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Mr. Giovannini,7th Grade |
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Science: Grade Seven Notes (A)Science: February 20-24
Heat Lab #7 Inquiry D13 "Melting Away" Question: How long would it take for a entire ice cube to melt in your hand? Procedure: 1-9 (page 298) Observation: Table: Melting of Ice Cube (p. 298) (Complete table, Questions 10,11,12, and graph (10.25) Mr. Giovannini's Results (Do Not Copy) This is an example Time (min) Mass of Ice Cube (g) 0 m 22 g 2 m 18 g 4 m 15 g 6 m 11 g 8 m 6 g Complete Question #10 Total Loss of mass (Initial Mass - Final Mass) ( 22 g - 6 g = 16 g) #11 Rate of melting (g/m) = overall change in mass of ice cube (g) / 8 min Rate = 16 g / 8 min Rate = 2 g/ min #12 Expected melting time for the total Ice Cube = starting mass of Ice Cube (g) / rate of melting (g/m) Melting Time = 22 g / 2 g per min Melting Time = 11 minutes Graph (10.25) p. 299 Conclusions: #15,16,17,18 -------------------------------------------------------------------------------------------------------------------------- QUICK LAB D14 (page 299) To Observe the effect of cooling gas??? Procedure: (State steps 1-4) Observations: Record what you saw happen? Conclusions: Why did the can Collapse? Complete Questions: #5,6,7 and attach to your handout Lab#7 The Science Behind The Collapsing Can: Why did the can collapse? We heated the can on the burner and made the water inside boil. As we did this the water vapor from the boil forced air out of the can. Once the can was filled with hot water vapor, it was cooled quickly by turning it upside down and submerging it in the cold water. The cooling process caused the water vapor inside the can to condense. Which in turn created a partial vacuum. The partial vacuum generated low pressure inside the can (lower than the 14.7 pounds per square inch that surrounds us). Then the higher air pressure of 14.7 pounds per square inch outside the can crushed it. The can was crushed / collapses when the air pressure outside became greater than the pressure inside. That pressure difference was greater than the can was able to withstand. The same thing happens when you collapse an aluminum can with your hand. Squeezing the sides of the can makes the pressure outside greater than the pressure inside. If you squeeze really har the can is crushed. Normally, air pressure inside a open can equals the pressure outside. But in this demonstration, all of the air was foreced out of the can by water vapor. Once the water vapor cooled and condensed, the air pressure inside the can became much less than the air pressure outside. Next the greater pressure outside the can crushed it. ------------------------------------------------------------------------------------------------------------------------------ Heat Lab: #5 Investigation (page 292) Question: Does Tap Water or Salt Water Boil faster???? Hypothesis: Salt Water will boil faster than Tap Water Procedure: Create a data table (Similar to one on page 292) a) Pour tap water into a graduated cylinder. Pour 250 ml into a beaker (A). Record temperature in your table. b) Repeat: then add 10 g of salt to 250 ml of tap water in second beaker. c) Record temperature. d) Place both beakers on a hotplate. e) Measure temperature for both beakers every 60 seconds. Record in table. f) Use the data collected to create a Line graph. g) x-axis is independent variable; y-axis is the dependent variable. Observations: a) table Distilled Water Time Temperature 0 20 1 35 2 43 3 52 4 58 5 66 6 73 7 77 8 82 9 87 10 92 11 97 Salt water Time Temp 0 20 1 35 2 47 3 57 4 62 5 72 6 76 7 82 8 86 9 90 10 94 11 94 Line Graph Time / Temperature b) Line graph Conclusions: Is there a difference between the two graphs. Does each reach the boiling point at the same time? Was your hypothesis correct? Write a summary paragraph that answers the question for this experiment. Support your answer with the data collected. Heat Unit Notes Mr. Giovannini
All Work to be completed in your Note book
Match the temperature with the activity
Boiling Water _____ Freezing water _____ Body Temperature _____ Interior of the Sun _____ Oven temperature to cook Pizza _____ Hottest day ever recorded on Earth _____ Coldest Temperature recorded on Earth _____ Temperature of Ice Cream _____ Air temperature in a Refrigerator _____ Coldest Temperature Possible (Absolute Zer0) _____
-10 C , 100 C , 12 000 000 C, 160 C, 0 C ,
37 C , 58 C, - 89 C , - 273 C , 7 C ,
1. Unit to measure Temperature? _________
2. Instrument to measure temperature? ______
3. What is Temperature?
4. What is Heat?
5. What is the unit to measure Heat?
6. What is the difference between temperature and Heat?
7. What happens when a substance a) Expands b) Contracts
8. As stated in the “Particle Theory”, when a substance is heated, 9. State the ten (10) Forms of Energy? 10. Write a brief note on each Form, and an example for each? 11. Energy Transformations: Example: Using a Electric Stove Transforming from Electrical Energy to Thermal Energy Energy Used to Energy Produced a) Television: _______________ __________________ b) Radio _______________ __________________ c) Automobile _______________ __________________ d) Food Blender _______________ __________________ e) Desktop Computer ___________ __________________ f) Laptop Computer ____________ ___________________ |
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