Using Your Camera's Settings: Program Mode, Shutter Speed, and More

CameraSim should be set to Shutter Priority, which lets you change the shutter speed while the camera automatically adjusts the aperture setting to match. On the Shutter Speed slider, note the current setting (probably 1/125 second) and take the picture. You'll see some blur in the pinwheel, as in this image.

Now try again at 1/20 of a second--the pinwheel should be completely blurred, as in this screen shot. For comparison, slide the shutter speed all the way over to about 1/500 second. The pinwheel is frozen in time.

Experiment With Exposure

If you move the Shutter slider too far (slower than 1/13 second), the aperture reaches its limit (f/36) and can't get any smaller. Shutter speeds below this setting will generate an overexposed photo.

You can also underexpose the photo, but to do that, you'll need to lower the camera's ISO. It's currently set to ISO 200. Lower it to ISO 100, and then notice that once you hit a shutter speed of f/2.8, the aperture is open as wide as it can go--since the camera can't admit additional light, any shutter speed faster than about 1/1250 second generates a dark, underexposed photo.