[Density of coins, experiment] In this experiment, we will find the density of several types of coins, pennies, nickels, and quarters to determine which type of coin has the greatest density. [A penny, nickel, and quarter] Remember, density is the ratio of mass to volume. [Density = ratio of mass to volume] [Start with a HYPOTHESIS] Start by making a hypothesis about which type of coin has the greatest density. Be sure to record all data and calculations in the data table. We will measure the mass of each type of coin. [Electronic balance scale appears with a penny on it. There is a nickel to the left of the balance and a quarter to the right of the balance] Since the coins have a very small mass, it is easier to measure the mass of several coins and then calculate the mass on one coin. So let’s measure the mass of 5 of each type of coin and find the average. [A stack of five pennies on the scale. Five nickels to the left of the scale, five quarters to the right of the scale] The mass of 5 pennies is 12.5g. [Electronic balance scale massing five pennies with a reading of 12.5] To calculate the mass of one penny, divide 12.5g by the number of pennies, 5. [mass 12.5 divided by 5] So the average mass of one penny is 2.5g. Let’s find the average mass of a nickel and a quarter The mass of 5 nickels is 25g. [Five nickels are stacked on the scale with a reading of 25.0] The mass of 5 quarters is 28.4g. [Five quarters are stacked on the scale with a reading of 28.4] Find the average mass of each type of coin. [Nickel mass 25 divided by 5] [Quarter mass 28.4 divided by 5] Now let’s find the volume of each. Let’s use water displacement method. [Graduated cylinder] Again, it will be easier to use a number of each type of coin and find the average. [A stack of 20 pennies, 20 nickels, and 20 quarters appear] We’ll use 20 of each type of coin. [coins times 20] To find the volume of 20 pennies, we will add water to the graduated cylinder, record the volume, add 20 pennies and record the increase in volume. [Water is adde