Praxis: Wow your students early this year
By Patty Rooks on August 31, 2019.
praxis@praxismh.ca@PraxisMedHat I know that I probably say this every year, but WOW, Where has the summer break gone? Welcome back to all educators. I know that you have all been preparing for weeks already. It may be hard to get those students excited those first few days back, but this activity is sure to excite them. Let’s get started! *Remember to ask an adult before doing this experiment. Materials – food colouring – package of yeast – warm water – measuring spoons – measuring cups – separate empty cup – stir stick or spoon to stir with – large clear empty soda bottle – peroxide (I like to get mine at the beauty store – it is a bit stronger than the 3% you can purchase at the drugstore) – dish soap – safety goggles – baking tray – flat empty counter or table to work on Procedure 1. Find a good place to work as this experiment could potentially make a mess. Outside would be perfect or a good sturdy counter will work too. 2. Put on your safety glasses – this is a must and a great opportunity to discuss lab safety with your students. Even the simplest of experiments can cause harm even with the best of intentions. 3. Place the empty soda bottle on the baking tray and set aside for now. 4. Measure three tablespoons (45 mL) of warm water into the empty cup. 5. Measure one tablespoon (15 mL) of dry yeast to the warm water. Stir it well and set aside for a minute or so. Watch what happens. 6. Measure 1/2 cup (125 mL) of hydrogen peroxide and carefully pour it into the empty soda bottle. 7. Add a few drops of food colouring of your choice. Swirl it around. 8. Squeeze three large squirts of dish soap into the peroxide mixture. 9. Have everyone stand back and slowly add the yeast mixture to the peroxide mixture. 10. Watch what happens. 11. Clean up your mess!! Explanation Many of you may know this experiment by the name “elephant toothpaste” because it looks like toothpaste being squeezed out of a tube and big enough for an elephant to use – it should foam up and squirt right out into the air! There is a bit of a complicated chemical reaction occurring in this pretty cool experiment! Let us look at this simply. Basically you start with peroxide and a bit of soap. You add a catalyst to this mixture – the yeast. As a result of this you start breaking down the peroxide into two of its components; oxygen and water. What you end up with is water and soap and a TON of tiny bubbles as a result of the oxygen being released. Educators do not forget to book your hands on Science Learning Kits early so you do not miss out on having them to use in y our classroom. Do not forget to call us for all of your science needs this school year; we are excited to be kicking off a great year once again in southeastern Alberta! Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. NOTE our NEW address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca. 35-34
