Winter Experiments in KDH

Since the first snow of the season, which was actually before winter officially began, KDH has been talking about snow and ice. That Friday, we brought in some snow and experimented putting salt on it and watercolor paint.

 What do we use to melt ice on the road? Salt. Salt's freezing/melting point is lower than 32'F which is the temperature at which water freezes. We continued with different experiments melting blocks of  ice with salt, adding food coloring and watching.

We also lifted up an ice cube with string and salt.

Last week we set out two glasses filled with room temperature tap water. We added salt to one glass turning it into salt water. We brought out purple ice cubes that we had made earlier. The question we had was: If we put a purple ice cube into each glass, which glass of water would melt the ice cube faster - the plain tap water or the salt water? Everyone thought about it and created his/her own hypothesis.

What happened?

The ice cube in the tap water began to melt and the purple food coloring spread down making the water in that glass, purple. The ice cube in the salt water melted very slowly. The purple water that came from the melted ice cube in the salt water, stayed on top of the clear salt water. Why? Evan told us that happened because the salt water is heavier! As the first ice cube was almost all melted, Sammy suggested that we add another ice cube to each glass. We did that and then went outside. A half hour later, when we came in, we observed that the ice cube in the salt water had again not melted much and the purple layer on top had stayed on top and gotten a little bigger!

Why to do you think this happened? Evan's dad suggested that the salt actually helped make that ice and water colder. Think about how we make ice cream. We use salt and ice.

We left the glasses out until the next morning and the purple layer was still on top of the salt water. This reminded us of the density column that we had experimented with on Chanukah.

What do you think about all this??

We saved the glass of salt water and waited and watched. The first week it looked the same. Then we noticed that slowly over time the purple layer on top was going further down in the glass. We examined it and found that crystals were also forming inside the glass. Because this made us think of a snow globe, and we like using our flashlights, we set the glass down and put a small snowman behind it. Look at what happens when you look through a glass of water at an object. The light bends and we could see two snowmen even though there was only one.

We are continuing to watch what will happen to the purple coloring and salt water in the glass.
Winter, cold, ice, salt, light, crystals, solutions.... all add up to science fun in KDH.

The next day:

The purple is getting bigger.....

Morah Ruth

Morah Sara