HOW THINGS WORK. Tutorial one

Transcription

1 HOW THINGS WORK Tutorial one

2 OUTLINE The law of inertia Friction force Thermal expansion Centripetal

3 Experiments by Astronaut THE LAW OF INERTIA

4 HOW THINGS WORK? Newton's first law of motion states that "An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. Inertia: the resistance an object has to a change in its state of motion. Objects tend to "keep on doing what they're doing."

5 Try to list out the examples of Inertia THE LAW OF INERTIA

6 THE LAW OF INERTIA Things on a moving skateboard, like apple, minifigures.. Water in a moving bottle.. Pencil drop into a bottle straightly.. Boring apple watching..

7 FRICTION FORCE

8 HOW THINGS WORK? Frictional Force refers to the force generated by two surfaces that contacts and slide against each other. These forces are mainly affected by the surface texture and amount of force impelling them together. The angle and position of the object affect the amount of frictional force.

9 A book sliding across a desk will come to a stop because of the force of. A. gravitation B. friction C. acceleration D. normal Which direction does Friction act? A. Same B. Opposite There is friction when two objects are not in contact. A. True B. False

10 A book sliding across a desk will come to a stop because of the force of. A. gravitation B. friction C. acceleration D. normal Which direction does Friction act? A. Same B. Opposite There is friction when two objects are not in contact. A. True B. False

11 Try to list out the examples of friction FRICTION FORCE

12 HOW THINGS WORK? Sled Water support less friction than ice. Football Stop faster in rush surface than smooth one.

13 THERMAL EXPANSION

14 HOW THINGS WORK? Thermal Expansion: When an object expands and becomes larger due to a change in the object s temperature. Temperature: The average movement energy of the molecules in a substance.

15 THERMAL EXPANSION Which of the following is the best definition of thermal expansion? A. Molecules moving faster B. An object increasing in size due to increased temperature C. An object decreasing in size due to increased temperature D. An object never changing in size

16 Dancing Penny Experiment THERMAL EXPANSION

17 THERMAL EXPANSION Lay the coin flat over the opening of the bottle. Place a few drops of water or cooking oil at the edge of the coin, to form a seal between the coin and the lip of the bottle. Wrap both hands around the body of the bottle. The coin will begin to tap on the lip of the bottle

18 THERMAL EXPANSION Lay the coin flat over the opening of the bottle. Place a few drops of water or cooking oil at the edge of the coin, to form a seal between the coin and the lip of the bottle. Wrap both hands around the body of the bottle. The coin will begin to tap on the lip of the bottle

19 HOW THINGS WORK? In a closed container of any gas, there is a direct relationship between temperature and pressure; as temperature increases, so does pressure. The pressure increase is caused by the increase in motion of the gas molecules as they become warmer. The added energy (provided by the warm hands) increases the motion of the gas molecules until they lift the coin. As some of the gas escapes, the coin drops.

20 If the coin does not tap? How to improve it? HOW THINGS WORK?

21 HOW THINGS WORK? If the coin does not tap? How to improve it? Warmed air might be escaping between the coin and the lip of the bottle. Add a few more drops of water or oil. The temperature does not increase enough. Warming the bottle by hot water.

22 THERMAL EXPANSION

23 CENTRIPETAL FORCE

24 HOW THINGS WORK? Centripetal Force A centripetal force is a net force that acts on an object to keep it moving along a circular path. Centrifugal force is ubiquitous in our daily lives. We experience it when we round a corner in a car or when an airplane banks into a turn. We see it in the spin cycle of a washing machine or when children ride on a merry-goround. One day it may even provide artificial gravity for space ships and space stations.