Three Science Experiments to Finish the School Year with a Bang!

Let's face it, as the school year comes to a close, teachers and students may face more difficulty with concentration and attention in the classroom. This time of year is traditionally reserved for projects, (and the odd movie). So, if you're looking for experiences to keep your students activated, look no further. Here are three exciting science experiments to undertake in your classroom.

Home-Made Lava Lamps:

Materials: (per team)

1. Vegetable Oil

2. Water

3. Food Coloring

4. Alka-Seltzer

5. x1 Bottle

6. Et Al.
   

Instructions:

1. Fill most of the bottle with vegetable oil, (80% of the bottle). Fill the rest of the bottle with water, (20%), and let it sink to the bottom.

2. Add a few drops of food coloring. This is water-based, so the food coloring will also sink to the bottom.

3. Break your Alka-Seltzer tablets into small pieces and add a little bit at a time to your lava lamp.

4. Enjoy your lava lamp by turning out the lights and shining a torch from underneath the bottle.
   

How It Works:

Water is a polar liquid with an uneven electrical charge which means it can attract other atoms. Oil is a non-polar liquid which is not attracted to water and therefore the two do not mix. The alka-seltzer reacts with water and produces carbon dioxide which attaches to the water droplets. As water is less dense than the oil, it will rise to the top of the bottle. At the top of the bottle, the gas bubbles burst, allowing the denser water to sink back to the bottom again.

Invisible Extinguishers:

Materials: (per team)

1. Tea Lights / Candles

2. Vinegar (200ml)

3. Baking Soda

4. x1 Glass (S)

5. x1 Glass (L)

6. Long Matches
   

Instructions:

1. Place the tea light / candle into the larger glass and use the long matches to light the wick.

2. Place your vinegar in a small glass and add a teaspoon of baking soda. (Be ready for the chemical reaction that produces an ‘eruption’).

3. Wait for the foam of your vinegar/baking soda mixture to disappear.

4. Enjoy watching the tea light / candle go out as you pour the air from your small glass over it.
   

How It Works:

Mixing vinegar, (an acid), with baking soda, (a base), creates a chemical reaction that produces carbon dioxide (CO2). Carbon dioxide is denser than normal air and therefore will not leave the smaller cup, where the reaction initially occurs. By pouring carbon dioxide over the lit tea light / candle, your carbon dioxide will push-up the air that the flame uses to burn, (which contains the abundance of the oxygen that fire needs). Therefore, the flame is extinguished!

Elephant Toothpaste

Materials: (per team)

1. Hydrogen Peroxide (3%)

2. Water

3. Food Coloring

4. x1 Sachet Of Yeast

5. x1 Bottle (1L)

6. Washing Up Liquid
   

Instructions:

1. Pour 100ml of hydrogen peroxide into the bottle and add a few drops of food coloring.

2. Add and stir 20ml of washing up liquid into the mixture.

3. In a separate container, mix warm water and yeast together. Leave the yeast to activate for 30-60 seconds.

4. Enjoy watching the reaction as you combine the warm yeast water with the mixture of hydrogen peroxide, food coloring and washing up liquid.
   

How It Works:

The yeast works as a catalyst. (A catalyst speeds up a reaction). The yeast breaks down and separates the oxygen molecules from the hydrogen peroxide, because this catalyst occurs so quickly we see the formation of a lot of oxygen bubbles in a very short amount of time. The experiment also creates an exothermic reaction which means the foam that is created is hot. (Do not directly touch the foam because of the use of hydrogen peroxide in the experiment).

What experiments do you like doing in the classroom? You can find our exciting experiments as part of Inspiring STEM Supplies Exciting Experiments series.