This is how sensitive the sensor is inside your camera.
If there is a high ISO the image will appear grainy and will loose some quality. This is because it increases the sensitivity to the sensor inside the camera.
if the ISO is low, the less sensitive the sensor is to light.
After researching we went outside to take our own images, testing different ISO’s to how is changes between each.
This is an example of a low ISO. You can see this because the image is dark. The ISO was set to 100 which meant that the sensor was more sensitive to light.