Experiments

An experiment is a test designed to answer a question or check if a hypothesis is correct. Scientists plan their experiments carefully to make sure the results are fair and accurate. Good experiments change only one thing at a time so scientists can see what caused the result. Experiments are at the heart of how science works.

Parts of an Experiment

Every good experiment has key parts. The variable is the one thing you change. The control is the part of the experiment where nothing changes, used for comparison. Constants are all the things you keep the same. For example, if testing which soil helps plants grow best, the type of soil is the variable. The amount of water and light are constants.

Recording and Repeating

Scientists carefully record everything that happens during an experiment. They write down measurements, observations, and results. They also repeat their experiments multiple times to make sure the results are reliable. If other scientists can repeat the experiment and get the same results, the findings are considered more trustworthy.

Fun Facts

• Some experiments in space on the ISS cannot be done on Earth because gravity gets in the way.
• The longest running experiment is a pitch drop experiment in Australia that has been going since 1927.
• Thomas Edison tested over 3,000 designs before finding the right material for his light bulb filament.

Did You Know?

Some of the most important experiments in history were very simple. Isaac Newton used a glass prism to split white light into a rainbow. Alexander Fleming discovered penicillin when he noticed mold killing bacteria on a petri dish he had accidentally left out. Great discoveries can come from simple observations!