like the speed of light.

If you want, I can also give you a 1-sentence definition for homework.