You know that friction also causes heat. Think about when you rub your hands together. It is friction that makes them warm. But why does this happen? Friction causes the molecules on rubbing surfaces to move faster. Faster moving particles have more heat energy. Heat from friction can be useful. Can you think of other places where you might find friction? Friction also lets you light a match. Heat from friction can also cause problems. It can cause a car to overheat. To reduce friction, oil is added to the engine. Oil coats the surfaces of moving parts. This coating of oil makes them slippery. When things are slippery there is less friction. Have you ever seen a sign that says, slippery when wet? This too has to do with friction. Water, like oil, can reduce friction. The wet surface may allow your shoes to slide more easily.

Question: "How does oil reduce friction between moving car parts?"

OPTIONS:
- no
- yes

Answer: "Slippery"

Response: yes

Late on the next Sunday afternoon Gifford had gone for a country walk which he had arranged to bring him round in time for the evening service at the little village church of Wynford standing just outside the park boundary. His way took him by well-remembered field-paths which, although towards the end of his walk darkness had set in, he had no difficulty in tracing. The last field he crossed brought him to a by-road joining the highway which ran through Wynford, the junction being about a quarter of a mile from the church. As he neared the stile which admitted to the road he saw, on the other side of the hedge and showing just above it, the head of a man. At the sound of his footsteps the man quickly turned, and, as for a moment the fitful moonlight caught his face, Gifford was sure he recognized Gervase Henshaw. But he took no notice and kept on his way to the stile, which he crossed and gained the road. As he did so he glanced back. A horse and trap was waiting there with Henshaw in it. He was now bending down, probably with the object of concealing his identity, and had moved on a few paces farther down the road.

Question: "Where did Gifford see Henshaw?"

OPTIONS:
- no
- yes

Answer: "By Road"

Response: no

Sound waves are mechanical waves. They can travel only through matter. They cannot travel through empty space. This was demonstrated in the 1600s by a scientist named Robert Boyle. Boyle placed a ticking clock in a sealed glass jar. The clock could be heard ticking through the air and glass of the jar. Then Boyle pumped the air out of the jar. The clock was still running, but the ticking could not be heard. Thats because the sound couldnt travel without air particles to transfer the sound energy. Is there any other place where sound cannot be heard? Here is a hint: is there any other place that does not have air molecules? Thats right, in space sound cannot be transferred. So can astronauts hear each other? Yes, they can, because they are in enclosed space stations or pressurized suits.In both cases, they are surrounded by air molecules. If they left their space ship and did not use their electronics, they would not be able to hear each other. Next time you watch a science fiction movie, think about this factoid. When spaceships are destroyed by hostile alien beings, there would be no sound heard. Sound waves can travel through many kinds of matter.

Question: "What can sound waves move through?"

OPTIONS:
- no
- yes

Answer: "Water"

Response: yes

The first rule is parental. The primitive monarchy is in the home. A young baby cries. The trained nurse turns on the light, lifts the baby, hushes it, sings to it, rocks it, and stills its weeping by caresses and song. When next the baby is put down to sleep, more cries, more soothing and disturbance, and the setting of a tiny instinct which shall some day be will--the power of control. The grandmother arrives on the scene. When baby cries, she plants the little one firmly in its crib, turns down the light, pats and soothes the tiny restless hands that fight the air, watches, waits. From the crib come whimpers, angry cries, yells, sobs, baby snarls and sniffles that die away in a sleepy infant growl. Silence, sleep, repose, and the building of life and nerve and muscle in the quiet and the darkness. The baby has been put in harmony with the laws of nature--the invigoration of fresh air, sleep, stillness--and the little one wakens and grows like a fresh, sweet rose. The mother, looking on, learns of the ways of God with men.

Question: "How many people come to comfort the baby?"

OPTIONS:
- no
- yes

Answer: "4 including the mother"

Response:
no