Grade 11 chemistry demos

Our grade 11 students have ongoing chemistry projects where they can choose to demonstrate a chemistry concept or paint on our large periodic table wall.

 

The wall is still in progress and students must add their creativity and add 2 pictures that relate to their element where they are able to paint directly on the wall!

The demonstrations are on a variety of topics.  The following are some excerpts where students present the concept of their work, ask the class some questions and proceed to demonstrate their explosive chemical knowledge (often literally)

Briggs Rauscher Osclillating Colour Change

 

Alkali Metals

Elephant Toothpaste

 

Rainbow Density Tower

 Density: Mass divided by volume

• As you add sugar to the water, more and more sugar molecules will take over the space, making the water more dense. The cup containing the most tablespoons of sugar will be the most dense, the cup with no tablespoons will be the least dense.
• • 1. Set out four beakers of sugar with different amounts of sugar
  • 2. Pour half a cup of hot water in each of the cups and stir to dissolve the sugar
  • 3. Add a different colour of food colouring to each cup
  • 4. Pour the first cup into a graduated cylinder. Using a syringe, carefully add water from the second cup, then the third cup, and finally the fourth cup. (most dense at the bottom)

In this brief video, you will find a demo of rainbow densities.

 

Dancing Coin:

______________

Stoichiometry Balloons

Here is a demonstration of adding different amounts of baking soda to a constant volume of vinegar to demonstrate the relationship of the moles of carbon dioxide made.  At some point, the ratio is not evident, because the amount of vinegar limits the amount of gas made:

Methane Bubbles

Here is a demonstration exploding methane bubbles performed in our villanova science labs:

Not only is this a cool demo – it’s a chance to discuss the impact of methane in the environment.

Figure 1 – Methane bubbles in lake Banff, Alberta [photo credits: Katey Walter]

• As seen in figure 1 methane bubbles formed in a lake Banff National Park in Alberta, Canada
• The bubbles form due to organic matter being consumed by Microbes on the bottom of the lake  during the summer

 

__________

 

 

 

Hydrogen Explosion

Another loud combustion reaction is the explosion of hydrogen gas.  Hydrogen gas has lead to many of the world’s biggest explosion including the Hindenberg explosion.

Here is a video of a class demonstration where a grade 11 student lights a hydrogen balloon on fire:

 

 

____________________________

Pumpkin Explosion:

Around Thanksgiving it is proper chemistry tradition to self carve a pumpkin using acetylene.  Acetylene is made in a reaction of calcium carbide and water.

CaC2 (s) + H2O (l) –> C2H2 (g) + Ca(OH)2 (aq)