Pose a question regarding the relationship of weight (mass) to inertia. Find two people that have at least 30 lbs. of weight difference between them. One may be a teenager and one a 5 or 6-year-old child. Locate a swing set at a playground where two swings have equal lengths of chains so that the swings hang the same distance from the top bar. Have the two people sit on the swings. Have two other people pull them back an equal distance and let them start to swing, both at the same time. The people on the swing should stay as still as possible. Ask the question: "Will the person who has the most weight swing the longest amount of time before coming to a stop?"
Inertia causes an object to have a tendency to continue moving once it is in motion. Friction can act as a force that reduces inertia. Place one end of a 2-foot long piece of wood up on several books to form a ramp. Gather a plastic container that yogurt or butter comes in. Fill it with water and put on the lid. Set it on the ramp and see if it slides down. If not, add more books to raise the height of the ramp until the container just starts to slowly slide. Ask the question: "Can you increase the inertia of the contain by reducing friction so that it will slide easier and faster?"
Remove the board and soak the top with water. Place it in a refrigerator's freezer until ice forms on the board. With a spray water bottle, spray a mist of cold water on the board and place it back in the freezer. Do this several times until there is thin coating of ice on the board. Lay the board back on the books, put the plastic container on the ramp, and observe if the container slides easier. The ice has reduced friction between the board and the container.
Ask the question: "Does the inertia (momentum) of an object increase as speed increases?" The term "momentum" refers to the force with which an object is moving, quantifying the amount of inertia it has.
Outside, pour a bag of flour in a pile on a level area, such as a sidewalk. With your hands, push the flour together to make a pile 2 inches high and in the shape of a rectangle about 3 or 4 inches wide by 6 or 7 inches long. Level the top so it is flat. Stand over the flour holding a golf ball about 2 feet above the flour, and release it. The force of gravity will give momentum to the ball and it will create a "crater" in the flour pile. Stand on a small ladder and drop the ball again into the flour, but from a starting point 4 or 5 feet above the flour. Aim for a spot in the flour next to where the first crater was formed. Compare the two craters and reach a conclusion as to whether or not speed increases momentum.
In the previous experiment, the mass (weight) of the the golf ball stayed the same each time, but the speed of the ball at impact was changed. Ask the question: "If the speed stays the same but the mass changes, will momentum be affected?"
Set up a flour pile as in the previous project. This time, drop a pingpong ball from a height of 3 feet and a golf ball from the same height. Examine the displacement of flour and arrive at an answer to your question.