1. Science Starters #4 7 th Grade

2. Find the lengths of the following pink lines to the nearest mm:

4. What is the total mass? Where should the riders be?

5. What is the total mass? Where should the riders be? 172 g http://www.ohaus.com/products/education/weblab/TBBread.html

6. Can you balance the balance below by using the fewest number of weights? Some weights can be used more than once

7. Can you balance the balance below by using the fewest number of weights? Some weights can be used more than once

8. These four cubes are the same shape and size and therefore have the same volume. They each contain different substances and have different masses. Using logic, place the cubes in order from least to most dense.

9. Helium balloons float in air, oil floats on top of water, and our atmosphere is above the water on the Earth’s surface. (Assume liquid water for the blue box.) Density tells us how tightly packed the atoms are within a given volume. This slide is modified from http://www.pbs.org/wgbh/nova/balloon/science/density/filling.htmlhttp://www.pbs.org/wgbh/nova/balloon/science/density/filling.html

10. Will it float in water? Determine if the following shapes will float in water by calculating the density for each item. D = M / V Mass: 15 g Volume: 20 mL Mass: 1000 g Volume: 50 mL Mass: 225 g Volume: 100 mL Mass: 10 g Volume: 200 mL www.middleschoolscience.comwww.middleschoolscience.com 2008

11. Will it float in water? Determine if the following shapes will float in water by calculating the density for each item. D = M / V Mass: 15 g Volume: 20 mL Density: 0.75 g/mL Mass: 1000 g Volume: 50 mL Density: 20.0 g/mL Mass: 225 g Volume: 100 mL Density: 2.25 g/mL Mass: 10 g Volume: 200 mL Density: 0.05 g/mL www.middleschoolscience.comwww.middleschoolscience.com 2008 If the density is less than 1.0 g/cm 3 then it will float. 1 g/mL = 1 g/cm 3