Our last big science activity for the year was with the densities of liquids. They had seven liquids: syrup, honey, dish soap, water, vegetable oil, isopropyl alcohol, and baby oil. (The water was dyed blue and the rubbing alcohol dyed red so that the students could easily see the layers. The baby oil is on top and is clear.) The students predicted the order of the liquids, from most dense to least dense. We then poured in each liquid and observed the order. Afterwards, we placed in four cylinders made of different materials and observed where they stayed in relation to the liquids. Our discussion included using our math knowledge of decimals to give the approximate density of each solid cylinder based on the given density of each liquid. Here are some pictures from that day.
The students completed two activities with graduated cylinders.
First, the students learned how to read the volume on a graduated cylinder, and practiced on stations around the room. There was a variety of cylinders, with different cylinders having different scales and intervals. Second, the students used the skill they had just learned to find the volume of irregular objects using displacement of water. They read the water level, placed the object in the water, then read it again to find the difference. Below are some pictures from these activities. The students calibrated spring scales using 1-gram paperclips. They used the spring scales to measure the mass of various objects, and compared the results with the other groups. They were able to see that these particular spring scales produced unreliable measurements, which led to a discussion on the importance of standardized measurement instruments. Pictures of the activity are below.
As part of the Floating and Sinking unit, the students designed boats of different sizes out of aluminum foil and tested to see how many marbles they would hold. We were able to have discussions about which designs consistently held more than the others, and observations about why. Here are some pictures from those days.
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