1. Energy Problem Solving, LEVEL d Q1Q2Q3Q4Q5

2. QUESTION 1a 4500 kJ 15000 kj 15 000 kJ lost in total How much is lost through the rest of the house? answer 4500 kJ lost through roof

3. QUESTION 1a answer Energy lost through the rest of the house = 15 000 – 4500 = 10 500 kJ Part b

4. QUESTION 1B ENERGY LOST FROM THE REST OF THE HOUSE. We have just calculated that 10 500 kJ of energy are lost in 24 hours. 24 hours = 1 day. How much energy is lost in 7 days? answer

5. QUESTION 1B answer ENERGY LOST FROM THE REST OF THE HOUSE. Energy lost in 7 days = 10 500 x 7 = 73 500 kJ

6. QUESTION 2a 80 o C50 o C 80 o C 40 o C 45 o C 10 minutes later CLICK DRAGON FOR NEXT SLIDE

7. The water in all three beakers has become cooler 80 o C50 o C 80 o C40 o C 80 o C45 o C 30 o C cooler 40 o C cooler 35 o C cooler Your conclusion must be based on the two variables in the experiment, and how they affect cooling. Can you spot the variables? Click here to see if you’re right!

8. The water in these two beakers has become cooler 80 o C50 o C 80 o C40 o C 30 o C cooler 40 o C cooler One variable is size of beaker. Think about how to complete the sentence, then click to see if you’re right … “The smaller the beaker, the bigger the drop in temperature. Click to see the other variable

9. The water in these two beakers has become cooler One variable is presence of lid. Think about how to complete the sentence, then click to see if you’re right … “A beaker without a lid cools down faster than a beaker with a lid. 80 o C40 o C 80 o C45 o C 40 o C cooler 35 o C cooler Part b

10. 80 o C QUESTION 2b 60 o C wool fur An experiment to find out if fur can prevent heat loss better than wool. Volumes of water are different. Starting temperatures are different. Sizes of beakers are different. Thicknesses of materials are different. This is one way to set up the experiment! There are FOUR things that make this experiment unfair. Can you spot them? Click when you’re ready. Click to see fair experiment

11. 80 o C QUESTION 2b wool Volumes of water are the same. Starting temperatures are the same. Sizes of beakers are the same. Thicknesses of materials are the same. … The only thing that is different is the insulating material (fur or wool). 80 o C fur A fair experiment to find out if fur can prevent heat loss better than wool.

12. QUESTION 3 A Note the time taken for the metal pin to fall off. B Light the Bunsen burner and start the stopclock. C Compare the times for the metal pins to fall off. D Repeat the experiment with the iron rod. Here are the “jumbled up” instructions. Think about how you could unjumble them. Click the mouse to see if you’re right. First step: Light the Bunsen burner and start the stopclock. Second step: Note the time taken for the metal pin to fall off. Third step: Repeat the experiment with the iron rod. Fourth step: Compare the times for the metal pins to fall off.

13. QUESTION 4 Time (hours)Temperature ( o C) 022 118 215 313 4? 4 o C drop 3 o C drop 2 o C drop There seems to be a pattern to the size of the temperature drop. ? By how much should the temperature drop here? (Click for answer) 1 o C drop You should, by now, have worked out the missing temperature. Click to see if you’re right! Time (hours)Temperature ( o C) 022 118 215 313 412

14. QUESTION 5a Temperature sensor 40 buzzer Outputs 80 Jennifer should look up pages 40 and 80. Part b

15. QUESTION 5b Truth tables 44 OR Gates 27 Gillian was trying to find out about OR gates and their truth tables.