Leena uses these fruits to make fruit salad for guests. Mango, Kiwi, Apple, Banana, Cherry, Kiwi, Kiwi, Mango, Orange. Calculate the following (a) Proportion of Kiwi (b) Proportion of Mango *
with calculations
Answers
Answer:
If your mailing tube has a cap, use the pencil and ruler to mark a rectangle that is 1 inch (2.5 cm) long and 1/8 inch (3 mm) wide. Use your utility knife to cut out a slit the size of the rectangle. Replace the cap on the end of the tube.
Alternatively, tape two small pieces of black paper to one end of the tube so that there is a 1/8 inch (3 mm) slit between them.
To Do and Notice
Close one eye. Cup your hand around the tube to make a cushion between the tube and your eye and prevent light from leaking in. Put your open eye to the open end of the tube. Hold the tube so that the slit is vertical.
When the slit is stationary, you can’t see much. Keep your head and body still and sweep the far end of the tube back and forth slowly while you look through it. (Make sure the area around you is clear.) Increase the scanning speed and compare the views. Notice that when you sweep the tube quickly from side to side, you can see a remarkably clear view of your surroundings.
What's Going On?
Your eye and brain retain a visual impression for about 1/30 of a second. (The exact time depends on the brightness of the image.) This ability to retain an image is known as persistence of vision.
As you swing the tube from side to side, the eye is presented with a succession of narrow, slit-shaped images. When you move the tube fast enough, your brain retains the images long enough to build up a complete image of your surroundings.
Different technologies take advantage of human persistence of vision. For example, when we watch a movie, it feels like a continuous experience even though the screen is dark about half the time. Films show one new frame every 1/24 of a second. Depending on the film, each frame is shown twice or three times during this period. The eye retains the image of each frame long enough to give us the illusion of smooth motion. Even newer TV and computer monitors take advantage of our failure to notice the constant and steady refreshing of images right in front of us.