Science Smarts: Absorption demonstration
By Patty Rooks on August 31, 2024.
Where did the summer go? Although the cooler starts to the day point that fall is just around the corner, I can hardly believe it is time to get back into the classroom. Sometimes it is hard to excite our students on the first few days, so I thought I would share one of my favourite demos which I hope will make them your favourite teacher this year. *Remember to ask an adult before doing this experiment. Materials – Water gel powder (OR a couple of diapers) – Bottle of water – Two paper cups (the kind you cannot see into) Procedure 1. Before the class gets there, prepare your cups. If you do not have water gel powder, cut several diapers open and shake out the powder in there. You want about 15 mL (one tablespoon). 2. Place the cups side by side on the counter. DO NOT identify either one to your class Once the class arrives and is ready for the demo continue. 3. Fill one cup with 250 mL of water and the other with one blue scoop of gel powder. 4. Walk up to a student, stand in front of them, and pour the water from the cup full of water into the cup with the scoop of gel powder. DO NOT let them see in the second cup. 5. Ask if it is OK to pour this over their head, are they afraid to get wet?! Try to make them believe they have a 50/50 chance of getting REALLY wet. Be convincing! 6. Tip the cup over as if you were going to pour water on their head! Watch them run away or scream. 7. Surprise, nothing will come out! 8. Say, “Just kidding,” but I would RUN FAST! 9. Engage the class into making a hypothesis as to why the student did not get wet. Make use of this FUN learning opportunity. What is going on? The secret to this “magic Trick” is the powder put in the cup. It is a superabsorbent polymer called sodium polyacrylate. When this powder comes into contact with water, the molecules of the polymer draw the water in and then hold onto it. In the case of Water Gel or the powder found in diapers, it’s able to absorb 100 times its own weight in water! This is how diapers are so absorbent and do not leak. Mark your calendars, the Praxis AGM is fast approaching Sept. 11. We are always looking for volunteer board members, so please consider joining us. If interested, please reach out to Patty for further details. 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. You can find us at: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403.527.5365, email: praxis@praxismh.ca. 21-20
