Acid Rain Demonstration

Burningof sulphur – acid rain demonstration (Science & Society connection)
Apparatus: gas bottle, BTB indicator, glass plate, deflagrating spoon & sulphur.
Directions:
1. Fill gas bottle with water and add a few drops of BTB (indicator turns yellow in an acid or remains blue in basic or neutral solutions).
Put ½ tsp (amount is not critical) into the spoon and heat over the Bunsen burner flame. Ask a student to turn off the light so that the violet flame can be viewed.
Lower the spoon into the gas bottle, taking care not to touch the sides (see photograph). Cover with the glass plate. The white gas (SO2 and SO3) will billow and fill the air space above the blue liquid. Douse the flame in a waiting container of water (Safety alert – toxic gas produced is, use a fume hood).
Discuss with the class about societal and environmental implications of factories burning sulphur and the products that will come out of the smokestacks, like sulphur dioxide and trioxide. During this time, these two gases will dissolve into the water to form sulphurous and sulphuric acid, changing the pH from neutral to acid.
Cover the top of the bottle completely with the glass plate and shake once. The blue coloured solution will dramatically change to yellow. This indicates that the solution is now an acid. Explain how this demonstration shows how we get acid rain and the effects of air pollution on our lakes.
Extension: In Southern Ontario, there is a buffering effect of limestone (CaO) that will react with water to form calcium hyroxide (CaO + H2O--> Ca(OH)2). Since metal hydroxides are bases, this counteracts the effect of the acid rain. Therefore, Southern Ontario is not as affected by acid rain as it could be.

Silver flakes make for a cool demo

This is an oldie but a goodie. This is a demonstration that I never get tired of.

Single Displacement Reactions
Demonstration: Reaction of copper with silver nitrate.
Apparatus: coil of copper wire, large test tube, silver nitrate solution (concentration is not crucial).
Directions:
1. Place copper wire into test tube of silver nitrate. Allow students to review the activity series and predict the products of the following reaction:
Cu + AgNO3 --> Ag + Cu(NO3)2
2. Observe the reaction (see photograph). Large, beautiful flakes of silver come out of solution and the clear, colourless silver nitrate is replaced by a blue solution of copper nitrate. This colour change is evidence that the copper has gone into the solution.

Sex and Evolution - The Mating Game

PBS has excellent resources to support an important topic that will move down to the grade 11 Biology level in the fall of 2009: Evolution.

Here is the address: http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html

There are a whole series of videos which can be purchased or you can show a variety of 10 min video clips from a range of topics including:

Why is Evolution Controversial Anyways? How does Evolution Really Work? and Did Humans Evolve?

I like the range of topics because it goes beyond outlining what Evolution is about to why it is important and controversial.


As well, there are some fun parts like the sex and evolution dating game. There is a host, a contestant and 3 bachelors behind the curtains. There are questions that you can ask the contestants such as: what would be the perfect gift? The bachelors are different species of animals so what they think of as the perfect mate will be very different.

Chem4kids Website - Wow!

Wow! I came across an excellent website for kids called http://www.chem4kids.com/. It should not be called chem4 kids since there is a biology, astronomy and earth science sections, too!

I don't what the target audience is, but it's a great overview of things for high school students. It has colour pictures to add interest. Done by Rader Studios, they have done justice to the topic, doing a great overview and making sure to have real life examples

Breadmaking - a Fun Way to Connect Real Life to Science

I love making bread. There's the activation step with the sugar, water and yeast where you can see the activation of the yeast (frothing). There's the kneading and the rising, the punching and the rising again. It's a bit like magic! I guess that's one of the things that I love about science. There are so many things that are like magic.

There are many connection points for breadmaking in the curriculum. The most obvious is grade 9 Science in the Reproduction unit (asexual reproduction in yeast). Another is during the grade 11 U Biology Cells unit, there is a part about aerobic and anaerobic respiration. One of the aspects that is mentioned is that some of the products are alcohol and carbon dioxide. During the making of bread, it is the carbon dioxide that makes it rise. You could equally make wine for the same reason and the side product would be alcohol. Other connections is the Grade 12 Biology, Metabolic Activities unit.

If you don't have much time, you can use the breakmaker and just show the class the activation of the yeast. Or, you could have the water, sugar, yeast in a water bottle with a balloon on the end and collect the carbon dioxide. It is even possible to do a gas test by pouring the carbon dioxide over a candle.

World Clock - Watching the World's Population in Realtime

I came across the following website today while reading our Science Teacher's magazine. The address is as follows: http://www.poodwaddle.com/clocks2.htm

When you get to the page, you can view the number of people being born, dying, having abortions, contracting AIDS/HIV, being diagnosed with heart disease or cancer. You can click different buttons to look at the data per year, month, week or NOW. That is the scariest button of all. This would definitely be useful for grade 12 U Biology - Population Dynamics unit.

The interesting thing about this website is that although it is just numbers presented to us, what is selected to be shown is very revealing. If you look at the number of abortions, why would they include that? In Canada, we have no abortion law, since abortion is considered a medical procedure and other medical procedures have no laws associated with them. But if you click on the abortion button, you get a picture of a cute baby appears with a large number, indicating the number of abortions obtained while viewing it. You can also get numbers associated with the amount of botched abortions but it is not included in the main stats included with the World Clock. This can connect with the grade 9 Science - reproduction unit, beginning of life issues.

Other connection points for this website is Grade 11 U Biology - Biodiversity unit (Bacteria and Viruses section). Deaths by HIV/AIDS are a staggering amount but what is surprising how close a second is death by diarrhea-related causes. I think that I can assume correctly that with clean drinking water and simple medicines, that that number would be zero.

The Joys of Sidewalk Chalk

I took my Chemistry 12 students out into the parking lot with a bucket of sidewalk chalk last semester. We had been talking about s, p, d and f orbitals and I love doing role play. I do a lot of role play in Biology. We chose a small element and went through the energy diagram for it, placing electrons (running students) in one at a time. It was interesting the questions that came up or occurred to me while we were doing this. You could see more clearly that some of the orbitals would overlap and were of a similar energy. One could also see that it is interesting to "look" at the atom at such a minute level and "zoom" in, so to speak.

I found that some students found it quite helpful and some found it confusing or really unhelpful. That was worth thinking about because it told me something about what kind of learners that they were.

A number of colleagues asked me about it because they saw me heading out into the parking lot with a bucket of chalk and my grade 12s. Also, I was able to ask for clarification from another fellow teacher as we moved through it.

It was definitely worthwhile to break out of the classroom and I will be searching for more small ways to do so.