Gases of the air - Burning candle invesitgation

Question 1

Describe the experiment of “burning candle investigation”

Answer 1

1. Wear a lab coat and safety goggles and tie up your hair
2. Take four different sized jam jars and measure their volume using water and a measuring cylinder.
3. Calculate the volume of oxygen in the jar [ 21% of the total volume ]
   21/ 100 x volume of the jar = volume of oxygen in the jar
4. Ensure the beakers are as dry as possible
5. Take a tea light and place it on a heat
   proof mat , light it. Put the jam jar 1 over the top and start the stopwatch.
6. Time how long it takes for the tea light to go out in seconds. Repeat this twice more and take an average of the time taken.
7. Repeat the above procedure with the other three jam jars.

Question 2

Why does the candle eventually go out?

Answer 2

The oxygen inside the jar runs out

Question 3

What is the relationship between the volume of oxygen in the jar and the time taken for the candle to burn out.

Answer 3

The large jar contains more oxygen meaning ; the bigger the jar the longer the time would be.

Question 4

Why do you repeat your experiment and take an average?

Answer 4

To make sure the that first one is not an anomaly or a random occurence.

Question 5

An independent variable is one that you change. What was the independent variable in this reaction?

Answer 5

The size of the jar and the amount of oxygen in the jar

Question 6

The dependent variable is one that you record and changes because of the change in the independent variable. What is your dependent variable?

Answer 6

How long it takes for the fire to run out

Question 7

The control variables are the ones that you control and stay the same during an investigation. What were your control variables?

Answer 7

The percentage of oxygen or the candle