Even simple physical science labs need to begin by discussing safety. Talk with students about things they can use to protect themselves as they do their lab work before beginning any experiments. Even if the safety items may be overkill, it’s still a wise idea to get into the practice of using them. For instance, if there are moving objects in use, it is a good idea to wear safety goggles to prevent any items getting in the eyes. Any time any chemicals are used, safety goggles as well as gloves should be worn to protect the body from splashes and any chemical reactions that could damage the person or the items they are wearing.
To prepare for labs, first gather together all the tools necessary. These can range from science notebooks to proper measuring tools. Before beginning any labs, be sure that students know how to use the tools that they will need for their labs. It’s a good idea to do a review by demonstrating how to properly use tools before the actual lab is begun.
To do a lab on friction, you must be able to demonstrate how friction exists whenever two solid objects come into contact together. One of the easiest ways to demonstrate this concept is to use different surfaces to show the impact that friction has on motion and how friction can be increased or decreased.
For this activity you will need 3 weights, string, a stop watch, a smooth surface and a rough surface. Attach 3 weights together with a string. Make sure there is about 10 inches of string between each weight. Set the weights on a smooth surface. Line the weights up so that they have the maximum amount of tension on the string. Set the stop watch and push the last weight off the side of the surface. Write down how long it took the second weight to be pulled from the surface. Now repeat the experiment with a rough surface. Discuss the impact friction had on the movement of the weights. How else could the friction be increased?
Motion and Energy
Many times students hear the term “lost energy”. In fact, there is no such thing as lost energy, only transformed energy. Demonstrate this to your students using one of these simple physical science labs.
For this lab you will need a ball and two students. Have the students face each other. Ask one student to place their hand face forward on a table. Ask the other student to roll the ball towards the facing hand. The student with the hand on the table should not try to catch the ball, but instead should allow it to bounce off of their hand. Ask the ball hits the students hand, it will bounce back in the opposite direction. Talk with students about how the motion of the ball changed when it came in contact with a form of resistance, but the energy was not lost, it simply changed direction.
Now have students stand facing one another. Ask the students to lightly toss the ball back and forth. Now ask the students to stop. Ask the student who is catching if they would like the thrower to throw the balls hard as they can. The student will likely say no as they don’t have a mitt. Discuss this with students. When a ball that is thrown hard is caught, what happens to the energy of the ball? Who absorbs the impact from this energy? Why is the impact harder when the ball is thrown harder?
For this experiment you will need a marble and a rock that is significantly larger than the marble. Take students outside and find a safe high point that the objects can be dropped from. Ask students which object they think will hit the ground first. Point out how much heavier the rock is than the marble. Ask a student to drop both objects at the same time from the high point. The objects will hit the ground at the same time as they are falling at the same rate of motion due to the laws of gravity. Discuss this concept with your students.