1. Dry Ice Lab

2. So, what is dry ice? Carbon dioxide (the stuff we exhale and heats up our atmosphere) Normally a gas under our conditions Only it is solid CO 2 ! Turns directly from solid to gas: Sublimation

3. Why are we doing this? Talk about phase changing – Solid  Gas is unusual Understand molecule movement and speed Understand energy in different phases Because it’s pretty sweet – Spoon singing – Air hockey – Make fog?

4. A couple things to understand Heat ALWAYS transfers from high energy (hot) things to low energy (cold) things The reason we feel ‘cold’ or ‘hot’ is dependent on energy movement – Is energy moving from us to the object? OR – Is energy moving from the object to us?

5. Why is it Dangerous to touch? We feel COLD when heat transfers from our bodies to other things. We feel HOT when heat transfers from an object to our bodies. All of our energy QUICKLY transfers into the dry ice, and we get a cold burn.

6. A warning… Dry ice is COLD: -109 degrees F (-78.5 degrees C) DO NOT TOUCH IT FOR A LONG TIME DO NOT PUT IT IN YOUR MOUTH DO NOT PUT IT IN ENCLOSED CONTAINERS (except balloon or film case)

7. Dry Ice Bomb http://www.youtube.com/watch?v=Zu0lQyOp w_I http://www.youtube.com/watch?v=Zu0lQyOp w_I (This is why you have to be 18 to buy it) DO NOT TRY AT HOME Why is this happening?