Passage
Read the full passage. Bracketed letters like [A] mark the four positions for the insert-text question.
Why Gloves Don't Work on Every Touchscreen
¶1 Tapping a smartphone screen with a bare finger works instantly, but the same tap through a glove often does nothing. The screen has not become less sensitive. It is simply built to sense touch in one particular way, and a glove does not match that way. Touchscreens fall into two main types, based on what they actually detect. One type senses pressure. The other senses electricity. Engineers call the first type a resistive touchscreen and the second a capacitive touchscreen.
¶2 A resistive touchscreen is built from two thin, flexible layers with a tiny gap of air between them. Each layer carries a weak electric current. When something presses down, the top layer bends and touches the bottom layer, so the screen detects that exact spot. Because this design only needs physical pressure to connect the two layers, almost any object can operate it — a bare finger, a plastic stylus, or a gloved hand. This makes resistive screens cheap and tough enough for gas pumps and older game consoles. However, they react a little slowly, and the extra layers make the picture look dimmer.
¶3 A capacitive touchscreen works the opposite way. [A] Instead of two layers, a single layer under the glass holds an even electrical charge across its surface. Human skin naturally conducts electricity. [B] When a bare finger touches the glass, it draws away a tiny bit of that charge. Sensors at the edges calculate exactly where the charge dropped, which tells the screen where the touch happened. [C] A plastic stylus or thick glove cannot conduct electricity, so it draws no charge, and the screen ignores it. Capacitive screens react instantly and can track two fingers at once, letting a picture be pinched and zoomed. [D] Most smartphones and tablets made today use this design.
¶4 The two designs trade one advantage for another. A resistive screen accepts almost any touch, but it reacts slowly and looks a little dull. A capacitive screen reacts instantly, but only a conductive touch — bare skin or a special glove — will work. That trade-off explains a small daily mystery: why the same glove unlocks one phone and fails on another.
- stylus: a pen-shaped tool used to tap or write on a touchscreen
- conduct: to allow electricity to pass through
- sensor: a device that detects something, such as touch, and sends that information to a machine
Questions
11 questions — every TOEFL Reading question type, in test order.
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Highlighted: "Because this design only needs physical pressure to connect the two layers, almost any object can operate it — a bare finger, a plastic stylus, or a gloved hand."
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This natural ability turns out to be the key to how the screen works.
Where would the sentence best fit?
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Resistive touchscreen Capacitive touchscreen