Search for Science Fair Projects

1000 Science Fair Projects with Complete Instructions

Spectrophotometry

Spectrophotometry is measuring how much light a liquid absorbs to find out what is in it.

Think of it this way

When you shine a flashlight through a glass of clean water, the light passes through easily. When you add food coloring, the water blocks more light. Darker color means more light is absorbed. A sensor on the far side of the glass measures how much light gets through.

Explaining spectrophotometry by grade level

Some liquids have color, and some do not. When oil-eating bacteria clean up oily water, the water gets clearer over time. You can shine a light through the water to see the change. Darker water blocks more light, and clearer water lets more light pass through.

Projects that explore spectrophotometry

Oil-Eating Bacteria in a Test Tube

Spectrophotometry measures how much light a liquid absorbs, revealing what is dissolved or suspended in it. In this experiment, you track the optical density of carbon-deficient growth media as Acinetobacter calcoaceticus RAG-1 bacteria multiply and consume oil. As the bacteria grow, the media grows cloudier and absorbs more light. That means each 24-hour reading directly quantifies bacterial growth linked to oil breakdown.

Hard