Acorn Squash and Watermelon

Yesterday, I decided to help my dad out and make dinner. We were having salmon and acorn squash. The salmon was cooked the previous night by my dad, so the only thing I had to do was cook the acorn squash. I didn't know where the squash was located, and asked my dad where it was. He told me it was on the counter where other food items were placed such as: acorn squash, butternut squash, a small watermelon grown in our garden, apples, and yams. I asked my dad if the acorn squash was green and he said yes. I picked up the small watermelon thinking it was an acorn squash. I cut open the "acorn squash." Inside the squash is red, and I finally realize it's not a squash. I figure out which one of the food items is an acorn squash and proceed to cook the acorn squash. When my dad finds out what I did he starts laughing at me. He can't believe that someone could mistake a watermelon for an acorn squash. I tell him it's easy when the watermelon is very small.