What’s in the air?

In this session we will start to investigate the question –

  1. What is in the air we breath?

What should I be able to do at the end of this investigation? I should be able to …

  1. Construct different types of data displays and predict patterns.
  2. Describe and interpret different data sets.
  3. Communicate ideas, explanations and processes in a variety of ways, including multi-modal texts.
  4. Compare fractions with related denominators
  5. Make connections between fractions, decimals and percentages
  6. Calculate the mean, median and mode of a data set.
  7. Describe what ‘air’ is made up of.

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To answer this question we are going to do two experiments. The first experiment we are going to set up today so that we can look at the results in a few days time.

Activity 1. Air particles and air quality.air_quality

You will need.

  • Vaseline
  • string
  • black permanent marker
  • milk carton
  • hole punch
  • magnifying lens
  • digital camera

What to do.

1. Cut the carton into four flat pieces by cutting along the side seams of the carton. Cut each side into 3 square pieces, each piece will be approximately 7cm long and 7cm wide. You will have a total of 12 squares when you are done.

2. Using the hole punch, punch a hole in one corner of each square.

3. Tie a piece of string through the hole to make a loop for hanging the square up, on a tree branch for example.

4. Make a data sheet in Excel to record where you place your squares, and what data you later will collect from them:

Air Particles and Air Quality
5. Write the name of each location in your data table. Decide on your four locations. They can be anywhere within school ground. The best locations will be places where other students are not going to interfere with them.

6. Using your black permanent marker, draw a 2.5cm by 2.5cm box in the centre of the white side (what used to be the inside of the carton) of each square. On the other write “Science Experiment – please do not disturb”.

7. Write the name of the location on the bottom of each square, you will use three squares for each location.

8. At each location, find a place to hang up three of your collection squares. You can hang the squares from a tree branch, sign post, light post, or any other safe landmark. When tying them up make sure that the three squares do not touch each other.

9. Before you hang each square up, spread a thin layer of vaseline in the black box in the centre of each square with your finger. Hang up the collection square.

10. Leave your collection squares for 3–5 days.

11. After you have waited, it is time to collect your data from the squares.

12. Revisit each location bringing your data table, magnifying glass and a digital camera.

13. Remove the squares one at a time. Each time, use your magnifying glass to count the number of visible particles you see stuck in the Vaseline inside the boxed area. Write the number in your data table.

14. Take a picture of the square.

15. Proceed to the next square and/or location until you have collected all of your data and filled out your data table.

16. For each location you will have collected three sets of data, so you will want to average the data to get a better result. First add together the three counts and write the answer in the “TOTAL” box. Then divide this number by 3 and write the answer in the “Average” box.

17. Now you are ready to make a graph of your data. Make a bar graph by writing a scale for the number of particles on the left side (y-axis) and then by drawing a bar up to the correct number of particles for each location. Remember to label each bar of your graph, or make a colour key.

18. Which sites had the most particulate matter in the air? Is this what you expected? Were each of your three counts the same or different? What do you think this tells you about the relative air quality at each location?

19. In your blog start a new entry entitled “Air particles and quality”. Firstly, write a sentence stating what the purpose of the experiment was. Next, include your data table followed by one picture from each location. Finally answer the questions above. Remember to answer them in complete sentences.

Experiment adapted from http://www.sciencebuddies.org/science-fair-projects/project_ideas/EnvSci_p009.shtml#procedure 

Activity 2. The contents of air.

In the above activity you looked at some of the larger objects that are in the air we breath. What about the actual gases that make up air? What do you think is included? Do the contents of the air change the higher up in the atmosphere we go? In this activity we will investigate the air at ground level.
You are going to investigate the oxygen content of air, by making a comparison between fresh air (i.e. the air they inhale) and exhaled air. The length of time a candle burns can indicate changes in oxygen content between fresh air and exhaled air.
In your Blog, start a new post and call it “The contents of air”.
1.  In your tables groups discuss what you think will happen to the candle when it is lit and placed under the beaker. In your post write your prediction and reasons for why you think that way.
2. As a groups carry out the experiment and time how long the candle burns. Complete this six times and calculate the mean (average) burning time. Record this in your blog by completing the sentence, The average burning time for the candle under the jar was _____ seconds.
3. How did your data compare with the data from other groups? Explain this by calculating the mode and median of the classes data.
4. Look at the image of the composition of fresh air. Predict whether there are differences in the oxygen content of fresh air and the air we exhale. What would be a research question that could address this?
 air2
5. Set up the equipment as shown below. You will use your data from the first part ofair this activity as base-line data.
6. What would be some things in this experiment that could change? These are called variables and it is extremely important to keep as many as possible the same, so that the test is a fair test.
7. Complete the experiment six times, recording the time the candle stays alight. Calculate the mean (average) for your data and include this as a statement in your blog post by completing the sentence, The average burning time for the candle under the jar, when a person exhaled into the upturned jar was _____ seconds.
8.How did your data compare with the data from other groups? Explain this by calculating the mode and median of the classes data. How can you account for the two different times (upturned glass jar and upturned glass jar being exhaled into it). What does this tell us about ‘fresh’ air versus ‘exhaled air’?
Experiment adapted from http://www.plantscafe.net/modules/b_book_engl_t1_m1.pdf

 

Okay, so we know a little about what’s in air but how does that change the further you travel from the surface?

 

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