Grayden lined up four small blocks and stacked them, placing each block on top of the other. I heard him say, "These are towers." Then, Grayden moved to the block area and took some wooden blocks from the shelves. He arranged blocks of different sizes in a line, leaving gaps in between. I asked him what he was building. "These are wooden block dominoes," he replied.

After setting them up, he pushed the first block to make the others fall, but the rest remained upright. He tried again, but still, the other blocks didn't fall. I asked him why he thought the blocks behind the first one didn't fall. "I think the blocks were too heavy, so they didn't fall," he replied.

I explained, "The push you gave the first block is called a force." Then I asked, "Do you think we need a bigger force to move the heavy blocks?" It seemed Grayden thought about it and agreed with me. He then tried pushing the first block with more force. The other blocks moved a little bit. "It works! I need to push harder!" he exclaimed.

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