September
Have you ever noticed how many different kinds of balls there are in the sports section of the store? You need a specific ball for each different game--tennis, basketball, baseball, soccer, ping-pong, marbles, football, and so many more. This is because the design of each ball is for their specific game. Can you imagine playing basketball with a ping-pong ball, or tennis with a marble? It wouldn't work very well...
This month's activities are all about the physics of balls. You can talk with your girls about different balls, what they do, and what causes them to behave as they do. Why do basketballs, volleyballs, and ping-pong balls all bounce, but look and feel so different.
Experiment 1: Which ball bounces highest?
Supplies: Yardstick or measuring tape, Masking tape, Hard floor, Variety of balls, Partner
Challenge teams of girls to figure out which type of ball bounces the highest. Drop each ball from the same height and measure how high each ball bounces. Use the masking tape to mark the height, and then measure with the yardstick. Before you start, have them record their predictions of which ball will bounce highest. Then, after they have "collected their data", they can make a line graph, plotting the average height of bounces for each type of ball. This will tell them if their prediction was true.
Experiment 2: Does the floor affect the bounce?
Supplies: Same as above, Different floor surfaces (wood, carpet, concrete, grass, etc)
Do the same process as above, recording the height of each bounce on different floor surfaces. Does a ball bounce higher when on wood versus concrete, or carpet versus grass?
Experiment 3: Which ball falls faster?
Supplies: Variety of balls, Hard floor, Stopwatch, Partner
Have one partner drop each ball while the other times the drop with the stopwatch. Time each ball several times and get the average time. Compare different types of balls to see which drops fastest.
May
Did you know that when you bite into a Wintergreen Lifesaver, it makes a spark?
With the beginning of summer drawing near, you can give it a proper welcome with a sparks show!! This short and simple activity requires only one supply item and no background knowledge.
The first thing you need is a bag (or two or three, depending on how many girls you have) of Wintergreen Lifesavers. The type of lifesavers is very important. They must be wintergreen flavor (mint, spearmint, or others will NOT work), and they must have sugar.
Next, you need a very dark room. The best place is probably a basement or some other place where there are no windows. You can even do it during a night hike!
Have the girls sit facing each other. The best is for them to sit either on the floor or at a small table. They should have the lifesavers close and at the ready. Then, after you turn off the light (they should wait a few seconds to let their eyes adjust to the dark), one girl puts the lifesaver in her mouth, and crunches, being sure to chew with her mouth open (yay!!! All table etiquette goes out the window!). The second girl watches, and will see a spark!! Then switch roles, so the second girl can see the spark as well.
Why does this happen? Ask the girls what they think. The cause is when the sugar crystals break (as the lifesaver is chewed), it causes a spark. The scientific name of this phenomenon is Triboluminescence.
For Junior and Teen girls, you may want to extend this activity by having them experiment with other types of life savers, and then compare results. Then, they can use the library or internet to look up more information. They could give a short presentation to the group of their findings, or maybe locate other materials which display triboluminescence.