 Welcome back to Kids Fun Science. My name is Ken. Today's experiment is the reusable cold packs. As always adult supervision is required. What you need for this experiment is a freezer bag and rubbing alcohol. Some safety precautions is rubbing alcohol is poisonous if ingested. Be sure to clearly label your bag do not drink or poisonous before putting in the freezer. Okay to set up this experiment you need your rubbing alcohol and some water, two cups of water and then you're going to I already pre-marked my cup one cup here for the rubbing alcohol that way I don't have to pour it into our measuring cup that we use for the house. So pre-dead that one cup which is 250 milliliters and two cups is 500 milliliters of water. Take your zip lock bag freezer bag I'm using a one gallon you can use a quart size would be actually be perfect. Pour the two cups of water into the the bag itself and then pour the one cup of rubbing alcohol and then takes up most the air out of it and then you want to seal it up you don't want to have a lot of air in there. So seal it up if there's too much air I'm gonna probably reopen it up and squeeze out the air there and then you're gonna want to mark the bag at this point because to do not drink or poison and then put it in your freezer overnight so you want to make sure this is in overnight and we will check back the next morning. So here it is the next morning I'm gonna go in and we can see it's not frozen over it's just like slush slushy we're normally you know it'd be completely frozen over this is just like a slushy it's very very cold I mean I could barely hold it too long just like a regular ice pack you would have and this is reusable so you can put it back in so it's very cold as you can see slushy and great for injuries if you want to use this so if you go ahead make your own you can reuse it and now I will tell you the science behind it. So the solution the bag will not freeze because rubbing alcohol has a much lower freezing point than water. Rubbing alcohol freezes at negative 89 Celsius where water freezes at zero Celsius so as a result the rubbing alcohol depresses the freezing point of the water. The temperature in a typical freezer are not cold enough to freeze this solution that we made. The cold pack here that was made in this experiment can be reused whenever the cold is required for an injury such as a reducing swelling and then it can be placed back in the freezer and reused over and over again so very useful here I hope you enjoyed this video remember to click thumbs up and to subscribe thanks for watching