Physics Unit

Activity I.1

Hot or Cold?

Stage 1.Using the sensations.

1. By yourself answer to the meaning that you have for the following expressions:

a) How cold is the ice¡ like minus than 0 degrees

b) How hot is he coffee¡ like more than 100 degrees

c) How cold is outside¡ like 20 to 27 degrees

d) How hot is inside the classroom¡ like 25 to 30 degrees

2. In a dynamic guided by your teacher, compare the answers of all your classmates.

a) What similarities or differences did you find compared with your answers?

Only in the ice, the majority of the students think the same.

b) What sense are related to the previous expressions?

The touch and the watch

3. Order the following objects of the classroom, form the coldest to the hottest: the textbook, the blackboard, your chair, the floor, the wall, the window glass, yourself.

1-the floor, 2-the blackboard, 3-the window glass, 4-the wall, 5-the textbook, 6-your chair, 7-yourself.

a) What sense did you use to discriminate the previous objects and yourself?

The touch

b) Were all the objects and you to the same or different temperature?

All were at different temperatures

c) If you consider that all the objects have a time in the classroom, would the appreciation of your answers to the previous questions change?

Yes, because all the things would be at the same temperature.

4. In dynamic, guided by your teacher, compare your answers with the ones of your classmates.

Stage 2.Proving the sensations.

5. For this activity you will use 3 beakers, warm and cold water, alcohol burner, (or Bunsen burner if the practice is I the lab).

6. Place in each beaker hot water, cold water and warm water, which you will obtain from mixing half of hot water and half of cold water.

7. Introduce the index finger of the right hand in the hot water and the index finger of the left hand in the cold water, next, introduce both fingers in the warm water.

8. When introducing both fingers in the warm water, did you notice some difference in both fingers? Yes, they don´t fell anything, they change the temperature to the warm water

9. Dou you believe that the touch is really reliable at the moment to decide if something is hot or cold? No

10. Discuss the answers of both questions in a plenary guided by your teacher.

Activity 5.2

Stage 2.Integrative activity.

1. Answer the following questions.

a) To what temperature would you obtain the same reading in the scales Celsius and Fahrenheit? R= To 40°C and 40°F

b) Why do liquids have expansion coefficient greater than the solids? R= in liquid the forces that keep them joined are not very high as in the solid state

c) Indicate the difference between heat and temperature. R= the temperature

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