## The Poly Density Bottle

by: Tami O’Connor

So, do you ever bring discrepant events into your classroom to capture your students’ attention? If so, the Poly Density Bottle should be on your list of must-haves! As you can see, this is a one-liter bottle filled with clear liquid. Floating at mid-bottle are two bands of beads, with blue on top of the white.

On its own, this is intriguing to many students. The head scratching begins, however, once the bottle is given a good shake. As soon as everything starts to settle, students will observe that the white beads now float at the top of the liquid while the blue beads sink to the bottom. The liquid, once clear, now appears to be slightly cloudy.

But wait, there’s more… After about 30 seconds something interesting begins to happen. The white beads gradually sink down, the blue beads gradually begin to float up, and the liquid above and below the beads is again clear. Now the stumper… Why is this happening? Read the rest of this entry »

## Energy Sources in a Classroom

#### Energy Sources in a Classroom – Scavenger Hunt

by: Roy Bentley

I had the opportunity to attend the NSTA Convention that was held last month in Boston. It was a great show with amazing displays, topics and speakers. And of course, we had the PowerWheel there demonstrating how easy it is to teach about energy.

One of the points that came up during the show that struck me as worth exploring further was when we asked the teachers we were working with was “what sources of energy do we have in the classroom” The teachers at the show answered the lights, the power outlets, the sunshine through the windows and possibly the forced air from the heating/cooling system. No one referred to the faucet. When the teachers were asked if they had ever had the electricity fail in the school they all answered yes. When asked if they had ever experienced a water failure in the school they all answered no. It was concluded that the most reliable source of energy in the room was the faucet/(gravity).

Here is a simple classroom or home activity to help students realize how many energy sources are around them all the time! Read the rest of this entry »