Identify a few strong-smelling items with which the children should be familiar. These could be a few different kinds of wood, a few particularly pungent flowers, fruit such as lemon or banana, and maybe a perfume. Add in a few items that don't have such a strong smell, like a bag of chips or a mild cheese. All these materials should be contained in a separate opaque box and prevented from contaminating each other. One by one, each child is blindfolded when it's his turn to smell the mysterious boxes. The children should write down what they think the object is from the smell, and rate how strong it smelled on a scale of 1 to 10, with 10 as the strongest smell. When everyone is finished smelling, ask what the children thought, then maybe hold a class discussion on what memories certain smells evoked.
Provide the students with a diagram of a human tongue. Present them with a small piece of lemon, a hard snack pretzel, a piece of dark chocolate and a fruit-flavored lollypop, or any other foods that can be categorized as sour, salty, bitter and sweet. Ask the students to try each item at the same time, as a class, and write in pencil on the diagram which bits of the tongue sense the taste of that particular food. After the students have tasted every item and written their guesses on the worksheet diagram, reveal the answers. Then ask the students to color in the different sections in the right color --- green for bitter, pink for sweet, blue for salty and yellow for sour.
Purchase 10 different grades of sandpaper. Cut a 2-inch square from each, making sure to write the grade on the back of the square. Ask the children to feel the sandpaper squares without turning the square over to see the grade. Then ask the children to rank the sandpaper pieces from roughest to smoothest. When the children are sure, turn over the squares to see if they got it right.
On an piece of paper, have the children draw a cross on the right side and a dot on the left, about 8 inches apart. Have the students stare at the cross with their heads about 20 inches away from the surface of the paper. Each child should close her right eye. The left eye should continue to focus on the cross, while the child gradually moves closer to the paper, only stopping when the dot on the left disappears. Explain that this is how we find the blind spot, the area of the retina that cannot respond to light.
Make a CD or a USB stick of various distinctive sounds. Have a range of different sounds, such as vehicles, birdsong or people laughing. Have a few mystery ones that the children may not have come across before, like dolphins or whales in the ocean. Make a handout that has a cartoon picture of an ear or somebody straining to listen in the center of the paper. Around this cartoon should be a number of empty bubbles --- as many bubbles as there are sounds on the CD. Make sure to number the bubbles to correspond to a sound on the CD. Make enough copies of the handout for each student, and have the children fill in the bubbles with what sound they think they are hearing. The children should give a little description of the sound.