Have you ever walked from a dim corridor into bright sunlight and felt your eyes take a moment to settle? Or blinked when something came near your face even though you did not mean to?

Today we will look carefully at how the eye reacts to light and to a sudden sound nearby, and we will find out which of those reactions we choose and which the body does on its own.

What do you think the dark circle does when bright light hits it?

Later we will also watch a blink. Some body actions happen quickly without us deciding. We will find out more when we test that together.

First we will watch a partner's pupil in bright light. Then your partner will close their eyes and cover them with cupped hands for 30 seconds, and we will watch the pupil the moment the eyes open.

Talk with your partner: what do you think the pupil will look like in bright light? What will it look like the moment the eyes open, and what will it do next?

Now look at this clear plastic sheet. Later we will hold one between partners like a little window and make one gentle clap beside it. Will a person blink at that gentle clap, even if they try not to?

Work in pairs. The bright zones are by the windows or under the bright lights. If you are waiting for a turn there, stand a step back from a nearby pair, watch the same eye when they invite you, and jot what you notice.

One person is the watcher and one is the partner. First the watcher looks carefully at the partner's pupil in the brighter light and jots whether it looks bigger or smaller.

Then the partner closes both eyes and covers them with cupped hands, resting lightly and never pressing, for 30 seconds, still facing the light. Watcher, look at your partner's eye before the hands come away. The moment the eyes open, is the pupil bigger or smaller than before? What does it do in the next few seconds? Jot both on your Investigation Journal page, then swap roles.